Lidar ( / ˈ l aɪ d ɑːr / , also LIDAR , LiDAR or LADAR , an acronym of "light detection and ranging" or "laser imaging, detection, and ranging" ) is a method for determining ranges by targeting an object or a surface with a laser and measuring the time for the reflected light to return to the receiver. Lidar may operate in a fixed direction (e.g., vertical) or it may scan multiple directions, in which case it is known as lidar scanning or 3D laser scanning , a special combination of 3-D scanning and laser scanning . Lidar has terrestrial, airborne, and mobile applications.
146-531: The Airbus Vahana ( Sanskrit : Vāhana , or Vahanam literally means "vehicle") was an electric-powered eight-propeller VTOL personal air vehicle prototype , or eVTOL , financed by A³ (pronounced "A-cubed"), by Airbus and Airbus Urban Mobility. The Vahana project started in 2016 as one of the first projects at A³ , the advanced projects and partnerships outpost of Airbus Group in Silicon Valley . Airbus "envision[s] Vahana being used by everyday commuters as
292-417: A time-of-flight camera is used to collect information about both the 3-D location and intensity of the light incident on it in every frame. However, in scanning lidar, this camera contains only a point sensor, while in flash lidar, the camera contains either a 1-D or a 2-D sensor array , each pixel of which collects 3-D location and intensity information. In both cases, the depth information is collected using
438-399: A combination with a polygon mirror, and a dual axis scanner . Optic choices affect the angular resolution and range that can be detected. A hole mirror or a beam splitter are options to collect a return signal. Two main photodetector technologies are used in lidar: solid state photodetectors, such as silicon avalanche photodiodes , or photomultipliers . The sensitivity of the receiver
584-722: A cost-comparable replacement for short-range urban transportation like cars or trains". It was planned to be a part of urban air mobility . The project was finished in December 2019. The convertiplane aircraft design, funded by the European aircraft manufacturer Airbus, called Vahana (Sanskrit: "vehicle"), started in 2016. It was being developed at A³ (A-cubed), the expanded project and partnership outpost of Airbus in Silicon Valley. Airbus said "Our work on this demonstrator confirms our belief that fully autonomous vehicles will allow us to achieve
730-534: A dead language in the most common usage of the term. Pollock's notion of the "death of Sanskrit" remains in this unclear realm between academia and public opinion when he says that "most observers would agree that, in some crucial way, Sanskrit is dead." The Sanskrit language scholar Moriz Winternitz states, Sanskrit was never a dead language and it is still alive though its prevalence is lesser than ancient and medieval times. Sanskrit remains an integral part of Hindu journals, festivals, Ramlila plays, drama, rituals and
876-423: A different principle described in a Flash Lidar below. Microelectromechanical mirrors (MEMS) are not entirely solid-state. However, their tiny form factor provides many of the same cost benefits. A single laser is directed to a single mirror that can be reoriented to view any part of the target field. The mirror spins at a rapid rate. However, MEMS systems generally operate in a single plane (left to right). To add
1022-738: A distance requires a powerful burst of light. The power is limited to levels that do not damage human retinas. Wavelengths must not affect human eyes. However, low-cost silicon imagers do not read light in the eye-safe spectrum. Instead, gallium-arsenide imagers are required, which can boost costs to $ 200,000. Gallium-arsenide is the same compound used to produce high-cost, high-efficiency solar panels usually used in space applications. Lidar can be oriented to nadir , zenith , or laterally. For example, lidar altimeters look down, an atmospheric lidar looks up, and lidar-based collision avoidance systems are side-looking. Laser projections of lidars can be manipulated using various methods and mechanisms to produce
1168-416: A few peak returns, while more recent systems acquire and digitize the entire reflected signal. Scientists analysed the waveform signal for extracting peak returns using Gaussian decomposition . Zhuang et al, 2017 used this approach for estimating aboveground biomass. Handling the huge amounts of full-waveform data is difficult. Therefore, Gaussian decomposition of the waveforms is effective, since it reduces
1314-550: A green spectrum (532 nm) laser beam. Two beams are projected onto a fast rotating mirror, which creates an array of points. One of the beams penetrates the water and also detects the bottom surface of the water under favorable conditions. Water depth measurable by lidar depends on the clarity of the water and the absorption of the wavelength used. Water is most transparent to green and blue light, so these will penetrate deepest in clean water. Blue-green light of 532 nm produced by frequency doubled solid-state IR laser output
1460-581: A language competed with numerous, less exact vernacular Indian languages called Prakritic languages ( prākṛta - ). The term prakrta literally means "original, natural, normal, artless", states Franklin Southworth . The relationship between Prakrit and Sanskrit is found in Indian texts dated to the 1st millennium CE. Patañjali acknowledged that Prakrit is the first language, one instinctively adopted by every child with all its imperfections and later leads to
1606-522: A means for a community of speakers, separated by geography or time, to share and understand profound ideas from each other. These speculations became particularly important to the Mīmāṃsā and the Nyaya schools of Hindu philosophy, and later to Vedanta and Mahayana Buddhism, states Frits Staal —a scholar of Linguistics with a focus on Indian philosophies and Sanskrit. Though written in a number of different scripts,
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#17331225971211752-410: A microscopic array of individual antennas. Controlling the timing (phase) of each antenna steers a cohesive signal in a specific direction. Phased arrays have been used in radar since the 1940s. On the order of a million optical antennas are used to see a radiation pattern of a certain size in a certain direction. To achieve this the phase of each individual antenna (emitter) are precisely controlled. It
1898-413: A moving vehicle to collect data along a path. These scanners are almost always paired with other kinds of equipment, including GNSS receivers and IMUs . One example application is surveying streets, where power lines, exact bridge heights, bordering trees, etc. all need to be taken into account. Instead of collecting each of these measurements individually in the field with a tachymeter , a 3-D model from
2044-454: A natural part of the earliest Vedic language, and that these developed in the centuries after the composition had been completed, and as a gradual unconscious process during the oral transmission by generations of reciters. The primary source for this argument is internal evidence of the text which betrays an instability of the phenomenon of retroflexion, with the same phrases having sandhi-induced retroflexion in some parts but not other. This
2190-479: A negative evidence to Pollock's hypothesis, but it is not positive evidence. A closer look at Sanskrit in the Indian history after the 12th century suggests that Sanskrit survived despite the odds. According to Hanneder, On a more public level the statement that Sanskrit is a dead language is misleading, for Sanskrit is quite obviously not as dead as other dead languages and the fact that it is spoken, written and read will probably convince most people that it cannot be
2336-508: A new imaging chip with more than 16,384 pixels, each able to image a single photon, enabling them to capture a wide area in a single image. An earlier generation of the technology with one fourth as many pixels was dispatched by the U.S. military after the January 2010 Haiti earthquake. A single pass by a business jet at 3,000 m (10,000 ft) over Port-au-Prince was able to capture instantaneous snapshots of 600 m (2,000 ft) squares of
2482-596: A pan-Indo-Aryan accessibility to information and knowledge in the ancient and medieval times, in contrast to the Prakrit languages which were understood just regionally. It created a cultural bond across the subcontinent. As local languages and dialects evolved and diversified, Sanskrit served as the common language. It connected scholars from distant parts of South Asia such as Tamil Nadu and Kashmir, states Deshpande, as well as those from different fields of studies, though there must have been differences in its pronunciation given
2628-431: A point cloud can be created where all of the measurements needed can be made, depending on the quality of the data collected. This eliminates the problem of forgetting to take a measurement, so long as the model is available, reliable and has an appropriate level of accuracy. Terrestrial lidar mapping involves a process of occupancy grid map generation . The process involves an array of cells divided into grids which employ
2774-407: A process to store the height values when lidar data falls into the respective grid cell. A binary map is then created by applying a particular threshold to the cell values for further processing. The next step is to process the radial distance and z-coordinates from each scan to identify which 3-D points correspond to each of the specified grid cell leading to the process of data formation. There are
2920-573: A refined and standardized grammatical form that emerged in the mid-1st millennium BCE and was codified in the most comprehensive of ancient grammars, the Aṣṭādhyāyī ('Eight chapters') of Pāṇini . The greatest dramatist in Sanskrit, Kālidāsa , wrote in classical Sanskrit, and the foundations of modern arithmetic were first described in classical Sanskrit. The two major Sanskrit epics, the Mahābhārata and
3066-534: A restrained language from which archaisms and unnecessary formal alternatives were excluded". The Classical form of the language simplified the sandhi rules but retained various aspects of the Vedic language, while adding rigor and flexibilities, so that it had sufficient means to express thoughts as well as being "capable of responding to the future increasing demands of an infinitely diversified literature", according to Renou. Pāṇini included numerous "optional rules" beyond
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#17331225971213212-490: A scanning effect: the standard spindle-type, which spins to give a 360-degree view; solid-state lidar, which has a fixed field of view, but no moving parts, and can use either MEMS or optical phased arrays to steer the beams; and flash lidar, which spreads a flash of light over a large field of view before the signal bounces back to a detector. Lidar applications can be divided into airborne and terrestrial types. The two types require scanners with varying specifications based on
3358-400: A second dimension generally requires a second mirror that moves up and down. Alternatively, another laser can hit the same mirror from another angle. MEMS systems can be disrupted by shock/vibration and may require repeated calibration. Image development speed is affected by the speed at which they are scanned. Options to scan the azimuth and elevation include dual oscillating plane mirrors,
3504-439: A similar phonetic structure to Tamil. Hock et al. quoting George Hart state that there was influence of Old Tamil on Sanskrit. Hart compared Old Tamil and Classical Sanskrit to arrive at a conclusion that there was a common language from which these features both derived – "that both Tamil and Sanskrit derived their shared conventions, metres, and techniques from a common source, for it is clear that neither borrowed directly from
3650-500: A stand-alone word in 1963 suggests that it originated as a portmanteau of " light " and "radar": "Eventually the laser may provide an extremely sensitive detector of particular wavelengths from distant objects. Meanwhile, it is being used to study the Moon by 'lidar' (light radar) ..." The name " photonic radar " is sometimes used to mean visible-spectrum range finding like lidar. Lidar's first applications were in meteorology, for which
3796-404: A total flight time of over 13 hours and a distance of 903 km were made. The longest single flight duration until then was 19 minutes, 56 seconds and the longest single distance covered has been 50,24 km. Configurations include electric helicopter and eight fan tilt-wing . For both configurations the hover performance estimates were based on blade element momentum theory . Vahana found
3942-440: A wide range of materials, including non-metallic objects, rocks, rain, chemical compounds, aerosols , clouds and even single molecules . A narrow laser beam can map physical features with very high resolutions ; for example, an aircraft can map terrain at 30-centimetre (12 in) resolution or better. The essential concept of lidar was originated by E. H. Synge in 1930, who envisaged the use of powerful searchlights to probe
4088-539: A wide variety of lidar applications, in addition to the applications listed below, as it is often mentioned in National lidar dataset programs. These applications are largely determined by the range of effective object detection; resolution, which is how accurately the lidar identifies and classifies objects; and reflectance confusion, meaning how well the lidar can see something in the presence of bright objects, like reflective signs or bright sun. Companies are working to cut
4234-692: Is a classical language belonging to the Indo-Aryan branch of the Indo-European languages . It arose in South Asia after its predecessor languages had diffused there from the northwest in the late Bronze Age . Sanskrit is the sacred language of Hinduism , the language of classical Hindu philosophy , and of historical texts of Buddhism and Jainism . It was a link language in ancient and medieval South Asia, and upon transmission of Hindu and Buddhist culture to Southeast Asia, East Asia and Central Asia in
4380-627: Is a case study that used the voxelisation approach for detecting dead standing Eucalypt trees in Australia. Terrestrial applications of lidar (also terrestrial laser scanning ) happen on the Earth's surface and can be either stationary or mobile. Stationary terrestrial scanning is most common as a survey method, for example in conventional topography, monitoring, cultural heritage documentation and forensics. The 3-D point clouds acquired from these types of scanners can be matched with digital images taken of
4526-508: Is akin to that of Latin and Ancient Greek in Europe. Sanskrit has significantly influenced most modern languages of the Indian subcontinent , particularly the languages of the northern, western, central and eastern Indian subcontinent. Sanskrit declined starting about and after the 13th century. This coincides with the beginning of Islamic invasions of South Asia to create, and thereafter expand
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4672-447: Is another parameter that has to be balanced in a lidar design. Lidar sensors mounted on mobile platforms such as airplanes or satellites require instrumentation to determine the absolute position and orientation of the sensor. Such devices generally include a Global Positioning System receiver and an inertial measurement unit (IMU). Lidar uses active sensors that supply their own illumination source. The energy source hits objects and
4818-407: Is assumed to be 6.3 kW/kg. Both configuration will assume 15 kg for avionics components and 15 kg for a crash rated seat. electrical actuators will take 0.65 kg each (8 units for helicopter and 12 units for tilt-wing). Additionally, the tilt-wing has two actuators (4 kg each). An additional 10% is for fittings and miscellaneous hardware. The cruise power of the tilt-wing
4964-481: Is carried out with a Lidar system, together with cameras and radar . Data from Electric VTOL News General characteristics Performance Related development Aircraft of comparable role, configuration, and era Related lists Sanskrit language Sanskrit ( / ˈ s æ n s k r ɪ t / ; attributively 𑀲𑀁𑀲𑁆𑀓𑀾𑀢𑀁 , संस्कृत- , saṃskṛta- ; nominally संस्कृतम् , saṃskṛtam , IPA: [ˈsɐ̃skr̩tɐm] )
5110-438: Is commonly used to make high-resolution maps, with applications in surveying , geodesy , geomatics , archaeology , geography , geology , geomorphology , seismology , forestry , atmospheric physics , laser guidance , airborne laser swathe mapping (ALSM), and laser altimetry . It is used to make digital 3-D representations of areas on the Earth's surface and ocean bottom of the intertidal and near coastal zone by varying
5256-454: Is for the green laser light to penetrate water about one and a half to two times Secchi depth in Indonesian waters. Water temperature and salinity have an effect on the refractive index which has a small effect on the depth calculation. The data obtained shows the full extent of the land surface exposed above the sea floor. This technique is extremely useful as it will play an important role in
5402-452: Is found in the writing of Bharata Muni , the author of the ancient Natya Shastra text. The early Jain scholar Namisādhu acknowledged the difference, but disagreed that the Prakrit language was a corruption of Sanskrit. Namisādhu stated that the Prakrit language was the pūrvam ('came before, origin') and that it came naturally to children, while Sanskrit was a refinement of Prakrit through "purification by grammar". Sanskrit belongs to
5548-401: Is lower than the cruise power of an electric helicopter. The disk loading for both configurations is similar to those of many existing light helicopters . The electric helicopter hover power at short ranges is lower than those of the tilt-wing. Some drawings and explanations of Vahana can be seen under SELF-PILOTED AIRCRAFT FOR PASSENGER OR CARGO TRANSPORTATION . One of the reasons why Vahana
5694-418: Is not visible in night vision goggles , unlike the shorter 1,000 nm infrared laser. Airborne topographic mapping lidars generally use 1,064 nm diode-pumped YAG lasers, while bathymetric (underwater depth research) systems generally use 532 nm frequency-doubled diode pumped YAG lasers because 532 nm penetrates water with much less attenuation than 1,064 nm. Laser settings include
5840-448: Is processed using a toolbox called Toolbox for Lidar Data Filtering and Forest Studies (TIFFS) for lidar data filtering and terrain study software. The data is interpolated to digital terrain models using the software. The laser is directed at the region to be mapped and each point's height above the ground is calculated by subtracting the original z-coordinate from the corresponding digital terrain model elevation. Based on this height above
5986-524: Is rare in the later version of the language. The Homerian Greek, like Ṛg-vedic Sanskrit, deploys simile extensively, but they are structurally very different. The early Vedic form of the Sanskrit language was far less homogenous compared to the Classical Sanskrit as defined by grammarians by about the mid-1st millennium BCE. According to Richard Gombrich—an Indologist and a scholar of Sanskrit, Pāli and Buddhist Studies—the archaic Vedic Sanskrit found in
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6132-479: Is taken along with evidence of controversy, for example, in passages of the Aitareya-Āraṇyaka (700 BCE), which features a discussion on whether retroflexion is valid in particular cases. The Ṛg-veda is a collection of books, created by multiple authors. These authors represented different generations, and the mandalas 2 to 7 are the oldest while the mandalas 1 and 10 are relatively the youngest. Yet,
6278-708: Is the ability to filter out reflections from vegetation from the point cloud model to create a digital terrain model which represents ground surfaces such as rivers, paths, cultural heritage sites, etc., which are concealed by trees. Within the category of airborne lidar, there is sometimes a distinction made between high-altitude and low-altitude applications, but the main difference is a reduction in both accuracy and point density of data acquired at higher altitudes. Airborne lidar can also be used to create bathymetric models in shallow water. The main constituents of airborne lidar include digital elevation models (DEM) and digital surface models (DSM). The points and ground points are
6424-437: Is the relationship between words and their meanings in the context of a community of speakers, whether this relationship is objective or subjective, discovered or is created, how individuals learn and relate to the world around them through language, and about the limits of language? They speculated on the role of language, the ontological status of painting word-images through sound, and the need for rules so that it can serve as
6570-417: Is the standard for airborne bathymetry. This light can penetrate water but pulse strength attenuates exponentially with distance traveled through the water. Lidar can measure depths from about 0.9 to 40 m (3 to 131 ft), with vertical accuracy in the order of 15 cm (6 in). The surface reflection makes water shallower than about 0.9 m (3 ft) difficult to resolve, and absorption limits
6716-476: Is very difficult, if possible at all, to use the same technique in a lidar. The main problems are that all individual emitters must be coherent (technically coming from the same "master" oscillator or laser source), have dimensions about the wavelength of the emitted light (1 micron range) to act as a point source with their phases being controlled with high accuracy. Several companies are working on developing commercial solid-state lidar units but these units utilize
6862-526: The Bhagavata Purana , the Panchatantra and many other texts are all in the Sanskrit language. The Classical Sanskrit with its exacting grammar was thus the language of the Indian scholars and the educated classes, while others communicated with approximate or ungrammatical variants of it as well as other natural Indian languages. Sanskrit, as the learned language of Ancient India, thus existed alongside
7008-568: The Dalai Lama , the Sanskrit language is a parent language that is at the foundation of many modern languages of India and the one that promoted Indian thought to other distant countries. In Tibetan Buddhism, states the Dalai Lama, Sanskrit language has been a revered one and called legjar lhai-ka or "elegant language of the gods". It has been the means of transmitting the "profound wisdom of Buddhist philosophy" to Tibet. The Sanskrit language created
7154-511: The Hughes Aircraft Company introduced the first lidar-like system in 1961, shortly after the invention of the laser. Intended for satellite tracking, this system combined laser-focused imaging with the ability to calculate distances by measuring the time for a signal to return using appropriate sensors and data acquisition electronics. It was originally called "Colidar" an acronym for "coherent light detecting and ranging", derived from
7300-613: The Indo-European family of languages . It is one of the three earliest ancient documented languages that arose from a common root language now referred to as Proto-Indo-European : Other Indo-European languages distantly related to Sanskrit include archaic and Classical Latin ( c. 600 BCE–100 CE, Italic languages ), Gothic (archaic Germanic language , c. 350 CE ), Old Norse ( c. 200 CE and after), Old Avestan ( c. late 2nd millennium BCE ) and Younger Avestan ( c. 900 BCE). The closest ancient relatives of Vedic Sanskrit in
7446-628: The National Center for Atmospheric Research used it to measure clouds and pollution. The general public became aware of the accuracy and usefulness of lidar systems in 1971 during the Apollo ;15 mission, when astronauts used a laser altimeter to map the surface of the Moon. Although the English language no longer treats "radar" as an acronym, (i.e., uncapitalized), the word "lidar" was capitalized as "LIDAR" or "LiDAR" in some publications beginning in
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#17331225971217592-744: The Rigveda had already evolved in the Vedic period, as evidenced in the later Vedic literature. Gombrich posits that the language in the early Upanishads of Hinduism and the late Vedic literature approaches Classical Sanskrit, while the archaic Vedic Sanskrit had by the Buddha 's time become unintelligible to all except ancient Indian sages. The formalization of the Saṃskṛta language is credited to Pāṇini , along with Patañjali's Mahābhāṣya and Katyayana's commentary that preceded Patañjali's work. Panini composed Aṣṭādhyāyī ('Eight-Chapter Grammar'), which became
7738-532: The Rigveda , a collection of 1,028 hymns composed between 1500 BCE and 1200 BCE by Indo-Aryan tribes migrating east from the mountains of what is today northern Afghanistan across northern Pakistan and into northwestern India. Vedic Sanskrit interacted with the preexisting ancient languages of the subcontinent, absorbing names of newly encountered plants and animals; in addition, the ancient Dravidian languages influenced Sanskrit's phonology and syntax. Sanskrit can also more narrowly refer to Classical Sanskrit ,
7884-526: The Rāmāyaṇa , however, were composed in a range of oral storytelling registers called Epic Sanskrit which was used in northern India between 400 BCE and 300 CE, and roughly contemporary with classical Sanskrit. In the following centuries, Sanskrit became tradition-bound, stopped being learned as a first language, and ultimately stopped developing as a living language. The hymns of the Rigveda are notably similar to
8030-406: The sandhi rules, both internal and external. Quite many words found in the early Vedic Sanskrit language are never found in late Vedic Sanskrit or Classical Sanskrit literature, while some words have different and new meanings in Classical Sanskrit when contextually compared to the early Vedic Sanskrit literature. Arthur Macdonell was among the early colonial era scholars who summarized some of
8176-416: The time of flight of the laser pulse (i.e., the time it takes each laser pulse to hit the target and return to the sensor), which requires the pulsing of the laser and acquisition by the camera to be synchronized. The result is a camera that takes pictures of distance, instead of colors. Flash lidar is especially advantageous, when compared to scanning lidar, when the camera, scene, or both are moving, since
8322-500: The verbal adjective sáṃskṛta- is a compound word consisting of sáṃ ('together, good, well, perfected') and kṛta - ('made, formed, work'). It connotes a work that has been "well prepared, pure and perfect, polished, sacred". According to Biderman, the perfection contextually being referred to in the etymological origins of the word is its tonal—rather than semantic—qualities. Sound and oral transmission were highly valued qualities in ancient India, and its sages refined
8468-414: The 13th century, a premier center of Sanskrit literary creativity, Sanskrit literature there disappeared, perhaps in the "fires that periodically engulfed the capital of Kashmir" or the "Mongol invasion of 1320" states Pollock. The Sanskrit literature which was once widely disseminated out of the northwest regions of the subcontinent, stopped after the 12th century. As Hindu kingdoms fell in the eastern and
8614-499: The 1980s. No consensus exists on capitalization. Various publications refer to lidar as "LIDAR", "LiDAR", "LIDaR", or "Lidar". The USGS uses both "LIDAR" and "lidar", sometimes in the same document; the New York Times predominantly uses "lidar" for staff-written articles, although contributing news feeds such as Reuters may use Lidar. Lidar uses ultraviolet , visible , or near infrared light to image objects. It can target
8760-560: The 1st century BCE, such as the Ayodhya Inscription of Dhana and Ghosundi-Hathibada (Chittorgarh) . Though developed and nurtured by scholars of orthodox schools of Hinduism, Sanskrit has been the language for some of the key literary works and theology of heterodox schools of Indian philosophies such as Buddhism and Jainism. The structure and capabilities of the Classical Sanskrit language launched ancient Indian speculations about "the nature and function of language", what
8906-521: The 7th century where he established a major center of learning and language translation under the patronage of Emperor Taizong. By the early 1st millennium CE, Sanskrit had spread Buddhist and Hindu ideas to Southeast Asia, parts of the East Asia and the Central Asia. It was accepted as a language of high culture and the preferred language by some of the local ruling elites in these regions. According to
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#17331225971219052-521: The Dravidian languages borrowed from Sanskrit vocabulary, but they have also affected Sanskrit on deeper levels of structure, "for instance in the domain of phonology where Indo-Aryan retroflexes have been attributed to Dravidian influence". Similarly, Ferenc Ruzca states that all the major shifts in Indo-Aryan phonetics over two millennia can be attributed to the constant influence of a Dravidian language with
9198-513: The Dravidian words and forms, without modifying the word order; but the same thing is not possible in rendering a Persian or English sentence into a non-Indo-Aryan language. Shulman mentions that "Dravidian nonfinite verbal forms (called vinaiyeccam in Tamil) shaped the usage of the Sanskrit nonfinite verbs (originally derived from inflected forms of action nouns in Vedic). This particularly salient case of
9344-480: The Hinayana) but the Prakrit works that have survived are of doubtful authenticity. Some of the canonical fragments of the early Buddhist traditions, discovered in the 20th century, suggest the early Buddhist traditions used an imperfect and reasonably good Sanskrit, sometimes with a Pali syntax, states Renou. The Mahāsāṃghika and Mahavastu, in their late Hinayana forms, used hybrid Sanskrit for their literature. Sanskrit
9490-469: The Indo-Aryan language underwent rapid linguistic change and morphed into the Vedic Sanskrit language. The pre-Classical form of Sanskrit is known as Vedic Sanskrit . The earliest attested Sanskrit text is the Rigveda , a Hindu scripture from the mid- to late-second millennium BCE. No written records from such an early period survive, if any ever existed, but scholars are generally confident that
9636-507: The Indo-European languages are the Nuristani languages found in the remote Hindu Kush region of northeastern Afghanistan and northwestern Himalayas, as well as the extinct Avestan and Old Persian – both are Iranian languages . Sanskrit belongs to the satem group of the Indo-European languages. Colonial era scholars familiar with Latin and Greek were struck by the resemblance of
9782-521: The Muslim rule in the form of Sultanates, and later the Mughal Empire . Sheldon Pollock characterises the decline of Sanskrit as a long-term "cultural, social, and political change". He dismisses the idea that Sanskrit declined due to "struggle with barbarous invaders", and emphasises factors such as the increasing attractiveness of vernacular language for literary expression. With the fall of Kashmir around
9928-489: The Muslim rulers. Hindu rulers such as Shivaji of the Maratha Empire , reversed the process, by re-adopting Sanskrit and re-asserting their socio-linguistic identity. After Islamic rule disintegrated in South Asia and the colonial rule era began, Sanskrit re-emerged but in the form of a "ghostly existence" in regions such as Bengal. This decline was the result of "political institutions and civic ethos" that did not support
10074-488: The Saṃskṛta language, both in its vocabulary and grammar, to the classical languages of Europe. In The Oxford Introduction to Proto-Indo-European and the Proto-Indo-European World , Mallory and Adams illustrate the resemblance with the following examples of cognate forms (with the addition of Old English for further comparison): The correspondences suggest some common root, and historical links between some of
10220-616: The South India, such as the great Vijayanagara Empire , so did Sanskrit. There were exceptions and short periods of imperial support for Sanskrit, mostly concentrated during the reign of the tolerant Mughal emperor Akbar . Muslim rulers patronized the Middle Eastern language and scripts found in Persia and Arabia, and the Indians linguistically adapted to this Persianization to gain employment with
10366-447: The Vedic Sanskrit in these books of the Ṛg-veda "hardly presents any dialectical diversity", states Louis Renou – an Indologist known for his scholarship of the Sanskrit literature and the Ṛg-veda in particular. According to Renou, this implies that the Vedic Sanskrit language had a "set linguistic pattern" by the second half of the 2nd millennium BCE. Beyond the Ṛg-veda, the ancient literature in Vedic Sanskrit that has survived into
10512-451: The Vedic Sanskrit's bahulam framework, to respect liberty and creativity so that individual writers separated by geography or time would have the choice to express facts and their views in their own way, where tradition followed competitive forms of the Sanskrit language. The phonetic differences between Vedic Sanskrit and Classical Sanskrit, as discerned from the current state of the surviving literature, are negligible when compared to
10658-455: The alphabet, the structure of words, and its exacting grammar into a "collection of sounds, a kind of sublime musical mold" as an integral language they called Saṃskṛta . From the late Vedic period onwards, state Annette Wilke and Oliver Moebus, resonating sound and its musical foundations attracted an "exceptionally large amount of linguistic, philosophical and religious literature" in India. Sound
10804-489: The atmosphere. Indeed, lidar has since been used extensively for atmospheric research and meteorology . Lidar instruments fitted to aircraft and satellites carry out surveying and mapping – a recent example being the U.S. Geological Survey Experimental Advanced Airborne Research Lidar. NASA has identified lidar as a key technology for enabling autonomous precision safe landing of future robotic and crewed lunar-landing vehicles. Wavelengths vary to suit
10950-440: The capacity to understand the old Prakrit languages such as Ardhamagadhi . A section of European scholars state that Sanskrit was never a spoken language. However, evidences shows that Sanskrit was a spoken language, essential for oral tradition that preserved the vast number of Sanskrit manuscripts from ancient India. The textual evidence in the works of Yaksa, Panini, and Patanajali affirms that Classical Sanskrit in their era
11096-831: The captured frames do not need to be stitched together, and the system is not sensitive to platform motion. This results in less distortion. 3-D imaging can be achieved using both scanning and non-scanning systems. "3-D gated viewing laser radar" is a non-scanning laser ranging system that applies a pulsed laser and a fast gated camera. Research has begun for virtual beam steering using Digital Light Processing (DLP) technology. Imaging lidar can also be performed using arrays of high speed detectors and modulation sensitive detector arrays typically built on single chips using complementary metal–oxide–semiconductor (CMOS) and hybrid CMOS/ Charge-coupled device (CCD) fabrication techniques. In these devices each pixel performs some local processing such as demodulation or gating at high speed, downconverting
11242-420: The city at a resolution of 30 cm (1 ft), displaying the precise height of rubble strewn in city streets. The new system is ten times better, and could produce much larger maps more quickly. The chip uses indium gallium arsenide (InGaAs), which operates in the infrared spectrum at a relatively long wavelength that allows for higher power and longer ranges. In many applications, such as self-driving cars,
11388-517: The close relationship between the Indo-Iranian tongues and the Baltic and Slavic languages , vocabulary exchange with the non-Indo-European Uralic languages , and the nature of the attested Indo-European words for flora and fauna. The pre-history of Indo-Aryan languages which preceded Vedic Sanskrit is unclear and various hypotheses place it over a fairly wide limit. According to Thomas Burrow, based on
11534-609: The context of a speech or language, is found in verses 5.28.17–19 of the Ramayana . Outside the learned sphere of written Classical Sanskrit, vernacular colloquial dialects ( Prakrits ) continued to evolve. Sanskrit co-existed with numerous other Prakrit languages of ancient India. The Prakrit languages of India also have ancient roots and some Sanskrit scholars have called these Apabhramsa , literally 'spoiled'. The Vedic literature includes words whose phonetic equivalent are not found in other Indo-European languages but which are found in
11680-639: The crystallization of Classical Sanskrit. As in this period the Indo-Aryan tribes had not yet made contact with the inhabitants of the South of the subcontinent, this suggests a significant presence of Dravidian speakers in North India (the central Gangetic plain and the classical Madhyadeśa) who were instrumental in this substratal influence on Sanskrit. Extant manuscripts in Sanskrit number over 30 million, one hundred times those in Greek and Latin combined, constituting
11826-461: The data and is supported by existing workflows that support interpretation of 3-D point clouds . Recent studies investigated voxelisation . The intensities of the waveform samples are inserted into a voxelised space (3-D grayscale image) building up a 3-D representation of the scanned area. Related metrics and information can then be extracted from that voxelised space. Structural information can be extracted using 3-D metrics from local areas and there
11972-546: The data's purpose, the size of the area to be captured, the range of measurement desired, the cost of equipment, and more. Spaceborne platforms are also possible, see satellite laser altimetry . Airborne lidar (also airborne laser scanning ) is when a laser scanner, while attached to an aircraft during flight, creates a 3-D point cloud model of the landscape. This is currently the most detailed and accurate method of creating digital elevation models , replacing photogrammetry . One major advantage in comparison with photogrammetry
12118-467: The detailed and sophisticated treatise then transmitted it through his students. Modern scholarship generally accepts that he knew of a form of writing, based on references to words such as Lipi ('script') and lipikara ('scribe') in section 3.2 of the Aṣṭādhyāyī . The Classical Sanskrit language formalized by Pāṇini, states Renou, is "not an impoverished language", rather it is "a controlled and
12264-467: The differences between the Vedic and Classical Sanskrit. Louis Renou published in 1956, in French, a more extensive discussion of the similarities, the differences and the evolution of the Vedic Sanskrit within the Vedic period and then to the Classical Sanskrit along with his views on the history. This work has been translated by Jagbans Balbir. The earliest known use of the word Saṃskṛta (Sanskrit), in
12410-456: The distant major ancient languages of the world. The Indo-Aryan migrations theory explains the common features shared by Sanskrit and other Indo-European languages by proposing that the original speakers of what became Sanskrit arrived in South Asia from a region of common origin, somewhere north-west of the Indus region , during the early 2nd millennium BCE. Evidence for such a theory includes
12556-451: The dominant language of Hindu texts has been Sanskrit. It or a hybrid form of Sanskrit became the preferred language of Mahayana Buddhism scholarship; for example, one of the early and influential Buddhist philosophers, Nagarjuna (~200 CE), used Classical Sanskrit as the language for his texts. According to Renou, Sanskrit had a limited role in the Theravada tradition (formerly known as
12702-483: The early medieval era, it became a language of religion and high culture , and of the political elites in some of these regions. As a result, Sanskrit had a lasting impact on the languages of South Asia, Southeast Asia and East Asia, especially in their formal and learned vocabularies. Sanskrit generally connotes several Old Indo-Aryan language varieties. The most archaic of these is the Vedic Sanskrit found in
12848-502: The electric helicopter configuration superior at low ranges, and the tilt-wing configuration superior at longer ranges. The designer has not finalized the Vahana project and hope that "the electric tilt-wing configuration provides a DOC advantage and many other advantages such as reduced noise and enhanced safety for urban mobility". For both vehicles a common payload weight will be 200 lb (90 kg). A helicopter gearbox power density
12994-412: The entire field of view is illuminated with a wide diverging laser beam in a single pulse. This is in contrast to conventional scanning lidar, which uses a collimated laser beam that illuminates a single point at a time, and the beam is raster scanned to illuminate the field of view point-by-point. This illumination method requires a different detection scheme as well. In both scanning and flash lidar,
13140-408: The entire scene is illuminated at the same time. With scanning lidar, motion can cause "jitter" from the lapse in time as the laser rasters over the scene. As with all forms of lidar, the onboard source of illumination makes flash lidar an active sensor. The signal that is returned is processed by embedded algorithms to produce a nearly instantaneous 3-D rendering of objects and terrain features within
13286-514: The field of view of the sensor. The laser pulse repetition frequency is sufficient for generating 3-D videos with high resolution and accuracy. The high frame rate of the sensor makes it a useful tool for a variety of applications that benefit from real-time visualization, such as highly precise remote landing operations. By immediately returning a 3-D elevation mesh of target landscapes, a flash sensor can be used to identify optimal landing zones in autonomous spacecraft landing scenarios. Seeing at
13432-543: The first language of the respective speakers. The Sanskrit language brought Indo-Aryan speaking people together, particularly its elite scholars. Some of these scholars of Indian history regionally produced vernacularized Sanskrit to reach wider audiences, as evidenced by texts discovered in Rajasthan, Gujarat, and Maharashtra. Once the audience became familiar with the easier to understand vernacularized version of Sanskrit, those interested could graduate from colloquial Sanskrit to
13578-412: The foundation of Vyākaraṇa, a Vedānga . The Aṣṭādhyāyī was not the first description of Sanskrit grammar, but it is the earliest that has survived in full, and the culmination of a long grammatical tradition that Fortson says, is "one of the intellectual wonders of the ancient world". Pāṇini cites ten scholars on the phonological and grammatical aspects of the Sanskrit language before him, as well as
13724-476: The gods Varuna, Mitra, Indra, and Nasatya found in the earliest layers of the Vedic literature. O Bṛhaspati, when in giving names they first set forth the beginning of Language, Their most excellent and spotless secret was laid bare through love, When the wise ones formed Language with their mind, purifying it like grain with a winnowing fan, Then friends knew friendships – an auspicious mark placed on their language. The Vedic Sanskrit found in
13870-471: The ground the non-vegetation data is obtained which may include objects such as buildings, electric power lines, flying birds, insects, etc. The rest of the points are treated as vegetation and used for modeling and mapping. Within each of these plots, lidar metrics are calculated by calculating statistics such as mean, standard deviation, skewness, percentiles, quadratic mean, etc. Multiple commercial lidar systems for unmanned aerial vehicles are currently on
14016-431: The historic Sanskrit literary culture and the failure of new Sanskrit literature to assimilate into the changing cultural and political environment. Sheldon Pollock states that in some crucial way, "Sanskrit is dead ". After the 12th century, the Sanskrit literary works were reduced to "reinscription and restatements" of ideas already explored, and any creativity was restricted to hymns and verses. This contrasted with
14162-478: The intense change that must have occurred in the pre-Vedic period between the Proto-Indo-Aryan language and Vedic Sanskrit. The noticeable differences between the Vedic and the Classical Sanskrit include the much-expanded grammar and grammatical categories as well as the differences in the accent, the semantics and the syntax. There are also some differences between how some of the nouns and verbs end, as well as
14308-408: The intensity of the returned signal. The name "photonic radar" is sometimes used to mean visible-spectrum range finding like lidar, although photonic radar more strictly refers to radio-frequency range finding using photonics components. A lidar determines the distance of an object or a surface with the formula : where c is the speed of light , d is the distance between the detector and
14454-459: The largest cultural heritage that any civilization has produced prior to the invention of the printing press. Sanskrit has been the predominant language of Hindu texts encompassing a rich tradition of philosophical and religious texts, as well as poetry, music, drama , scientific , technical and others. It is the predominant language of one of the largest collection of historic manuscripts. The earliest known inscriptions in Sanskrit are from
14600-540: The laser is limited, or an automatic shut-off system which turns the laser off at specific altitudes is used in order to make it eye-safe for the people on the ground. One common alternative, 1,550 nm lasers, are eye-safe at relatively high power levels since this wavelength is not strongly absorbed by the eye. A trade-off though is that current detector technology is less advanced, so these wavelengths are generally used at longer ranges with lower accuracies. They are also used for military applications because 1,550 nm
14746-441: The laser repetition rate (which controls the data collection speed). Pulse length is generally an attribute of the laser cavity length, the number of passes required through the gain material (YAG, YLF , etc.), and Q-switch (pulsing) speed. Better target resolution is achieved with shorter pulses, provided the lidar receiver detectors and electronics have sufficient bandwidth. A phased array can illuminate any direction by using
14892-659: The laser, typically on the order of one microjoule , and are often "eye-safe", meaning they can be used without safety precautions. High-power systems are common in atmospheric research, where they are widely used for measuring atmospheric parameters: the height, layering and densities of clouds, cloud particle properties ( extinction coefficient , backscatter coefficient, depolarization ), temperature, pressure, wind, humidity, and trace gas concentration (ozone, methane, nitrous oxide , etc.). Lidar systems consist of several major components. 600–1,000 nm lasers are most common for non-scientific applications. The maximum power of
15038-412: The linguistic expression and sets the standard for the Sanskrit language. Pāṇini made use of a technical metalanguage consisting of a syntax, morphology and lexicon. This metalanguage is organised according to a series of meta-rules, some of which are explicitly stated while others can be deduced. Despite differences in the analysis from that of modern linguistics, Pāṇini's work has been found valuable and
15184-503: The literary works. The Indian tradition, states Winternitz , has favored the learning and the usage of multiple languages from the ancient times. Sanskrit was a spoken language in the educated and the elite classes, but it was also a language that must have been understood in a wider circle of society because the widely popular folk epics and stories such as the Ramayana , the Mahabharata ,
15330-415: The major sea floor mapping program. The mapping yields onshore topography as well as underwater elevations. Sea floor reflectance imaging is another solution product from this system which can benefit mapping of underwater habitats. This technique has been used for three-dimensional image mapping of California's waters using a hydrographic lidar. Airborne lidar systems were traditionally able to acquire only
15476-464: The market. These platforms can systematically scan large areas, or provide a cheaper alternative to manned aircraft for smaller scanning operations. The airborne lidar bathymetric technological system involves the measurement of time of flight of a signal from a source to its return to the sensor. The data acquisition technique involves a sea floor mapping component and a ground truth component that includes video transects and sampling. It works using
15622-620: The maximum depth. Turbidity causes scattering and has a significant role in determining the maximum depth that can be resolved in most situations, and dissolved pigments can increase absorption depending on wavelength. Other reports indicate that water penetration tends to be between two and three times Secchi depth. Bathymetric lidar is most useful in the 0–10 m (0–33 ft) depth range in coastal mapping. On average in fairly clear coastal seawater lidar can penetrate to about 7 m (23 ft), and in turbid water up to about 3 m (10 ft). An average value found by Saputra et al, 2021,
15768-501: The modern age include the Samaveda , Yajurveda , Atharvaveda , along with the embedded and layered Vedic texts such as the Brahmanas , Aranyakas , and the early Upanishads . These Vedic documents reflect the dialects of Sanskrit found in the various parts of the northwestern, northern, and eastern Indian subcontinent. According to Michael Witzel, Vedic Sanskrit was a spoken language of
15914-429: The more advanced Classical Sanskrit. Rituals and the rites-of-passage ceremonies have been and continue to be the other occasions where a wide spectrum of people hear Sanskrit, and occasionally join in to speak some Sanskrit words such as namah . Classical Sanskrit is the standard register as laid out in the grammar of Pāṇini , around the fourth century BCE. Its position in the cultures of Greater India
16060-401: The most advanced analysis of linguistics until the twentieth century. Pāṇini's comprehensive and scientific theory of grammar is conventionally taken to mark the start of Classical Sanskrit. His systematic treatise inspired and made Sanskrit the preeminent Indian language of learning and literature for two millennia. It is unclear whether Pāṇini himself wrote his treatise or he orally created
16206-593: The most archaic poems of the Iranian and Greek language families, the Gathas of old Avestan and Iliad of Homer . As the Rigveda was orally transmitted by methods of memorisation of exceptional complexity, rigour and fidelity, as a single text without variant readings, its preserved archaic syntax and morphology are of vital importance in the reconstruction of the common ancestor language Proto-Indo-European . Sanskrit does not have an attested native script: from around
16352-400: The new system will lower costs by not requiring a mechanical component to aim the chip. InGaAs uses less hazardous wavelengths than conventional silicon detectors, which operate at visual wavelengths. New technologies for infrared single-photon counting LIDAR are advancing rapidly, including arrays and cameras in a variety of semiconductor and superconducting platforms. In flash lidar,
16498-583: The numbers are thought to signify a wish to be aligned with the prestige of the language. Sanskrit has been taught in traditional gurukulas since ancient times; it is widely taught today at the secondary school level. The oldest Sanskrit college is the Benares Sanskrit College founded in 1791 during East India Company rule . Sanskrit continues to be widely used as a ceremonial and ritual language in Hindu and Buddhist hymns and chants . In Sanskrit,
16644-402: The object or surface being detected, and t is the time spent for the laser light to travel to the object or surface being detected, then travel back to the detector. The two kinds of lidar detection schemes are "incoherent" or direct energy detection (which principally measures amplitude changes of the reflected light) and coherent detection (best for measuring Doppler shifts, or changes in
16790-403: The oral transmission of the texts is reliable: they are ceremonial literature, where the exact phonetic expression and its preservation were a part of the historic tradition. However some scholars have suggested that the original Ṛg-veda differed in some fundamental ways in phonology compared to the sole surviving version available to us. In particular that retroflex consonants did not exist as
16936-431: The other." Reinöhl further states that there is a symmetric relationship between Dravidian languages like Kannada or Tamil, with Indo-Aryan languages like Bengali or Hindi, whereas the same relationship is not found for non-Indo-Aryan languages, for example, Persian or English: A sentence in a Dravidian language like Tamil or Kannada becomes ordinarily good Bengali or Hindi by substituting Bengali or Hindi equivalents for
17082-504: The phase of the reflected light). Coherent systems generally use optical heterodyne detection . This is more sensitive than direct detection and allows them to operate at much lower power, but requires more complex transceivers. Both types employ pulse models: either micropulse or high energy . Micropulse systems utilize intermittent bursts of energy. They developed as a result of ever-increasing computer power, combined with advances in laser technology. They use considerably less energy in
17228-414: The possible influence of Dravidian on Sanskrit is only one of many items of syntactic assimilation, not least among them the large repertoire of morphological modality and aspect that, once one knows to look for it, can be found everywhere in classical and postclassical Sanskrit". The main influence of Dravidian on Sanskrit is found to have been concentrated in the timespan between the late Vedic period and
17374-439: The previous 1,500 years when "great experiments in moral and aesthetic imagination" marked the Indian scholarship using Classical Sanskrit, states Pollock. Scholars maintain that the Sanskrit language did not die, but rather only declined. Jurgen Hanneder disagrees with Pollock, finding his arguments elegant but "often arbitrary". According to Hanneder, a decline or regional absence of creative and innovative literature constitutes
17520-480: The problems of interpretation and misunderstanding. The purifying structure of the Sanskrit language removes these imperfections. The early Sanskrit grammarian Daṇḍin states, for example, that much in the Prakrit languages is etymologically rooted in Sanskrit, but involves "loss of sounds" and corruptions that result from a "disregard of the grammar". Daṇḍin acknowledged that there are words and confusing structures in Prakrit that thrive independent of Sanskrit. This view
17666-463: The reflected energy is detected and measured by sensors. Distance to the object is determined by recording the time between transmitted and backscattered pulses and by using the speed of light to calculate the distance traveled. Flash lidar allows for 3-D imaging because of the camera's ability to emit a larger flash and sense the spatial relationships and dimensions of area of interest with the returned energy. This allows for more accurate imaging because
17812-596: The regional Prakrit languages, which makes it likely that the interaction, the sharing of words and ideas began early in the Indian history. As the Indian thought diversified and challenged earlier beliefs of Hinduism, particularly in the form of Buddhism and Jainism , the Prakrit languages such as Pali in Theravada Buddhism and Ardhamagadhi in Jainism competed with Sanskrit in the ancient times. However, states Paul Dundas , these ancient Prakrit languages had "roughly
17958-490: The relationship between various Indo-European languages, the origin of all these languages may possibly be in what is now Central or Eastern Europe, while the Indo-Iranian group possibly arose in Central Russia. The Iranian and Indo-Aryan branches separated quite early. It is the Indo-Aryan branch that moved into eastern Iran and then south into South Asia in the first half of the 2nd millennium BCE. Once in ancient India,
18104-438: The rites-of-passage. Similarly, Brian Hatcher states that the "metaphors of historical rupture" by Pollock are not valid, that there is ample proof that Sanskrit was very much alive in the narrow confines of surviving Hindu kingdoms between the 13th and 18th centuries, and its reverence and tradition continues. Hanneder states that modern works in Sanskrit are either ignored or their "modernity" contested. Lidar Lidar
18250-491: The same relationship to Sanskrit as medieval Italian does to Latin". The Indian tradition states that the Buddha and the Mahavira preferred the Prakrit language so that everyone could understand it. However, scholars such as Dundas have questioned this hypothesis. They state that there is no evidence for this and whatever evidence is available suggests that by the start of the common era, hardly anybody other than learned monks had
18396-562: The scale required of Urban Air Mobility." Then-CEO Tom Enders said: "I'm no big fan of Star Wars, but it's not crazy to imagine that one day our big cities will have flying cars making their way along roads in the sky." To test the Vahana concept, small models flew in Santa Clara , USA in 2017. Vahana was planned to become part of urban air mobility. In June 2017 at the Paris Air Show the prototype Vahana Alpha One (registration N301VX )
18542-401: The scanned area from the scanner's location to create realistic looking 3-D models in a relatively short time when compared to other technologies. Each point in the point cloud is given the colour of the pixel from the image taken at the same location and direction as the laser beam that created the point. Mobile lidar (also mobile laser scanning ) is when two or more scanners are attached to
18688-551: The semi-nomadic Aryans . The Vedic Sanskrit language or a closely related Indo-European variant was recognized beyond ancient India as evidenced by the " Mitanni Treaty" between the ancient Hittite and Mitanni people, carved into a rock, in a region that now includes parts of Syria and Turkey. Parts of this treaty, such as the names of the Mitanni princes and technical terms related to horse training, for reasons not understood, are in early forms of Vedic Sanskrit. The treaty also invokes
18834-463: The signals to video rate so that the array can be read like a camera. Using this technique many thousands of pixels / channels may be acquired simultaneously. High resolution 3-D lidar cameras use homodyne detection with an electronic CCD or CMOS shutter . A coherent imaging lidar uses synthetic array heterodyne detection to enable a staring single element receiver to act as though it were an imaging array. In 2014, Lincoln Laboratory announced
18980-594: The social structures such as the role of the poet and the priests, the patronage economy, the phrasal equations, and some of the poetic metres. While there are similarities, state Jamison and Brereton, there are also differences between Vedic Sanskrit, the Old Avestan, and the Mycenaean Greek literature. For example, unlike the Sanskrit similes in the Ṛg-veda, the Old Avestan Gathas lack simile entirely, and it
19126-527: The target: from about 10 micrometers ( infrared ) to approximately 250 nanometers ( ultraviolet ). Typically, light is reflected via backscattering , as opposed to pure reflection one might find with a mirror. Different types of scattering are used for different lidar applications: most commonly Rayleigh scattering , Mie scattering , Raman scattering , and fluorescence . Suitable combinations of wavelengths can allow remote mapping of atmospheric contents by identifying wavelength-dependent changes in
19272-449: The term " radar ", itself an acronym for "radio detection and ranging". All laser rangefinders , laser altimeters and lidar units are derived from the early colidar systems. The first practical terrestrial application of a colidar system was the "Colidar Mark II", a large rifle-like laser rangefinder produced in 1963, which had a range of 11 km and an accuracy of 4.5 m, to be used for military targeting. The first mention of lidar as
19418-641: The turn of the 1st-millennium CE, it has been written in various Brahmic scripts , and in the modern era most commonly in Devanagari . Sanskrit's status, function, and place in India's cultural heritage are recognized by its inclusion in the Constitution of India 's Eighth Schedule languages . However, despite attempts at revival, there are no first-language speakers of Sanskrit in India. In each of India's recent decennial censuses, several thousand citizens have reported Sanskrit to be their mother tongue, but
19564-408: The variants in the usage of Sanskrit in different regions of India. The ten Vedic scholars he quotes are Āpiśali, Kaśyapa , Gārgya, Gālava, Cakravarmaṇa, Bhāradvāja , Śākaṭāyana, Śākalya, Senaka and Sphoṭāyana. In the Aṣṭādhyāyī , language is observed in a manner that has no parallel among Greek or Latin grammarians. Pāṇini's grammar, according to Renou and Filliozat, is a classic that defines
19710-495: The vectors of discrete points while DEM and DSM are interpolated raster grids of discrete points. The process also involves capturing of digital aerial photographs. To interpret deep-seated landslides for example, under the cover of vegetation, scarps, tension cracks or tipped trees airborne lidar is used. Airborne lidar digital elevation models can see through the canopy of forest cover, perform detailed measurements of scarps, erosion and tilting of electric poles. Airborne lidar data
19856-564: The vernacular Prakrits. Many Sanskrit dramas indicate that the language coexisted with the vernacular Prakrits. The cities of Varanasi , Paithan , Pune and Kanchipuram were centers of classical Sanskrit learning and public debates until the arrival of the colonial era. According to Lamotte , Sanskrit became the dominant literary and inscriptional language because of its precision in communication. It was, states Lamotte, an ideal instrument for presenting ideas, and as knowledge in Sanskrit multiplied, so did its spread and influence. Sanskrit
20002-429: The wavelength of light. It has also been increasingly used in control and navigation for autonomous cars and for the helicopter Ingenuity on its record-setting flights over the terrain of Mars . The evolution of quantum technology has given rise to the emergence of Quantum Lidar, demonstrating higher efficiency and sensitivity when compared to conventional lidar systems. Under the direction of Malcolm Stitch,
20148-497: The Ṛg-veda is distinctly more archaic than other Vedic texts, and in many respects, the Rigvedic language is notably more similar to those found in the archaic texts of Old Avestan Zoroastrian Gathas and Homer's Iliad and Odyssey . According to Stephanie W. Jamison and Joel P. Brereton – Indologists known for their translation of the Ṛg-veda – the Vedic Sanskrit literature "clearly inherited" from Indo-Iranian and Indo-European times
20294-408: Was a spoken language ( bhasha ) used by the cultured and educated. Some sutras expound upon the variant forms of spoken Sanskrit versus written Sanskrit. Chinese Buddhist pilgrim Xuanzang mentioned in his memoir that official philosophical debates in India were held in Sanskrit, not in the vernacular language of that region. According to Sanskrit linguist professor Madhav Deshpande, Sanskrit
20440-427: Was a spoken language in a colloquial form by the mid-1st millennium BCE which coexisted with a more formal, grammatically correct form of literary Sanskrit. This, states Deshpande, is true for modern languages where colloquial incorrect approximations and dialects of a language are spoken and understood, along with more "refined, sophisticated and grammatically accurate" forms of the same language being found in
20586-472: Was adopted voluntarily as a vehicle of high culture, arts, and profound ideas. Pollock disagrees with Lamotte, but concurs that Sanskrit's influence grew into what he terms a "Sanskrit Cosmopolis" over a region that included all of South Asia and much of southeast Asia. The Sanskrit language cosmopolis thrived beyond India between 300 and 1300 CE. Today, it is believed that Kashmiri is the closest language to Sanskrit. Reinöhl mentions that not only have
20732-722: Was also the language of some of the oldest surviving, authoritative and much followed philosophical works of Jainism such as the Tattvartha Sutra by Umaswati . The Sanskrit language has been one of the major means for the transmission of knowledge and ideas in Asian history. Indian texts in Sanskrit were already in China by 402 CE, carried by the influential Buddhist pilgrim Faxian who translated them into Chinese by 418 CE. Xuanzang , another Chinese Buddhist pilgrim, learnt Sanskrit in India and carried 657 Sanskrit texts to China in
20878-490: Was being developed as a self-steering aircraft was because the developers expected the available human pilots would not be sufficient in number for the anticipated volume of flights. Another reason was the higher payload and saving on labour expenses. In contrast to autonomous driving, autonomous flying has to be navigated at a significantly higher speed and in three instead of two dimensions. This requires higher computing speed and faster sensors and actuators. Autonomous navigation
21024-456: Was publicly presented for the first time. 31 January 2018 the first flight took place in Pendleton, Oregon . The full-scale aircraft Alpha One demonstrator reached a height of 5 meters within 53 seconds. By August 2018, more than 25 hover flights had been completed and the transition to forward flight had been tested. By January 2019, the second aircraft, Alpha Two, was completed, while the first
21170-530: Was testing transitions to forward flight, but was not yet flown with the wings horizontal. On 3 May, it achieved its first full transitions to forward flight, reaching 90 kn (170 km/h) on its 58th flight. Airbus will not produce serial versions of the Vahana or the ducted-rotor CityAirbus demonstrators. Airbus finished the Vahana project in December 2019 in favor of the CityAirbus. The last flight took place on 14 November 2019, after 138 test flights with
21316-442: Was visualized as "pervading all creation", another representation of the world itself; the "mysterious magnum" of Hindu thought. The search for perfection in thought and the goal of liberation were among the dimensions of sacred sound, and the common thread that wove all ideas and inspirations together became the quest for what the ancient Indians believed to be a perfect language, the "phonocentric episteme" of Sanskrit. Sanskrit as
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