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45-512: Starting around 1996 the California-based company Octavo began scanning rare and important books from libraries around the world. These scans were done at extremely high resolution using high-quality equipment, with some pages at over 200MB each. They were sold by Octavo as commercial products on CD-ROM. In 2006 the "Rare Book Room" website was created which contains the complete collection in medium to medium-high resolution freely available to

90-466: A 4K display with a pixel density of 807 PPI, the highest of any smartphone as of 2017. Android supports the following logical DPI values for controlling how large content is displayed: The digital publishing industry primarily uses pixels per inch but sometimes pixels per centimeter is used, or a conversion factor is given. The PNG image file format only allows the meter as the unit for pixel density. The following table show how pixel density

135-455: A 0.44 inch (1.12 cm) SVGA LCD with a pixel density of 2272 PPI (each pixel only 11.25   μm). In 2011 they followed this up with a 3760-DPI 0.21-inch diagonal VGA colour display. The manufacturer says they designed the LCD to be optically magnified, as in high-resolution eyewear devices. Holography applications demand even greater pixel density, as higher pixel density produces

180-407: A 3.1-megapixel image. The image would be a very low quality image (72ppi) if printed at about 28.5 inches wide, but a very good quality (300ppi) image if printed at about 7 inches wide. The number of photodiodes in a color digital camera image sensor is often a multiple of the number of pixels in the image it produces, because information from an array of color image sensors is used to reconstruct

225-477: A different way to a bright, evenly lit interactive display from how it does to prints on paper. High pixel density display technologies would make supersampled antialiasing obsolete, enable true WYSIWYG graphics and, potentially enable a practical “ paperless office ” era. For perspective, such a device at 15 inch (38 cm) screen size would have to display more than four Full HD screens (or WQUXGA resolution). The PPI pixel density specification of

270-621: A display is also useful for calibrating a monitor with a printer. Software can use the PPI measurement to display a document at "actual size" on the screen. PPI can be calculated from the screen's diagonal size in inches and the resolution in pixels (width and height). This can be done in two steps: where For example: These calculations may not be very precise. Frequently, screens advertised as “X inch screen” can have their real physical dimensions of viewable area differ, for example: Camera manufacturers often quote view screens in 'number of dots'. This

315-399: A format and the pixels per inch of the output: Pixels per inch (or pixels per centimetre) describes the detail of an image file when the print size is known. For example, a 100×100 pixel image printed in a 2 inch square has a resolution of 50 pixels per inch. Used this way, the measurement is meaningful when printing an image. In many applications, such as Adobe Photoshop, the program

360-400: A large format. Printing on paper is accomplished with different technologies. Newspapers and magazines were traditionally printed using a halftone screen, which would print dots at a given frequency, the screen frequency, in lines per inch (LPI) by using a purely analog process in which a photographic print is converted into variable sized dots through interference patterns passing through

405-404: A larger image size and wider viewing angle. Spatial light modulators can reduce pixel pitch to 2.5  μm , giving a pixel density of 10,160 PPI. Some observations indicate that the unaided human generally can't differentiate detail beyond 300 PPI. However, this figure depends both on the distance between viewer and image, and the viewer’s visual acuity . The human eye also responds in

450-587: A lower PPI than a compact camera, because it has larger photodiodes due to having far larger sensors. Smartphones use small displays, but modern smartphone displays have a larger PPI rating, such as the Samsung Galaxy S7 with a quad HD display at 577 PPI, Fujitsu F-02G with a quad HD display at 564 PPI, the LG G6 with quad HD display at 564 PPI or – XHDPI or Oppo Find 7 with 534 PPI on 5.5-inch display – XXHDPI (see section below). Sony 's Xperia XZ Premium has

495-423: A new image at this monitor resolution of 1920 pixels, possibly intended for the web without regard to printing. Rewriting the formula above can tell us the pixel density (PPI) of the image on the monitor display: Now, let us imagine the artist wishes to print a larger banner at 48″ horizontally. We know the number of pixels in the image, and the size of the output, from which we can use the same formula again to give

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540-421: A particle's coordinates imposed by the measurement or existence of information regarding its momentum to any degree of precision. This fundamental limitation can, in turn, be a factor in the maximum imaging resolution at subatomic scales, as can be encountered using scanning electron microscopes . Radiometric resolution determines how finely a system can represent or distinguish differences of intensity , and

585-529: A picture (lines per picture height, also known simply as lines, TV lines, or TVL), or to angular subtense. Instead of single lines, line pairs are often used, composed of a dark line and an adjacent light line; for example, a resolution of 10 lines per millimeter means 5 dark lines alternating with 5 light lines, or 5 line pairs per millimeter (5 LP/mm). Photographic lens are most often quoted in line pairs per millimeter. The resolution of digital cameras can be described in many different ways. The term resolution

630-482: A print can be viewed close up, then one may choose the printer device limits. However, if a poster, banner or billboard will be viewed from far away then it is possible to use a much lower PPI. The PPI/PPCM of a computer display is related to the size of the display in inches / centimetres and the total number of pixels in the horizontal and vertical directions. This measurement is often referred to as dots per inch , though that measurement more accurately refers to

675-474: A printer capable of 600 dpi could be created at 300 ppi. When using other technologies such as AM or FM screen printing, there are often published screening charts that indicate the ideal PPI for a printing method. Using the DPI or LPI of a printer remains useful to determine PPI until one reaches larger formats, such as 36" or higher, as the factor of visual acuity then becomes more important to consider. If

720-410: A process called dithering . The dot pitch , smallest size of each dot, is also determined by the type of paper the image is printed on. An absorbent paper surface, uncoated recycled paper for instance, lets ink droplets spread — so has a larger dot pitch. Often one wishes to know the image quality in pixels per inch (PPI) that would be suitable for a given output device. If the choice is too low, then

765-416: A sample), but when it is printed, displayed, or scanned, then the pixel has both a physical size (dimension) and a pixel density (ppi). Since most digital hardware devices use dots or pixels, the size of the media (in inches) and the number of pixels (or dots) are directly related by the 'pixels per inch'. The following formula gives the number of pixels, horizontally or vertically, given the physical size of

810-414: A screen. Modern inkjet printers can print microscopic dots at any location, and don't require a screen grid, with the metric dots per inch (DPI). These are both different from pixel density or pixels per inch (PPI) because a pixel is a single sample of any color, whereas an inkjet print can only print a dot of a specific color either on or off. Thus a printer translates the pixels into a series of dots using

855-472: Is a list of traditional, analogue horizontal resolutions for various media. The list only includes popular formats, not rare formats, and all values are approximate, because the actual quality can vary machine-to-machine or tape-to-tape. For ease-of-comparison, all values are for the NTSC system. (For PAL systems, replace 480 with 576.) Analog formats usually had less chroma resolution. Many cameras and displays offset

900-474: Is an illustration of how the same image might appear at different pixel resolutions, if the pixels were poorly rendered as sharp squares (normally, a smooth image reconstruction from pixels would be preferred, but for illustration of pixels, the sharp squares make the point better). [REDACTED] An image that is 2048 pixels in width and 1536 pixels in height has a total of 2048×1536 = 3,145,728 pixels or 3.1 megapixels. One could refer to it as 2048 by 1536 or

945-491: Is called spatial resolution, and it depends on properties of the system creating the image, not just the pixel resolution in pixels per inch (ppi). For practical purposes the clarity of the image is decided by its spatial resolution, not the number of pixels in an image. In effect, spatial resolution is the number of independent pixel values per unit length. The spatial resolution of consumer displays ranges from 50 to 800 pixel lines per inch. With scanners, optical resolution

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990-461: Is designed so that one creates new images by specifying the output device and PPI (pixels per inch). Thus the output target is often defined upon creating the image. When moving images between devices, such as printing an image that was created on a monitor, it is important to understand the pixel density of both devices. Consider a 23″ HD monitor (20″ wide), that has a known, native resolution of 1920 pixels (horizontal). Let us assume an artist created

1035-593: Is not the same as the number of pixels, because there are 3 'dots' per pixel – red, green and blue. For example, the Canon 50D is quoted as having 920,000 dots. This translates as 307,200 pixels (×3 = 921,600 dots). Thus the screen is 640×480 pixels. This must be taken into account when working out the PPI. 'Dots' and 'pixels' are often confused in reviews and specs when viewing information about digital cameras specifically. "PPI" or "pixel density" may also describe image scanner resolution. In this context, PPI

1080-409: Is often considered equivalent to pixel count in digital imaging , though international standards in the digital camera field specify it should instead be called "Number of Total Pixels" in relation to image sensors, and as "Number of Recorded Pixels" for what is fully captured. Hence, CIPA DCG-001 calls for notation such as "Number of Recorded Pixels 1000 × 1500". According to the same standards,

1125-541: Is sometimes used to distinguish spatial resolution from the number of pixels per inch. In remote sensing , spatial resolution is typically limited by diffraction , as well as by aberrations, imperfect focus, and atmospheric distortion. The ground sample distance (GSD) of an image, the pixel spacing on the Earth's surface, is typically considerably smaller than the resolvable spot size. In astronomy , one often measures spatial resolution in data points per arcsecond subtended at

1170-435: Is supported by popular image file formats. The cell colors used do not indicate how feature-rich a certain image file format is, but what density support can be expected of a certain image file format. Even though image manipulation software can optionally set density for some image file formats, not many other software uses density information when displaying images. Web browsers, for example, ignore any density information. As

1215-475: Is synonymous with samples per inch . In digital photography, pixel density is the number of pixels divided by the area of the sensor. A typical DSLR , circa 2013, has 1–6.2 MP/cm ; a typical compact has 20–70 MP/cm . For example, Sony Alpha SLT-A58 has 20.1 megapixels on an APS-C sensor having 6.2 MP/cm since a compact camera like Sony Cyber-shot DSC-HX50V has 20.4 megapixels on an 1/2.3" sensor having 70 MP/cm . The professional camera has

1260-407: Is the level of detail of an image . The term applies to digital images, film images, and other types of images. "Higher resolution" means more image detail. Image resolution can be measured in various ways. Resolution quantifies how close lines can be to each other and still be visibly resolved . Resolution units can be tied to physical sizes (e.g. lines per mm, lines per inch), to the overall size of

1305-435: Is the precision of a measurement with respect to time. Movie cameras and high-speed cameras can resolve events at different points in time. The time resolution used for movies is usually 24 to 48 frames per second (frames/s), whereas high-speed cameras may resolve 50 to 300 frames/s, or even more. The Heisenberg uncertainty principle describes the fundamental limit on the maximum spatial resolution of information about

1350-430: Is usually expressed as a number of levels or a number of bits , for example 8 bits or 256 levels that is typical of computer image files. The higher the radiometric resolution, the better subtle differences of intensity or reflectivity can be represented, at least in theory. In practice, the effective radiometric resolution is typically limited by the noise level, rather than by the number of bits of representation. This

1395-627: The First Folio from the Folger Library . It includes Library of Congress copies of Poor Richard's Almanack by Benjamin Franklin , and other rare editions: a Gutenberg Bible of 1455, William Harvey 's book on the circulation of blood , Galileo ’s Sidereus Nuncius , the first printing of the United States Bill of Rights , and Magna Carta . High resolution Image resolution

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1440-479: The "Number of Effective Pixels" that an image sensor or digital camera has is the count of pixel sensors that contribute to the final image (including pixels not in said image but nevertheless support the image filtering process), as opposed to the number of total pixels , which includes unused or light-shielded pixels around the edges. An image of N pixels height by M pixels wide can have any resolution less than N lines per picture height, or N TV lines. But when

1485-430: The PPI of the printed poster: This shows that the output banner will have only 40 pixels per inch. Since a printer device is capable of printing at 300 ppi, the resolution of the original image is well below what would be needed to create a decent quality banner, even if it looked good on a monitor for a website. We would say more directly that a 1920 × 1080 pixel image does not have enough pixels to be printed in

1530-427: The color components relative to each other or mix up temporal with spatial resolution: Pixels per inch Pixels per inch ( ppi ) and pixels per centimetre ( ppcm or pixels/cm ) are measurements of the pixel density of an electronic image device, such as a computer monitor or television display, or image digitizing device such as a camera or image scanner . Horizontal and vertical density are usually

1575-575: The color of a single pixel. The image has to be interpolated or demosaiced to produce all three colors for each output pixel. The terms blurriness and sharpness are used for digital images but other descriptors are used to reference the hardware capturing and displaying the images. Spatial resolution in radiology is the ability of the imaging modality to differentiate two objects. Low spatial resolution techniques will be unable to differentiate between two objects that are relatively close together. The measure of how closely lines can be resolved in an image

1620-403: The display area in pixels by the width (or height) of the display area in inches. It is possible for a display to have different horizontal and vertical PPI measurements (e.g., a typical 4:3 ratio CRT monitor showing a 1280×1024 mode computer display at maximum size, which is a 5:4 ratio, not quite the same as 4:3). The apparent PPI of a monitor depends upon the screen resolution (that is,

1665-408: The hardware capturing and displaying the images. Spectral resolution is the ability to resolve spectral features and bands into their separate components. Color images distinguish light of different spectra . Multispectral images can resolve even finer differences of spectrum or wavelength by measuring and storing more than the traditional 3 of common RGB color images. Temporal resolution (TR)

1710-442: The latter (although more difficult to achieve) is key to visualizing how individual atoms interact. In Stereoscopic 3D images, spatial resolution could be defined as the spatial information recorded or captured by two viewpoints of a stereo camera (left and right camera). Pixel encoding limits the information stored in a digital image, and the term color profile is used for digital images but other descriptors are used to reference

1755-618: The number of pixels) and the size of the screen in use; a monitor in 800×600 mode has a lower PPI than does the same monitor in a 1024×768 or 1280×960 mode. The dot pitch of a computer display determines the absolute limit of possible pixel density. Typical circa-2000 cathode-ray tube or LCD computer displays range from 67 to 130 PPI, though desktop monitors have exceeded 200 PPI, and certain smartphone manufacturers' flagship mobile device models have been exceeding 500 PPI since 2014. In January 2008, Kopin Corporation announced

1800-814: The pixel counts are referred to as "resolution", the convention is to describe the pixel resolution with the set of two positive integer numbers, where the first number is the number of pixel columns (width) and the second is the number of pixel rows (height), for example as 7680 × 6876 . Another popular convention is to cite resolution as the total number of pixels in the image, typically given as number of megapixels , which can be calculated by multiplying pixel columns by pixel rows and dividing by one million. Other conventions include describing pixels per length unit or pixels per area unit, such as pixels per inch or per square inch. None of these pixel resolutions are true resolutions , but they are widely referred to as such; they serve as upper bounds on image resolution. Below

1845-585: The point of observation, because the physical distance between objects in the image depends on their distance away and this varies widely with the object of interest. On the other hand, in electron microscopy , line or fringe resolution is the minimum separation detectable between adjacent parallel lines (e.g. between planes of atoms), whereas point resolution is instead the minimum separation between adjacent points that can be both detected and interpreted e.g. as adjacent columns of atoms, for instance. The former often helps one detect periodicity in specimens, whereas

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1890-700: The public through a web browser or as a PDF file. Some high resolution versions are still being sold by Octavo through a separate website. As of 2007 over 400 books have been scanned. The repository includes books by: It includes most of the Shakespeare Quartos from the British Library , the Bodleian Library , the University of Edinburgh Library, and the National Library of Scotland , as well as

1935-430: The quality will be below what the device is capable of—loss of quality—and if the choice is too high then pixels will be stored unnecessarily—wasted disk space. The ideal pixel density (PPI) depends on the output format, output device, the intended use and artistic choice. For inkjet printers measured in DPI it is generally good practice to use half or less than the DPI to determine the PPI. For example, an image intended for

1980-413: The resolution of a computer printer . For example, a 15-inch (38 cm) display whose dimensions work out to 12 inches (30.48 cm) wide by 9 inches (22.86 cm) high, capable of a maximum 1024×768 (or XGA ) pixel resolution, can display around 85 PPI, or 33.46   PPCM, in both the horizontal and vertical directions. This figure is determined by dividing the width (or height) of

2025-406: The same, as most devices have square pixels , but differ on devices that have non-square pixels. Pixel density is not the same as resolution  —  where the former describes the amount of detail on a physical surface or device, the latter describes the amount of pixel information regardless of its scale. Considered in another way, a pixel has no inherent size or unit (a pixel is actually

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