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71-655: The JPEG 2000 project was motivated by Ricoh's submission in 1995 of the CREW ( C ompression with R eversible E mbedded W avelets) algorithm to the standardization effort of JPEG-LS . Ultimately the LOCO-I algorithm was selected as the basis for JPEG-LS , but many of the features of CREW ended up in the JPEG 2000 standard. JPEG 2000 codestreams are regions of interest that offer several mechanisms to support spatial random access or region of interest access at varying degrees of granularity. It

142-517: A 16Base file contains a Base/16, Base/4, Base and 4Base image as well as the 16Base components. The sixth component, 64Base, is stored in separate files on the Photo CD as part of the IMAGE PAC Extension (IPE). This only exists on Photo CD Pro Master discs. PCD images use a gamma transformed PhotoYCC encoding. Under this scheme, in order to encode scanned images into Photo CD file, the first step

213-459: A Service (SaaS) document management applications such as DocumentMall, RicohDocs, GlobalScan, Print&Share, MakeLeaps and also offers Projectors. In the late 1990s through early 2000s, the company grew to become the largest copier manufacturer in the world. During this time, Ricoh acquired Savin , Gestetner , Lanier, Rex-Rotary, Monroe , Nashuatec , IKON and most recently IBM Printing Systems Division / Infoprint Solutions Company. Although

284-412: A codec will try to build layers in such a way that the image quality will increase monotonically with each layer, and the image distortion will shrink from layer to layer. Thus, layers define the progression by image quality within the codestream. The problem is now to find the optimal packet length for all code blocks which minimizes the overall distortion in a way that the generated target bitrate equals

355-501: A consequence of this flexibility, JPEG 2000 requires codecs that are complex and computationally demanding. Another difference, in comparison with JPEG, is in terms of visual artifacts : JPEG 2000 only produces ringing artifacts , manifested as blur and rings near edges in the image, while JPEG produces both ringing artifacts and 'blocking' artifacts, due to its 8×8 blocks . JPEG 2000 has been published as an ISO standard, ISO/IEC 15444. The cost of obtaining all documents for

426-434: A factor of 2 (4:2:0) for all other resolutions. Secondly an additional reduction in size is achieved by decomposing the highest-resolution image data, and storing the 4Base, 16Base and 64Base components as residuals (differences from pixels at the previous level of resolution). Thirdly and finally, the Photo CD system employs a form of quantization and Huffman coding to further compress this residual data. This Huffman encoding

497-559: A fair level of acceptance among professional photographers due to the low cost of the high quality film scans. Prior to Photo CD, professionals who wished to digitize their film images were forced to pay much higher fees to obtain drum scans of their film negatives and transparencies . Both JPEG and JPEG 2000 support PhotoYCC colorspace as described below that is used in Photo CD files. The Kodak Pro Photo CD Master Disc contains 25 images with maximum resolution of 6144 x 4096 pixels (six resolutions per file, Base/16 to 64 Base). This type

568-437: A lower peak signal-to-noise ratio . Using many tiles can create a blocking effect similar to the older JPEG  1992 standard. These tiles are then wavelet-transformed to an arbitrary depth, in contrast to JPEG 1992 which uses an 8×8 block-size discrete cosine transform . JPEG 2000 uses two different wavelet transforms: The wavelet transforms are implemented by the lifting scheme or by convolution . After

639-465: A number of other open source implementations of Photo CD decoders such as ImageMagick. In 2009, pcdtojpeg was created under the GPL open source licence. Also acknowledged by the author to be based on Hadmut Danisch's reverse engineering work, pcdtojpeg allows Photo CD metadata to be decoded, is color managed, and can decode all known variants of Photo CD files. Currently hpcdtoppm and pcdtojpeg together form

710-494: A precinct into one indivisible unit. Packets are the key to quality scalability (i.e., packets containing less significant bits can be discarded to achieve lower bit rates and higher distortion). Packets from all sub-bands are then collected in so-called layers . The way the packets are built up from the code-block coding passes, and thus which packets a layer will contain, is not defined by the JPEG ;2000 standard, but in general

781-481: A result, by the time that the Photo CD format fell into disuse, five different color spaces were in common use in Photo CD images (PCD 4050 is a Kodak scanner model number): Thus, while the use of the generic Photo CD color space will provide color reproduction that is acceptable for many purposes e.g., Web viewing of thumbnail images, in order to achieve fully accurate color reproduction, e.g., for photographic purposes, any Photo CD display or conversion software must use

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852-435: A resulting fall in quality. As a result of Photo CD's loss of market share and substantial corporate losses, partially attributed by Kodak Management to its scanning business, Kodak abandoned the format over the period 2001-2004. By 2004, Kodak 4050 Photo CD scanners were being offered for free to anyone that would pay for their removal by more than one processing lab. This abandonment generated considerable controversy both at

923-820: A reversible integer wavelet transform in JPEG 2000. Like JPEG 1992, JPEG 2000 is robust to bit errors introduced by noisy communication channels, due to the coding of data in relatively small independent blocks. The JP2 and JPX file formats allow for handling of color-space information, metadata, and for interactivity in networked applications as developed in the JPEG Part 9 JPIP protocol. JPEG 2000 supports bit depths of 1 to 38 bits per component. Supported color spaces include monochrome, 3 types of YCbCr, sRGB, PhotoYCC , CMY(K), YCCK and CIELab. It also later added support for CIEJab ( CIECAM02 ), e-sRGB, ROMM, YPbPr and others. Full support for transparency and alpha planes. The JPEG 2000 image coding system (ISO/IEC 15444) consists of

994-457: A smaller part of the whole file has been received, the viewer can see a lower quality version of the final picture. The quality then improves progressively through downloading more data bits from the source. Like the Lossless JPEG standard, the JPEG 2000 standard provides both lossless and lossy compression in a single compression architecture. Lossless compression is provided by the use of

1065-399: A special application of the method of Lagrange multiplier which is used for optimization problems under constraints. The Lagrange multiplier , typically denoted by λ, turns out to be the critical slope, the constraint is the demanded target bitrate, and the value to optimize is the overall distortion. Packets can be reordered almost arbitrarily in the JPEG 2000 bit-stream; this gives

1136-507: A suitable software ( LaserSoft Imaging's SilverFast DC or HDR for example). The system failed to gain mass usage among consumers partly due to its proprietary nature, the rapidly decreasing scanner prices, and the lack of CD-ROM drives in most home personal computers of the day. Furthermore, Photo CD relied on CRT -based TV sets for home use. However, these were designed for moving pictures. Their typical flicker became an issue when watching still photographs. The Photo CD system gained

1207-474: Is applied to the chroma channels. Kodak based the PhotoYCC scheme on some existing video standards, notably on aspects of CCIR Recommendation 601 used with PAL and NTSC digital television systems, and also on CCIR Recommendation 709 (now ITU-R Recommendation BT.709) used for HDTV. The PhotoYCC definition is defined in a manner that is not constrained by the limitations of the actual video display. In practice

1278-441: Is appropriate for 120 film, 4x5, but also for small picture film, if highest resolution is required. Separate from the Photo CD format is Kodak 's proprietary "Portfolio CD" format, which combines Red Book CD audio and Beige Book PCD with interactive menus and hotspots on PCD images. Some standalone Philips Photo/Audio CD players could play Portfolio CDs, and Windows player application was freely available. The Kodak Portfolio CD

1349-415: Is called JPX, and should use the file extension .jpf , although .jpx is also used. There is no standardized extension for codestream data because codestream data is not to be considered to be stored in files in the first place, though when done for testing purposes, the extension .jpc , .j2k or .j2c is commonly used. For traditional JPEG, additional metadata , e.g. lighting and exposure conditions,

1420-508: Is generally not supported in web browsers for web pages as of 2024, and hence is not generally used on the World Wide Web . Nevertheless, for those with PDF support, web browsers generally support JPEG 2000 in PDFs. While there is a modest increase in compression performance of JPEG 2000 compared to JPEG, the main advantage offered by JPEG 2000 is the significant flexibility of

1491-723: Is kept in an application marker in the Exif format specified by the JEITA. JPEG 2000 chooses a different route, encoding the same metadata in XML form. The reference between the Exif tags and the XML elements is standardized by the ISO TC42 committee in the standard 12234-1.4. Extensible Metadata Platform can also be embedded in JPEG 2000. ISO 15444 is covered by patents and the specification lists 17 patent holders, but

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1562-413: Is not defined in any particular Rainbow Book. The Photo CD system was announced by Kodak in 1990. Photo CD targeted a full range of photographic needs, ranging from consumer level point-and-shoot cameras to high-end professionals using large format 4x5 sheet film. The first Photo CD products, including scanners for processing labs and Photo CD players for consumers, became available in 1992. The project

1633-424: Is not provided, Kodak expressly allows the use of R, G, B < 0, allowing out-of-gamut (for Rec. 709) colors to be expressed. The effect is similar to xvYCC , which came much later. Photo CD images use three forms of compression in order to reduce image storage requirements. Firstly, chroma subsampling reduces the size of the images by approximately 50%. This subsampling is by a factor of 4 for 4Base images, and

1704-421: Is performed (it is used in lossless compression). The result of the previous process is a collection of sub-bands which represent several approximation scales. A sub-band is a set of coefficients — real numbers which represent aspects of the image associated with a certain frequency range as well as a spatial area of the image. The quantized sub-bands are split further into precincts , rectangular regions in

1775-457: Is performed on an image-row-by-image-row basis. The Huffman tables are encoded into the Photo CD image itself, and have different lengths depending on the compression class. These Huffman classes are: For example, to recompose an image of 1024 lines by 1536 pixels, the 512-line by 768-pixel luma Base image (which is neither "residual" or Huffman compressed) is interpolated to a 1024-line by 1536-pixel image. A 1024-line by 1536-pixel 4Base residual

1846-425: Is possible through appropriate tile or partition selection. All these operations do not require any re-encoding but only byte-wise copy operations. Compared to the previous JPEG standard, JPEG 2000 delivers a typical compression gain in the range of 20%, depending on the image characteristics. Higher-resolution images tend to benefit more, where JPEG 2000's spatial-redundancy prediction can contribute more to

1917-461: Is possible to store different parts of the same picture using different quality. JPEG 2000 is a compression standard based on a discrete wavelet transform (DWT). The standard could be adapted for motion imaging video compression with the Motion JPEG ;2000 extension. JPEG 2000 technology was selected as the video coding standard for digital cinema in 2004. However, JPEG 2000

1988-484: Is the cause of the well documented "Blown Highlights" problem when converting Photo CD images to more modern formats. All modern photo formats enforce hard clipping at 100% (video formats in YUV still have headroom that is present on high level TVs), resulting in highlight clipping in converted images unless some form of Photo CD specific luminance and chrominance mapping is performed. In addition, although "toeroom" (Y < 0)

2059-471: Is then decompressed from its Huffman-encoded form, and its elements are added to each corresponding pixel. The resulting image contains detail for the full 1024-line by 1536-pixel sampled image. To recompose an image to a resolution of 2048 lines by 3072 pixels, the process is essentially repeated, using both the 4Base and 16Base residual. A similar operation is subsequently used to recompose the 4096 line by 6144 pixel resolution. In each step, an identical process

2130-562: Is to preshape the RGB data via a non-linear transform (the Rec. 709 OETF flipped to become an odd function , same as the later xvYCC ): In Kodak documentation, α = 1.099, β = 0.018. However, the full standard values (1.099296826809442, 0.018053968510807) provide mathematical continuity. As a result of this function, colors that are outside of the gamut defined by the CCIR 709 primaries are encoded by

2201-684: The public under the Ricoh brand includes: Photo CD Photo CD is a system designed by Kodak for digitizing and saving photos onto a CD. Launched in 1991, the discs were designed to hold nearly 100 high quality images, scanned prints and slides using special proprietary encoding. Photo CDs are defined in the Beige Book and conform to the CD-ROM XA and CD-i Bridge specifications as well. They were intended to play on CD-i players, Photo CD players ( Apple's PowerCD for example), and any computer with

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2272-584: The Americas, Europe, China, and the Asia-Pacific. Ricoh has 272 subsidiaries (72 national and 200 overseas) which specialize in technology- and customer-research groups around the world. For example, Ricoh Innovations, a research subsidiary of Ricoh Company, operates in Silicon Valley , California , focusing on technology, cloud, mobile solutions, and customer research. A partial list of products marketed to

2343-489: The Base/16 through 16Base resolutions are stored in a single file called an Image Pac. The Base, Base/4, and Base/16 images are stored uncompressed in order to allow easy extraction for display. 4Base and 16Base images are stored compressed, and as deltas (incremental images) from the resolution below them. Note all resolutions up the maximum resolution in a file (actually an Image Pac) are all present simultaneously. So, for example,

2414-473: The EBCOT, and no bit planes can be dropped. The bits selected by these coding passes then get encoded by a context-driven binary arithmetic coder , namely the binary MQ-coder (as also employed by JBIG2 ). The context of a coefficient is formed by the state of its eight neighbors in the code block. The result is a bit-stream that is split into packets where a packet groups selected passes of all code blocks from

2485-460: The ITU-T and ISO patent declaration databases (available at https://www.iso.org/iso-standards-and-patents.html ) ISO and IEC take no position concerning the evidence, validity and scope of these patent rights. Ricoh The Ricoh Company, Ltd. ( / ˈ r iː k oʊ / ) ( 株式会社リコー , Kabushiki-gaisha Rikō ) is a Japanese multinational imaging and electronics company . It was founded by

2556-484: The JPEG committee stated in "Annex L: Patent statement": The International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC) draw attention to the fact that it is claimed that compliance with this Recommendation | International Standard may involve the use of patents. The complete list of intellectual property rights statements can be obtained from

2627-715: The Monroe brand was discontinued, products continue to be marketed worldwide under the remaining brand names. In 2006, Ricoh acquired the European operations of Danka for $ 210 million. These operations continue as a stand-alone business unit, under the Infotec brand. The Ricoh Group has sales and support, production, and research and development operations in nearly 180 countries. It has its world headquarters in Tokyo, Japan and regional headquarters in Japan,

2698-522: The Photo CD format was designed in the early 1990s, a design goal was to allow low cost playback-to-TV devices. At that time the available technology precluded 2-dimensional compression schemes such as JPEG, but by the late 1990s, advances in microprocessor technology had moved JPEG/PNG compression to well within the range of even very low cost consumer electronics. In the professional and advanced amateur segments, Photo CD had been eclipsed by low cost desktop scanners such as those from Nikon and Minolta in

2769-590: The algorithm of JPEG 2000. According to the Royal Library of the Netherlands , "the current JP2 format specification leaves room for multiple interpretations when it comes to the support of ICC profiles, and the handling of grid resolution information". Initially images have to be transformed from the RGB color space to another color space, leading to three components that are handled separately. There are two possible choices: If R, G, and B are normalized to

2840-462: The codestream. The codestream obtained after compression of an image with JPEG 2000 is scalable in nature, meaning that it can be decoded in a number of ways; for instance, by truncating the codestream at any point, one may obtain a representation of the image at a lower resolution, or signal-to-noise ratio – see scalable compression . By ordering the codestream in various ways, applications can achieve significant performance increases. However, as

2911-446: The color space of Photo CD images varies significantly from Rec. 709. Firstly, the Photo CD encoding scheme allows greater than 100% values for color components, thus allowing Photo CD images to display colors outside of the nominal Rec. 709 gamut. In addition, in order to achieve accurate color reproduction, especially when scanning reversal film, Kodak found it necessary to provide ICC color profiles specific to film type and scanner. As

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2982-490: The compression process. In very low-bitrate applications, studies have shown JPEG 2000 to be outperformed by the intra-frame coding mode of H.264. JPEG 2000 is much more complicated in terms of computational complexity in comparison with JPEG standard. Tiling, color component transform, discrete wavelet transform, and quantization could be done pretty fast, though entropy codec is time-consuming and quite complicated. EBCOT context modelling and arithmetic MQ-coder take most of

3053-401: The consumer segment, the Photo CD format's relatively inefficient compression scheme meant that Photo CD files were significantly larger than JPEG files of similar quality, and thus less convenient for transmission across the internet, etc. For example, a 16Base Photo CD image of 5.5 Mb can be encoded as a JPEG image of 2.1 Mb at 80% quality, visually indistinguishable from the original. When

3124-693: The contributing companies and organizations agreed that licenses for its first part—the core coding system—can be obtained free of charge from all contributors. But this is not a formal guarantee. License and royalties may be required to use some extensions. The JPEG committee has stated: It has always been a strong goal of the JPEG committee that its standards should be implementable in their baseline form without payment of royalty and license fees... The up and coming JPEG 2000 standard has been prepared along these lines, and agreement reached with over 20 large organizations holding many patents in this area to allow use of their intellectual property in connection with

3195-610: The core of information available in the public domain on the technical details of the Photo CD format. Photo CD images are stored as a hierarchy of components ranging from Base/16 to 64Base which relate to the varying image resolutions that can be reconstructed. The Base image, which has a luma resolution of 512 lines by 768 pixels, is typically used for the TV systems. The higher-resolution images are usually used for photographic imaging. The Base and lower resolution images are usually used for file indexes and thumbnails. The components used to create

3266-403: The demanded bit rate. While the standard does not define a procedure as to how to perform this form of rate–distortion optimization , the general outline is given in one of its many appendices: For each bit encoded by the EBCOT coder, the improvement in image quality, defined as mean square error, gets measured; this can be implemented by an easy table-lookup algorithm. Furthermore, the length of

3337-495: The design to handle a very large range of effective bit rates is one of the strengths of JPEG 2000. For example, to reduce the number of bits for a picture below a certain amount, the advisable thing to do with the first JPEG standard is to reduce the resolution of the input image before encoding it. That is unnecessary when using JPEG 2000, because JPEG 2000 already does this automatically through its multi-resolution decomposition structure. The following sections describe

3408-434: The dynamic range of scans was lower than for desktop scanners. Tests at the time indicated that the dmax rating (a measure of maximum density obtainable) of Photo CD was 2.8-3.0, while commonly available desktop scanners were reaching 4.2, a substantial difference. As a result of this, and Photo CD's problems with color rendering, by 2004 the professional segment of the user community had generally turned against Photo CD. In

3479-401: The encoder as well as image servers a high degree of freedom. Already encoded images can be sent over networks with arbitrary bit rates by using a layer-progressive encoding order. On the other hand, color components can be moved back in the bit-stream; lower resolutions (corresponding to low-frequency sub-bands) could be sent first for image previewing. Finally, spatial browsing of large images

3550-468: The finest wavelet scale. This step is called multiple component transformation in the JPEG 2000 language since its usage is not restricted to the RGB color model . After color transformation, the image is split into so-called tiles , rectangular regions of the image that are transformed and encoded separately. Tiles can be any size, and it is also possible to consider the whole image as one single tile. Once

3621-534: The following equations: Kodak claims that "the scale factors and offsets for the C1 and C2 channels result from the distribution of real world colors". Given the 8-bit integer range for each of the 3 components, 0 ≤ Y ≤ 1.402, -1.40036 ≤ B' - Y' ≤ 0.888689, -1.01003 ≤ G' - Y' ≤ 0.86995. An oddity of this encoding scheme is that it allows Photo CD images to represent colors which are above 100% (up to 140.2%), " whiter than white ". At

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3692-469: The following parts: The aim of JPEG 2000 is not only improving compression performance over JPEG but also adding (or improving) features such as scalability and editability. JPEG 2000's improvement in compression performance relative to the original JPEG standard is actually rather modest and should not ordinarily be the primary consideration for evaluating the design. Very low and very high compression rates are supported in JPEG 2000. The ability of

3763-493: The image samples, JPEG-1 includes additional meta-information such as the resolution of the image or the color space that has been used to encode the image. JPEG 2000 images should—if stored as files—be boxed in the JPEG 2000 file format, where they get the .jp2 extension. The part-2 extension to JPEG 2000 (ISO/IEC 15444-2) enriches the file format by including mechanisms for animation or composition of several codestreams into one single image. This extended file format

3834-520: The mid range, and by drum scanners at the very high end. While the pixel resolution of Photo CD was still comparable or better than the alternatives, Photo CD suffered from a number of other disadvantages. Firstly, the Photo CD color space, designed for TV display, is smaller than what can be achieved by even a low cost desktop scanner. Secondly, the color rendition of Photo CD images changed over time and with different scanner versions; 4050 scanners had different color rendition to earlier versions. Thirdly,

3905-741: The most significant bits and progressing to less significant bits by a process called the EBCOT scheme. EBCOT here stands for Embedded Block Coding with Optimal Truncation . In this encoding process, each bit plane of the code block gets encoded in three so-called coding passes , first encoding bits (and signs) of insignificant coefficients with significant neighbors (i.e., with 1-bits in higher bit planes), then refinement bits of significant coefficients and finally coefficients without significant neighbors. The three passes are called Significance Propagation , Magnitude Refinement and Cleanup pass, respectively. In lossless mode all bit planes have to be encoded by

3976-486: The negative values. Linear RGB values are from -0.20 to 2.00, while nonlinear RGB' are from -0.43357 to 1.402278. Reference white (perfect, non-fluorescent, white-reflecting diffuser in the original scene) is 1.0, just like in BT.709. The preshaped RGB values are then converted to a luminance and two chrominance components via a CCIR 601-1-like matrix: Finally the luminance and chrominance components are scaled to 8-bit values by

4047-518: The now-defunct commercial division of the Institute of Physical and Chemical Research (Riken) known as the Riken Concern , on 6 February 1936 as Riken Sensitized Paper ( 理研感光紙 , Riken Kankōshi ) . Ricoh's headquarters are located in Ōta, Tokyo . Ricoh produces electronic products, primarily cameras and office equipment such as printers , photocopiers , fax machines, offers Software as

4118-444: The resulting codestream gets measured. This forms for each code block a graph in the rate–distortion plane, giving image quality over bitstream length. The optimal selection for the truncation points, thus for the packet-build-up points is then given by defining critical slopes of these curves, and picking all those coding passes whose curve in the rate–distortion graph is steeper than the given critical slope. This method can be seen as

4189-417: The retail segment, while Photo CD was initially relatively popular with consumers, it was largely an economic failure for processing labs. At the time of its introduction, Kodak claimed that processing costs to labs would be close to $ 1 per image, which would allow the lab profitably sell at the $ 3 per image mark. However this promise was never realized, often resulting in the scanning process being rushed, with

4260-425: The same precision, then numeric precision of C B and C R is one bit greater than the precision of the original components. This increase in precision is necessary to ensure reversibility. The chrominance components can be, but do not necessarily have to be, downscaled in resolution; in fact, since the wavelet transformation already separates images into scales, downsampling is more effectively handled by dropping

4331-399: The size is chosen, all the tiles will have the same size (except optionally those on the right and bottom borders). Dividing the image into tiles is advantageous in that the decoder will need less memory to decode the image and it can opt to decode only selected tiles to achieve a partial decoding of the image. The disadvantage of this approach is that the quality of the picture decreases due to

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4402-656: The standard has been estimated at 2,718   CHF ( US$ 2,720 as of 2015). Notable markets and applications intended to be served by the standard include: JPEG 2000 decomposes the image into a multiple resolution representation in the course of its compression process. This pyramid representation can be put to use for other image presentation purposes beyond compression. These features are more commonly known as progressive decoding and signal-to-noise ratio (SNR) scalability . JPEG 2000 provides efficient codestream organizations which are progressive by pixel accuracy and by image resolution (or by image size). This way, after

4473-444: The standard without payment of license fees or royalties. However, the JPEG committee acknowledged in 2004 that undeclared submarine patents may present a hazard: It is of course still possible that other organizations or individuals may claim intellectual property rights that affect implementation of the standard, and any implementers are urged to carry out their own searches and investigations in this area. In ISO/IEC 15444-1:2016,

4544-402: The then relatively low cost of $ 3 per image and convenience, made Photo CD the digital imaging solution of choice for many photographers in the mid to late 1990s. By 2000, over 140 Photo CD processing labs in the U.S. were active, with many more outside the U.S. However, by the late 1990s, Photo CD was being eclipsed by alternate formats, mainly based on the industry standard JPEG format. In

4615-458: The time and subsequently as the Photo CD format's technical specifications have never been released by Kodak. Photo CD remains an often quoted example of an “orphan format” and of the dangers of proprietary image formats within photographic circles. Despite Kodak not releasing the specifications for the Photo CD format, it has been reverse engineered, thus allowing images to be converted to more modern formats. The original reverse engineering work

4686-422: The time of JPEG 2000 codec. On CPU the main idea of getting fast JPEG 2000 encoding and decoding is closely connected with AVX/SSE and multithreading to process each tile in a separate thread. The fastest JPEG 2000 solutions utilize both CPU and GPU power to get high performance benchmarks. Similar to JPEG-1, JPEG 2000 defines both a file format and a codestream. Whereas JPEG 2000 entirely describes

4757-404: The time of Photo CD's introduction, this allowed the display of images on the analog televisions of the day to show brighter, more vivid colors than would otherwise be the case. This was acceptable as the analog televisions of the day were designed to be driven beyond their 100% level without abruptly clipping. However, this aspect of Photo CD encoding is not compatible with modern image formats, and

4828-418: The wavelet domain. They are typically sized so that they provide an efficient way to access only part of the (reconstructed) image, though this is not a requirement. Precincts are split further into code blocks . Code blocks are in a single sub-band and have equal sizes—except those located at the edges of the image. The encoder has to encode the bits of all quantized coefficients of a code block, starting with

4899-432: The wavelet transform, the coefficients are scalar- quantized to reduce the number of bits to represent them, at the expense of quality. The output is a set of integer numbers which have to be encoded bit-by-bit. The parameter that can be changed to set the final quality is the quantization step: the greater the step, the greater is the compression and the loss of quality. With a quantization step that equals 1, no quantization

4970-499: Was expected to be a $ 600 million business by 1997 with $ 100 million in operational earnings. Kodak entered into a number of partnerships in order to grow the usage of Photo CD. This included, for example, an arrangement with L.L. Bean in 1992 by which the catalog would be distributed in Photo CD format, and an arrangement with Silicon Graphics in 1993 to make all Silicon Graphics image-processing workstations capable of accepting Kodak Photo CD optical disks. These measures, together with

5041-606: Was performed by Hadmut Danisch of the University of Karlsruhe , who deciphered the format by studying hex dumps of Photo CD files, and subsequently wrote hpcdtoppm, which converts Photo CD Images to PPM format, in the early 1990s. During the early 1990s, hpcdtoppm was extensively distributed as part of various Linux distributions, but has since been almost entirely abandoned due to concerns about hpcdtoppm's restrictive license conditions and lack of color management. However, Hadmut Danisch's reverse engineering work has been used to create

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