WO2014132096A1 - Conversion de couleur de bloc - Google Patents

Conversion de couleur de bloc Download PDF

Info

Publication number
WO2014132096A1
WO2014132096A1 PCT/IB2013/000602 IB2013000602W WO2014132096A1 WO 2014132096 A1 WO2014132096 A1 WO 2014132096A1 IB 2013000602 W IB2013000602 W IB 2013000602W WO 2014132096 A1 WO2014132096 A1 WO 2014132096A1
Authority
WO
WIPO (PCT)
Prior art keywords
color
color space
block
rgb
values
Prior art date
Application number
PCT/IB2013/000602
Other languages
English (en)
Inventor
Alexandre Delattre
Janos BOUDET
Original Assignee
Nintendo European Research And Development
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nintendo European Research And Development filed Critical Nintendo European Research And Development
Priority to PCT/IB2013/000602 priority Critical patent/WO2014132096A1/fr
Priority to EP13723949.7A priority patent/EP2962449A1/fr
Publication of WO2014132096A1 publication Critical patent/WO2014132096A1/fr

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/46—Colour picture communication systems
    • H04N1/56—Processing of colour picture signals
    • H04N1/60—Colour correction or control
    • H04N1/6058—Reduction of colour to a range of reproducible colours, e.g. to ink- reproducible colour gamut
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/46—Colour picture communication systems
    • H04N1/56—Processing of colour picture signals
    • H04N1/60—Colour correction or control
    • H04N1/6002—Corrections within particular colour systems
    • H04N1/6005—Corrections within particular colour systems with luminance or chrominance signals, e.g. LC1C2, HSL or YUV
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/46—Colour picture communication systems
    • H04N1/64—Systems for the transmission or the storage of the colour picture signal; Details therefor, e.g. coding or decoding means therefor

Definitions

  • This technology relates to digital image processing, and more particularly to image block color conversion systems and methods. Still more particularly, the technology herein relates to improving RGB to YUV or other color standard conversion with chroma downsample. In more detail, the technology herein provides improved RGB to YUV conversion with chroma downsampling that happens at the first stage of many (most) image and video compression techniques. It has applicability in computer graphics, video processing and image processing among others. BACKGROUND AND SUMMARY
  • the RGB color model is widely used for electronic color display and image representation technology in computers, digital video, smart phones, high definition television and many other applications.
  • the intensity of each color component is represented by a digital number or value.
  • the commonly-used sRGB color standard for consumer electronics represents each color component with 8 digital bits.
  • the gamut of chromaticities that can be represented in sRGB is the color space defined by the Red/Green/Blue primary colors. For non-negative values, this sRGB representation is unable to represent colors outside of this color space, which is well inside the range of colors visible to a human.
  • RGB format used by many hardware manufacturers
  • YUV pixel formats used by the JPEG and MPEG compression methods
  • V ((112 * R - 94 * G - 18 * B + 128) » 8) + 128
  • clip() denotes clipping a value to the range of 0 to 255.
  • converting from RGB to YUV involves converting one RGB image into three separate images: a Y image, a U (difference) image and a V (difference) image.
  • the Y image in many contexts is the same size and resolution as the original color image but contains only luma (brightness) information and no color information. The color information is contained in the additional U and V images. See Figure 1.
  • the RGB color information may be downsampled to provide a YUV4:2:0 image or any other form of downsampling.
  • YUV420 is a planar format, meaning that the Y, U, and V values are grouped together instead of being interspersed.
  • the U and V are generally both downsampled, whereas in many applications the Y component will not be downsampled.
  • the image becomes more compressible in many practical implementations - and the higher resolution Y luma value continues to provide higher resolution image detail whereas the downsampled U, V values supply color information with less resolution than provided by the original RGB representation.
  • such downsampling or sub-sampling is a lossy process that decreases the color resolution of the U and V color information and thus the amount of information that needs to be transmitted and/or stored.
  • This loss of color information allows higher compression ratios to be achieved while usually maintaining acceptable image color quality.
  • YUV4:2:0 a common representation used in MPEG
  • the U and V color values are resampled to provide only 1 ⁇ 4 the number of color values in each of U and V as compared to the Y luma values. See prior art Fig. 2.
  • the resulting YUV values are then upsampled after storage or transmission to reconstruct RGB values for display or other processing.
  • the lossy UV compression described above gives a 2x compression ratio (in this particular non-limiting example) that will be a starting point for any subsequent compression/decompression process to achieve further compactness for data storage and/or transmission.
  • the YUV420 color space has lower resolution than the original RGB 2x2 color space. This means some valid colors in the original RGB 2x2 color space cannot be represented in the lower-resolution YUV420 color space. If the YUV240 representation of a particular 2x2 color block is a close approximation of the scRGB representation, a human who perceives the result will not notice the difference. However, there can be some cases where the difference is quite noticeable. For example, if the original RGB 2x2 color block was being used to encode contrasting colors (e.g., bright red on a black background), then the loss of color resolution due to the conversion may generate a very noticeable artifact of the color conversion process. This is undesirable.
  • contrasting colors e.g., bright red on a black background
  • the example non-limiting technology herein exploits the characteristic that color block conversion can produce YUV values that fall outside of the RGB range when decoded in order to provide a more optimized and higher fidelity overall block color conversion.
  • Such improved conversion can be applied selectively, or it can be applied to all blocks in the original image. Even if applied to all blocks, the non-limiting example improved conversion will not degrade results as compared to conventional conversion techniques, and will provide noticeable improvements especially for certain image blocks such as for example high contrast situations (e.g., red on black).
  • the example non-limiting implementation works on block+color spaces and helps wherever a system will perform a colorspace conversion followed by or combined with an upsample.
  • the example non-limiting technique creates YUV420 block values that do not lie in the traditional output range of standard downsamplers and exploits the fact that standard decoders project out of range reconstructed RGB values back into their normal range. While some out of range values may already get produced by standard encoders (and this is good, because existing decoders are therefore already capable of handling it), the example non-limiting technology herein produces values that are even more systematically out of range to improve and optimize image quality. More Detailed Example
  • converting a w x h RGB image with downsampling into YUV 420 thus results in three images: aw x h Y image and two ⁇ ⁇ images, that can be independent in memory, or interlaced.
  • Figure 1 thus shows a w x h RGB image on the left-hand side being converted into a w x h Y image on the right-hand side plus two additional 1 ⁇ 4-sized U & V color difference images.
  • a full range of colors (within the limitation of the size of the YUV 420 color space) can be obtained when these three apparently-monochromatic images are recombined in a decoding process.
  • the non-limiting example color conversion task global across the image is broken up into smaller independent (local) tasks based on blocks or subsets of the color image.
  • a local task considers a 2 x 2 RGB block of the original image, and converts it into six values (four Y values, one U value and one V value):
  • the canonical way to convert a four pixel (2 x 2 RGB values £ RGB ) RGB block into a YUV output with downsampled UV is to apply the quasi affine transform (note that we also discuss below the case of bilinear upsampling).
  • matrix M 4 has many zeroes and symmetries, so the actual full matrix multiplication is not carried out in efficient real world implementations. Also note that this matrix is the orthogonal projection matrix that projects RGB 4 onto M 4 -R 4 -YUV 42 o as vector spaces using the orthogonality defined by the following YUV dot product applied to RGB vectors:
  • the example non-limiting color conversion process described above does not operate on vector spaces, but rather on (bounded) subregions of vector spaces.
  • YUV420 (as a vector space) is a sub vector space of RGB4 (as a vector space)
  • YUV420 (as a bounded block color space) is not entirely contained in RGB4 (as a bounded block color space).
  • orthogonal projection is not always the optimal way to perform the color conversion processes.
  • a quasi affine transform (QAT) for RGB ⁇ YUV color space conversion may use matrix M in the form:
  • quadsi affine is used instead of affine because after the transform matrix is applied, the output color vector is clamped, using the saturate (sat) operator, to a certain range (usually [0..1.0] or [0..255]) so as to avoid overflows in processors used to perform the computation.
  • the inverse YUV RGB color space conversion may be in the form
  • the example non-limiting technology herein uses a less complex, more practical method that aims at achieving most of the gain of the full method, but having a cost closer to the standard method.
  • our exemplary illustrative non-limiting example implementation takes advantage of the fact that while generally speaking in a downsampled situation, target YUV color space has less resolution than the original RGB color space representing the original image, the YUV color space is capable of representing certain colors that are not representable in the original RGB color space. Meanwhile, conventional video decoding hardware and software will project those certain colors back into the RGB color space.
  • one example non-limiting implementation assumes that we have a known decode process called D, and we want to find the encode process E+ that improves upon E, the standard encode process, such that, for each input pixel block x,
  • One non-limiting example implementation provides an individual fast Y optimization method that yields the best possible results if we only allow our to have the Y's modified compared to the standard method. It is safe, because it always yields results at least as good as the standard process.
  • the UV can also be optimized. If we choose to optimize the UV as compared to the standard method, we can subsequently use the aforementioned Y optimization to further improve the results. This in turns provides two example non-limiting possible venues:
  • one non-limiting approach optimizes the UV based on a heuristic.
  • One proposed non-limiting heuristic is based on the observation that saturated pixels are able to recover quality by optimizing their Ys, whereas non saturated pixels cannot. Therefore, it is sensible to shift the common UV towards the unsaturated pixels, since the saturated pixels can cover their losses by changing their Ys.
  • the Y range is bounded (so it cannot compensate too large distortions), and single dimensional (so it cannot fix both U and V at the same time), so it is to mildly shift the UV towards the unsaturated pixel components instead of trying to shoot straight for the optimum point.
  • this non- limiting example heuristic relies on the fact that the saturated pixel set remains constant when we move the UV value around. This is only true in a small neighborhood around the initial (standard converted) UV, and that's why it's better to underestimate the UV shift, so as to not introduce undesirable errors.
  • Figure 1 shows an example conversion from RGB to YUV color space
  • Figure 2 shows example conventional sRGB to YUV420 downsampling
  • Figure 3 shows an example non-limiting computer processing architecture for compressing a color image for transmission and/or storage
  • FIGS 3A-3C show example non-limiting simplified color conversions for purposes of illustration
  • Figures 3D-3E are example non-limiting illustrations of conversion of color blocks between an RGB color space and a YUV color space;
  • Figure 4 shows an example more detailed processing flowchart for compressing an RGB image
  • Figure 5 shows an example non-limiting computer processing architecture for decompressing and using a color image.
  • Figure 3 shows an example non-limiting computer processing architecture for encoding a color image 10 into a file 50 for storage in non-transitory storage 30 and/or into a stream for transmission over a network 40 or other transmission path.
  • Color image 10 can be derived from any source such as a graphics processor, a camera, or any other source capable of providing a color image or sequence of color images.
  • a processor 20 executes program code stored in non-transitory storage 30 to compress the color image while optimizing RGB to YUV conversion.
  • the processor may comprise a state machine, a gate array, digital logic, a digital signal processor, a microcomputer, or any other desired implementation.
  • Figure 4 shows one non-limiting example sequence of separate stages used to compress and encode color image data. Note that some of these steps are aggregated in real implementations, but are separated here so as to give a better view of the logical blocks.
  • an RGB color image 10 (ex. JPEG) is first converted to a YUV444 color image.
  • the YUV420 image is then compressed by a sequence of additional steps (block DCT or "Discrete Cosine Transform", quantization, zigzag RLE or “Run Length Encoding”, and entropy coding) to provide a compressed color image signal for storage and/or transmission.
  • block DCT or "Discrete Cosine Transform", quantization, zigzag RLE or “Run Length Encoding”, and entropy coding
  • the example non-limiting technology herein provides improved conversion techniques between 10 and 200, 300.
  • the processing may be reversed (see Figure 5) to recover the original RGB color image 10 or to convert the decompressed image into some other format for display or other usage.
  • decoding can be performed by a processor comprising a state machine, a gate array, digital logic, a digital signal processor , a microcomputer, or any other desired imp lementation.
  • the decoding side can use conventional hardware and software such as found in many existing prior art devices to decompress and convert the signal from YUV420 to RGB for display or other use.
  • the example non-limiting technology herein produces a compressed output that can be decompressed and otherwise processed by existing prior art devices without any changes whatsoever in the decompression/decoding device.
  • the RGB to YUV block conversion is structured so intentionally produce YUV values that are non-representable in the original RGB color space but which will provide reduced color representation errors when block reconverted back from YUV into target RGB color space using conventional block conversion technology.
  • FIGS 3A-3C show a simplified (2D), but more easily represented version/example non-limiting implementation.
  • the goal is to convert a 2x1 pixel block from RGB to YUV.
  • each pixel has only 2 components (R and G) instead of the typical three components (R,G,B) but in a preferred implementation all three components would be converted and the conversion would be from 3D RGB color space as opposed to 2D RG color space.
  • the output of the conversion is a 3-component value
  • Figures 3A-C have been in connection with A and B representing single pixel values for purposes of simplification, but since the example illustrative non-limiting technology herein operates based on blocks, in Figures 3D (cut version) & 3E (3D version), points P0 .. . PN represent color blocks (e.g., 2x2 pixels).
  • P0 represents the case where the conventional process already provides optimal results.
  • PI shows a conventional block color conversion where the conventional approach yields less than optimal results
  • P2 represents an example non-limiting block color conversion the technology herein provides.
  • the conventional block color conversion transform projects the RGB value into the YUV block color space in a very different way than the transform provided by the example non-limiting optimized implementations described herein.
  • Figure 3D uses notation that matches Figs. A, B and C.
  • the RGB4 gamut of Fig. 3D looks skewed because the YUV norm has been chosen so that color block distances are proportional to the real distances (on paper), and orthogonal projections using that norm are indeed right angles.
  • P0 shows the case where the standard method is indeed optimal
  • PI shows the case where the optimization can provide optimal results
  • P2 shows the case where the optimization improves upon the standard method, but is limited in effect by the fact that the YUV420 boundary is reached, (the ideal optimization is shown next to it).
  • the sat arrows do not necessarily lie within the 3D drawing plane.
  • the dotted lines do however, which is a reason for choosing the YUV norm for this illustrative drawing.
  • rgbi'' iSyi rgb[ + S y .e y
  • rgb"(5 y .) sat(rgb[ + 5 y .e y )
  • ⁇ ⁇ (A*) ⁇ i + 3 ⁇ 43 ⁇ 4 ⁇ - r 9 h i 'yuv
  • An optional and more complex step is choosing the optimal UV value of the yuv 420 block. This step should happen before the Y optimization step, since it assumes that the Y optimization step will be performed afterward. It yields value as the standard transform provided that there is not saturation. Otherwise, its aim is to provide better results. It works by assuming that on a given block, the previous Y optimization method will be applied, and optimizes the block's UV taking this into account. Let (u,v) be the variables we solve for.
  • the Y range can be chosen so as to improve the tradeoff between Y optimization quality and global Y quantization quality.
  • the YUV 42 o ⁇ RGB 4 conversion uses the R 4 matrix (i.e., the UV values are broadcasted identically to the four RGB values), but in some implementations, the uv upscale is done bilinearly.
  • the Y optimization we suggested works perfectly fine, provided that the yuv 42 o ⁇ Tgb[ uses a bilinear upscale too.
  • the UV optimization becomes a global problem not just limited to single 2 x 2 blocks. Notations used above:
  • scalars have the standard typeface, (eg : x)
  • matrices are capital boldface, (eg : M)
  • R stands for red
  • G stands for green.
  • Y stands for luma.
  • U stands for chroma dimension 1.
  • V stands for chroma dimension 2.
  • RGB represents the. [0.. 1] r [0.. 1] g ⁇ [0.. 1]& standard RGB cube.
  • YUV represents the [0.. 1]j ⁇ [0.. 1] M ⁇ [0.. 1] v YUV cube.
  • RGB 4 represents the [0.. 1] 3 '4 ⁇ RGBQ ⁇ RGB ⁇ ⁇ RGB2 x RGB3 12-dimension hypercube of all possible 2 2 RGB pixel blocks.
  • YUV 420 represents the output [0.. 1]6 6-dimension hypercube [O.- lL ⁇ x [0.- 1] ⁇ x 10.. 1 1,, x
  • u-v u T v is used to show a canonical component dot product
  • the example non-limiting technology herein thus provides a process for improving the RGB->YUV BLOCK conversion, for some YUV like colorspace, with some form of downsampling, by exploiting the fact that the decoder will saturate back the values of the decoded rgb values into their allowed ranges.
  • Separately improving the Y's and the UV's is an efficient but non-limiting approach to that problem. If a process is to use both Y and UV optimization, optimizing the UV first is often the right way to go.
  • the example non-limiting technology herein can also perform YUV444 ⁇ YUV420 conversions (among others) e.g.,: the source color space may well be the same as the destination color space, the destination only being downsampled with respect to the source.
  • the decode process could then revert to some other color space, RGB as one non-limiting example.
  • the example non- limiting technology can be used to improve image luma for high contrast image blocks, the non-limiting disclosed technology also provides a method for optimizing the chroma.
  • the combined luma+chroma optimization process non-limiting example disclosed here is only one optimizing method exploiting the fact that decompressors saturate the output RGB values back into their allowed ranges.

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Color Image Communication Systems (AREA)
  • Facsimile Image Signal Circuits (AREA)

Abstract

La conversion améliorée de RVB en YUV avec un processus de sous-échantillonnage de la saturation qui se produit au premier stade de plusieurs (la plupart des) techniques de compression d'image et de vidéo offre une qualité meilleure de façon mesurable que la conversion normale en exploitant le fait que les décompresseurs saturent de nouveau les valeurs de sortie RVB dans leurs plages autorisées pour optimiser ainsi les valeurs de couleurs de résolution inférieure intermédiaire. Des modes de réalisation non limitatifs d'exemple produisent des résultats égaux ou presque égaux à la conversion normale quand cette dernière donne de bons résultats, ont un coût de calcul qui est inférieur à quelques fois le coût de calcul de la conversion normale afin de permettre leur réalisation dans un matériel similaire, atteignent un niveau de qualité proche de celui de l'optimisation à force brute et s'appliquent à toutes les conversions d'espace de couleur quasi affine avec sous-échantillonnage de saturation.
PCT/IB2013/000602 2013-02-26 2013-02-26 Conversion de couleur de bloc WO2014132096A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
PCT/IB2013/000602 WO2014132096A1 (fr) 2013-02-26 2013-02-26 Conversion de couleur de bloc
EP13723949.7A EP2962449A1 (fr) 2013-02-26 2013-02-26 Conversion de couleur de bloc

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/IB2013/000602 WO2014132096A1 (fr) 2013-02-26 2013-02-26 Conversion de couleur de bloc

Publications (1)

Publication Number Publication Date
WO2014132096A1 true WO2014132096A1 (fr) 2014-09-04

Family

ID=48468674

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/IB2013/000602 WO2014132096A1 (fr) 2013-02-26 2013-02-26 Conversion de couleur de bloc

Country Status (2)

Country Link
EP (1) EP2962449A1 (fr)
WO (1) WO2014132096A1 (fr)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108259690A (zh) * 2016-12-28 2018-07-06 乐视汽车（北京）有限公司 图像传输方法和装置
US10560707B2 (en) 2015-03-25 2020-02-11 Dolby Laboratories Corporation Chroma subsampling and gamut reshaping
CN111242863A (zh) * 2020-01-09 2020-06-05 上海酷芯微电子有限公司 基于图像处理器实现的消除镜头横向色差的方法及介质
US10979601B2 (en) 2016-04-04 2021-04-13 Dolby Laboratories Licensing Corporation High precision gamut mapping
US11457239B2 (en) 2017-11-09 2022-09-27 Google Llc Block artefact reduction
CN115396643A (zh) * 2022-08-23 2022-11-25 中船重工（武汉）凌久电子有限责任公司 一种自动路由图像变换方法及系统

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5539540A (en) * 1993-02-12 1996-07-23 Eastman Kodak Company Method and associated apparatus for transforming input color values in an input color space to output color values in an output color space
US20100245383A1 (en) * 2009-03-25 2010-09-30 Mstar Semiconductor, Inc. Circuit for color space conversion and associated method

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5539540A (en) * 1993-02-12 1996-07-23 Eastman Kodak Company Method and associated apparatus for transforming input color values in an input color space to output color values in an output color space
US20100245383A1 (en) * 2009-03-25 2010-09-30 Mstar Semiconductor, Inc. Circuit for color space conversion and associated method

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
JACK: "Video Demystified: A Handbook for the Digital Engineer", 2007, ELSEVIER

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10560707B2 (en) 2015-03-25 2020-02-11 Dolby Laboratories Corporation Chroma subsampling and gamut reshaping
US10979601B2 (en) 2016-04-04 2021-04-13 Dolby Laboratories Licensing Corporation High precision gamut mapping
CN108259690A (zh) * 2016-12-28 2018-07-06 乐视汽车（北京）有限公司 图像传输方法和装置
US11457239B2 (en) 2017-11-09 2022-09-27 Google Llc Block artefact reduction
CN111242863A (zh) * 2020-01-09 2020-06-05 上海酷芯微电子有限公司 基于图像处理器实现的消除镜头横向色差的方法及介质
CN111242863B (zh) * 2020-01-09 2023-05-23 合肥酷芯微电子有限公司 基于图像处理器实现的消除镜头横向色差的方法及介质
CN115396643A (zh) * 2022-08-23 2022-11-25 中船重工（武汉）凌久电子有限责任公司 一种自动路由图像变换方法及系统
CN115396643B (zh) * 2022-08-23 2023-08-29 中船重工（武汉）凌久电子有限责任公司 一种自动路由图像变换方法及系统

Also Published As

Publication number Publication date
EP2962449A1 (fr) 2016-01-06

Similar Documents

Publication Publication Date Title
US11973982B2 (en) Color volume transforms in coding of high dynamic range and wide color gamut sequences
US11025927B2 (en) Pixel pre-processing and encoding
US20240323421A1 (en) High dynamic range adaptation operations at a video decoder
US10242646B2 (en) RGB to YUV format conversion and inverse conversion method and circuit for depth packing and depacking
US10397536B2 (en) Pixel pre-processing and encoding
RU2710291C2 (ru) Способы и устройства для кодирования и декодирования цветного изображения hdr
US20130287308A1 (en) Multi-Compatible Low and High Dynamic Range and High Bit-Depth Texture and Video Encoding System
WO2014132096A1 (fr) Conversion de couleur de bloc
EP0924925A1 (fr) Procédé et appareil pour la conversion réversible de couleurs
US12056864B2 (en) Method and device for obtaining a second image from a first image when the dynamic range of the luminance of the first image is greater than the dynamic range of the luminance of the second image
KR20180044291A (ko) 코딩 및 디코딩 방법과 대응하는 디바이스
EP2222087A1 (fr) Augmentation de la résolution de la profondeur de bits dans un espace de couleur RGB pour réduire la propagation des erreurs en raison de la transformation de l'espace de couleur YUV
EP3298766A1 (fr) Procédé et dispositif de traitement de données d'image couleur représentant des couleurs d'une gamme de couleurs.
US10674182B2 (en) Pixel pre-processing and encoding
US10602109B2 (en) Method and arrangements for HDR encoding
US20040240563A1 (en) Video preprocessor
JP6604109B2 (ja) 色域変換装置、色域変換方法及び色域変換プログラム
JP2017060094A (ja) 映像符号化装置、映像符号化方法、及び映像符号化プログラム、並びに映像復号化装置、映像復号化方法、及び映像復号化プログラム
JPH04324758A (ja) 画像処理方法

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 13723949

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

WWE Wipo information: entry into national phase

Ref document number: 2013723949

Country of ref document: EP