WO1994022108A1 - Rapid thumbnail image reconstruction of dct compressed image data - Google Patents

Rapid thumbnail image reconstruction of dct compressed image data Download PDF

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Publication number
WO1994022108A1
WO1994022108A1 PCT/US1994/002914 US9402914W WO9422108A1 WO 1994022108 A1 WO1994022108 A1 WO 1994022108A1 US 9402914 W US9402914 W US 9402914W WO 9422108 A1 WO9422108 A1 WO 9422108A1
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WO
WIPO (PCT)
Prior art keywords
values
coefficients
quantized
compressed image
dct
Prior art date
Application number
PCT/US1994/002914
Other languages
French (fr)
Inventor
Rafael Retter
Isaac Shenberg
Original Assignee
Zoran Corporation
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.)
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Publication date
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Publication of WO1994022108A1 publication Critical patent/WO1994022108A1/en

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
    • H04N19/169—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding
    • H04N19/18—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding the unit being a set of transform coefficients
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
    • H04N19/102—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or selection affected or controlled by the adaptive coding
    • H04N19/132—Sampling, masking or truncation of coding units, e.g. adaptive resampling, frame skipping, frame interpolation or high-frequency transform coefficient masking
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/30—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using hierarchical techniques, e.g. scalability
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/60—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using transform coding

Definitions

  • This invention relates generally to image compression, and more particularly the invention relates to discrete cosine transform (DCT) -based compression and coding of images and image reconstruction therefrom.
  • DCT discrete cosine transform
  • Image compression is used in reducing large volumes of data in digitized images for convenient and economical storage and for transmission across communication networks having limited band width.
  • Image compression technology is important in digital still video cameras, color scanners, color printers, color fax machines, computers, and multimedia.
  • JPEG Joint Photographic Experts Group
  • DCT-based processes operating on discrete blocks of the image.
  • the DCT coefficients are then quantized based on the measurements of the threshold for visibility.
  • an 8x8 pixel array of DCT coefficients is reorganized into a one- dimensional list using a zigzag sequence which tends to concentrate coefficients expressing the lowest spatial frequencies at lower indices with the DC component being number 0 in the zigzag.
  • the higher frequency components contain the fine details of the image and are generally less sensitive to human vision, they can be quantized more coarsely than the low frequency components and may be discarded with negligible effect on image quality.
  • the quantized AC coefficients are then encoded using a Huffman coder.
  • Fig. 1 illustrates the JPEG compression algorithm
  • Fig. 2 illustrates the zigzag order of coefficient sequence.
  • the compressed data can then be stored (as in an electronic still camera) or transmitted efficiently over a limited band width communication network.
  • Reconstruction of the image requires a reverse process in which the headers and markers are extracted, the Huffman code is decoded, coefficients are dequantized, and an inverse DCT (IDCT) operation is performed on the coefficients.
  • IDCT inverse DCT
  • Image reconstruction out of a baseline JPEG- compatible file is a function of the number of pixels in the image and can be time consuming. Progressive construction of the image can be effected through spectral selection, successive approximation, and hierarchical coding.
  • baseline JPEG coded data the user must decode all image data for image reconstruction. This process can be time consuming, especially if the user wants to quickly browse various images when seeking a specific image.
  • a method for accelerating the decoding process and reconstructing partial images to facilitate a quick survey of images based on baseline JPEG coded data.
  • the process eliminates zero-quantized high-frequency coefficients and can use only DC coefficients which are dequantized to obtain unsigned numbers.
  • the unsigned numbers are then used to generate an image which is equal to the original image size decimated by 8 in two dimensions (i.e., - - size) and which is built out of the biased DC values of each block.
  • the invention can be implemented in a JPEG decoder which first Huffman decodes the compressed image data stream.
  • the quantized DC coefficient is generated out of the differential DC value with the quantized DC value then dequantized and biased to generate an unsigned value which is used for displaying the image.
  • the remainder of the block which contains AC values is not used and need not be dequantized.
  • the unsigned bias DC values are produced each time a block of data completes the de-Huffman process without requiring DCT.
  • Fig. 1 is a functional block diagram illustrating a compression/decompression algorithm.
  • Fig. 2 illustrates the zigzag order of coefficient sequence in an 8x8 array of DCT coefficients.
  • Fig. 3 is a flow diagram illustrating the imaging process based on dequantized DC coefficient using a JPEG decoder in accordance with the invention.
  • Fig. 1 is a functional block diagram of the compression/decompression implemented with a JPEG coder/decoder such as the ZR36040 product of Zoran Corporation, assignee, and Fig. 2 illustrates the zigzag sequence of an 8x8 array of quantized DCT coefficients used for "coding."
  • the DC coefficient is coefficient 0 and the higher frequency coefficients are the higher numbers. Because the higher frequency components contain the fine details of the image and are generally less sensitive to human vision, they can be quantized more forcefully than the lower frequency components and may be discarded with negligible effect on image quality. In coding, the coarser quantization of high frequency coefficients results in long strings of zeros in the coded image data.
  • thumbnail or reduced size images are generated based on the DC values of the DCT coded image data.
  • the compressed DCT coded data must first be decoded with a Huffman decoder, where the non-zero quantized coefficients are generated out of the Huffman coded data. This step is proportional in processing time to the number of non-zero quantized coefficients.
  • the quantized DC value is then generated out of the differential DC values and is dequantized and biased to generate the DCT coefficient ' which is used for the thumbnail image. This step takes one clock period since only one coefficient (DC coefficient) is going through the stage.
  • FIG. 3 is a flow diagram illustrating the imaging process based on dequantized DC coefficients with a JPEG decoder in accordance with the invention.
  • the relative time it takes to decode the image and generate the thumbnail image is the number of non-zero quantized coefficients divided by the image size.
  • the extreme case is a compressed file which contains only DC values with all the AC values being zero.
  • EOB end of block
  • the invention has been implemented using the Zoran 36040 JPEG Image Coder/Decoder in which the compressed bit-stream is first Huffman decoded and then the quantized DC coefficients are generated out of the differential DC value.
  • the quantized DC value is then dequantized and biased to generate an unsigned value, which is then used for displaying the image.
  • the rest of the block of data containing the AC values is skipped and there is no need to dequantize all of the AC values and execute the inverse DCT operation.
  • the unsigned biased DC values are output every time a block completes its de-Huffman process, which facilitates the imaging of data for quick scanning.
  • the process of generating the thumbnail is therefore part of the regular decoding process, requiring no special logic. The later part of the process is skipped.

Abstract

Thumbnail images are constructed out of a baseline JPEG compressed image signal using only the differential DC values while suppressing all non-zero AC values. The resulting image has reduced size which is sufficient for many scanning purposes. The differential DC values are used to obtain quantized DC values which are dequantized and biased to get unsigned numbers.

Description

RAPID THUMBNAIL IMAGE RECONSTRUCTION OF DCT COMPRESSED IMAGE DATA
BACKGROUND OF THE INVENTION This invention relates generally to image compression, and more particularly the invention relates to discrete cosine transform (DCT) -based compression and coding of images and image reconstruction therefrom.
Image compression is used in reducing large volumes of data in digitized images for convenient and economical storage and for transmission across communication networks having limited band width. Image compression technology is important in digital still video cameras, color scanners, color printers, color fax machines, computers, and multimedia.
The Joint Photographic Experts Group (JPEG) has established a color image data compression standard for use in a variety of still image applications. Compression employs
DCT-based processes operating on discrete blocks of the image. The DCT coefficients are then quantized based on the measurements of the threshold for visibility. For coding, an 8x8 pixel array of DCT coefficients is reorganized into a one- dimensional list using a zigzag sequence which tends to concentrate coefficients expressing the lowest spatial frequencies at lower indices with the DC component being number 0 in the zigzag. Because the higher frequency components contain the fine details of the image and are generally less sensitive to human vision, they can be quantized more coarsely than the low frequency components and may be discarded with negligible effect on image quality. The quantized AC coefficients are then encoded using a Huffman coder. Finally, headers and markers are inserted in the codes for individual blocks along with bit and byte stuffings for JPEG data compatibility. Fig. 1 illustrates the JPEG compression algorithm, and Fig. 2 illustrates the zigzag order of coefficient sequence. The compressed data can then be stored (as in an electronic still camera) or transmitted efficiently over a limited band width communication network. Reconstruction of the image requires a reverse process in which the headers and markers are extracted, the Huffman code is decoded, coefficients are dequantized, and an inverse DCT (IDCT) operation is performed on the coefficients.
Image reconstruction out of a baseline JPEG- compatible file is a function of the number of pixels in the image and can be time consuming. Progressive construction of the image can be effected through spectral selection, successive approximation, and hierarchical coding. However, in baseline JPEG coded data, the user must decode all image data for image reconstruction. This process can be time consuming, especially if the user wants to quickly browse various images when seeking a specific image.
SUMMARY OF THE INVENTION In accordance with the present invention, a method is provided for accelerating the decoding process and reconstructing partial images to facilitate a quick survey of images based on baseline JPEG coded data. The process eliminates zero-quantized high-frequency coefficients and can use only DC coefficients which are dequantized to obtain unsigned numbers. The unsigned numbers are then used to generate an image which is equal to the original image size decimated by 8 in two dimensions (i.e., - - size) and which is built out of the biased DC values of each block.
The invention can be implemented in a JPEG decoder which first Huffman decodes the compressed image data stream.
The quantized DC coefficient is generated out of the differential DC value with the quantized DC value then dequantized and biased to generate an unsigned value which is used for displaying the image. The remainder of the block which contains AC values is not used and need not be dequantized. The unsigned bias DC values are produced each time a block of data completes the de-Huffman process without requiring DCT. The invention and objects and features thereof will be more fully apparent from the following detailed description and appended claims with taken with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a functional block diagram illustrating a compression/decompression algorithm.
Fig. 2 illustrates the zigzag order of coefficient sequence in an 8x8 array of DCT coefficients. Fig. 3 is a flow diagram illustrating the imaging process based on dequantized DC coefficient using a JPEG decoder in accordance with the invention.
DESCRIPTION OF ILLUSTRATIVE EMBODIMENT Fig. 1 is a functional block diagram of the compression/decompression implemented with a JPEG coder/decoder such as the ZR36040 product of Zoran Corporation, assignee, and Fig. 2 illustrates the zigzag sequence of an 8x8 array of quantized DCT coefficients used for "coding." The DC coefficient is coefficient 0 and the higher frequency coefficients are the higher numbers. Because the higher frequency components contain the fine details of the image and are generally less sensitive to human vision, they can be quantized more forcefully than the lower frequency components and may be discarded with negligible effect on image quality. In coding, the coarser quantization of high frequency coefficients results in long strings of zeros in the coded image data.
In accordance with the present invention, thumbnail or reduced size images are generated based on the DC values of the DCT coded image data. The compressed DCT coded data must first be decoded with a Huffman decoder, where the non-zero quantized coefficients are generated out of the Huffman coded data. This step is proportional in processing time to the number of non-zero quantized coefficients. The quantized DC value is then generated out of the differential DC values and is dequantized and biased to generate the DCT coefficient' which is used for the thumbnail image. This step takes one clock period since only one coefficient (DC coefficient) is going through the stage.
The remainder of the process, including the dequantization of the quanitized AC coefficients and the IDCT, is skipped. Fig. 3 is a flow diagram illustrating the imaging process based on dequantized DC coefficients with a JPEG decoder in accordance with the invention.
The relative time it takes to decode the image and generate the thumbnail image is the number of non-zero quantized coefficients divided by the image size. The extreme case is a compressed file which contains only DC values with all the AC values being zero. In this case, since an end of block (EOB) is stored also, the generation of the thumbnail image takes about 3% of the time required to decompress the full image.
The invention has been implemented using the Zoran 36040 JPEG Image Coder/Decoder in which the compressed bit-stream is first Huffman decoded and then the quantized DC coefficients are generated out of the differential DC value. As noted above, the quantized DC value is then dequantized and biased to generate an unsigned value, which is then used for displaying the image. The rest of the block of data containing the AC values is skipped and there is no need to dequantize all of the AC values and execute the inverse DCT operation. The unsigned biased DC values are output every time a block completes its de-Huffman process, which facilitates the imaging of data for quick scanning. The process of generating the thumbnail is therefore part of the regular decoding process, requiring no special logic. The later part of the process is skipped.
While the invention has been described with reference to a specific embodiment, the description is illustrative of the invention and is not to be construed as limiting the invention. Various modifications and applications may occur to those skilled in the art without departing from the true spirit and scope of the invention as defined by the appended claims.

Claims

WHAT IS CLAIMED IS;
1. A method of rapidly generating images of a reduced size using Huffman encoded discrete cosine transform (DCT) coefficients of compressed image signals comprising the steps of a) decoding said compressed image signals using a Huffman decoder, thereby generating non-zero quantized coefficients and differential DC values, b) generating quantized DC values from said differential DC values, c) dequantizing said quantized DC values to obtain biased unsigned DC values, and d) generating images using said biased unsigned DC values.
2. The method as defined by claim 1 wherein said Huffman encoded discrete cosine transform coefficients comprise JPEG compressed image signals and steps a) , b) , and c) are performed in a JPEG decoder.
3. The method as defined by claim 2 wherein said compressed image signals are based on an 8x8 array of DCT coefficients and each of said images using said biased unsigned DC values is - -- of a full image.
4. Apparatus for rapid thumbnail image reconstruction of Huffman encoded discrete cosine transform (DCT) coefficients of compressed image signals comprising means for decoding said compressed image signals using a Huffman decoder, thereby generating non-zero quantized coefficients and differential DC values, means for generating quantized DC values from said differential DC values, means for dequantizing said quantized DC values to obtain biased unsigned DC values, and means for generating images using only said biased unsigned DC values.
5. Apparatus as defined by claim 4 wherein said means for decoding is a JPEG decoder.
PCT/US1994/002914 1993-03-23 1994-03-17 Rapid thumbnail image reconstruction of dct compressed image data WO1994022108A1 (en)

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US3599493A 1993-03-23 1993-03-23
US08/035,994 1993-03-23

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Cited By (19)

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EP0796013A2 (en) * 1996-03-14 1997-09-17 Matsushita Electric Industrial Co., Ltd. Video image processing apparatus and the method of the same
EP0810794A2 (en) * 1996-05-30 1997-12-03 Nippon Telegraph And Telephone Corporation Video editing scheme using icons directly obtained from coded video data
US5699458A (en) * 1995-06-29 1997-12-16 Intel Corporation Efficient browsing of encoded images
EP0873008A2 (en) * 1997-04-16 1998-10-21 Seiko Epson Corporation Highspeed image selecting method and digital still picture camera having highspeed image selecting function
WO1999016250A1 (en) * 1997-09-23 1999-04-01 Telefonaktiebolaget Lm Ericsson (Publ) An embedded dct-based still image coding algorithm
US6058417A (en) * 1998-10-23 2000-05-02 Ebay Inc. Information presentation and management in an online trading environment
EP1087397A2 (en) * 1995-07-14 2001-03-28 Matsushita Electric Industrial Co., Ltd. Image editing apparatus
WO2002041638A2 (en) * 2000-11-16 2002-05-23 Koninklijke Philips Electronics N.V. Scalable mpeg-2 video system
US6804405B2 (en) 1998-10-09 2004-10-12 Telefonaktiebolaget Lm Ericsson (Publ) Method and a system for coding rois
AU2002304037B2 (en) * 1997-01-09 2005-09-15 Canon Kabushiki Kaisha A Method and Apparatus for Compressing and Scaling Thumbnails
EP1667457A1 (en) * 2003-09-16 2006-06-07 Fujitsu Limited Image processing display device and image processing display method
EP1788796A1 (en) * 2004-08-30 2007-05-23 Fujitsu Limited Image restoration device, image restoration method, and image restoration program
US7836091B2 (en) 2003-12-19 2010-11-16 Sharp Laboratories Of America, Inc. Systems and methods for providing access to an embedded thumbnail image
US8005305B2 (en) 2003-06-16 2011-08-23 Oce-Technologies B.V. Method and apparatus for generating a halftoned image from a compressed image
US8335983B2 (en) 2000-06-07 2012-12-18 Ebay, Inc. Dynamic selection of images for web pages
US9076239B2 (en) 2009-04-30 2015-07-07 Stmicroelectronics S.R.L. Method and systems for thumbnail generation, and corresponding computer program product
WO2019143387A1 (en) * 2018-01-19 2019-07-25 Google Llc Two-pass decoding of baseline images
CN111567041A (en) * 2018-07-13 2020-08-21 瑞典爱立信有限公司 Transform selection in video encoder and/or video decoder
US20230070744A1 (en) * 2011-10-14 2023-03-09 Advanced Micro Devices, Inc. Region-based image decompression

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US5699458A (en) * 1995-06-29 1997-12-16 Intel Corporation Efficient browsing of encoded images
EP1087397B1 (en) * 1995-07-14 2005-11-30 Matsushita Electric Industrial Co., Ltd. Image editing apparatus
EP0753852B1 (en) * 1995-07-14 2001-10-17 Matsushita Electric Industrial Co., Ltd. Image editing apparatus
EP1087397A2 (en) * 1995-07-14 2001-03-28 Matsushita Electric Industrial Co., Ltd. Image editing apparatus
EP0796013A3 (en) * 1996-03-14 1998-11-04 Matsushita Electric Industrial Co., Ltd. Video image processing apparatus and the method of the same
EP0796013A2 (en) * 1996-03-14 1997-09-17 Matsushita Electric Industrial Co., Ltd. Video image processing apparatus and the method of the same
US5990976A (en) * 1996-03-14 1999-11-23 Matsushita Electric Industrial Co., Ltd. Video image processing apparatus and the method of the same
US6192183B1 (en) 1996-05-30 2001-02-20 Nippon Telegraph And Telephone Corporation Video editing scheme using icons directly obtained from coded video data
EP0810794A2 (en) * 1996-05-30 1997-12-03 Nippon Telegraph And Telephone Corporation Video editing scheme using icons directly obtained from coded video data
EP0810794A3 (en) * 1996-05-30 1999-09-22 Nippon Telegraph And Telephone Corporation Video editing scheme using icons directly obtained from coded video data
AU2002304037B2 (en) * 1997-01-09 2005-09-15 Canon Kabushiki Kaisha A Method and Apparatus for Compressing and Scaling Thumbnails
US8237840B2 (en) 1997-04-16 2012-08-07 Seiko Epson Corporation High speed image selecting method and digital camera having high speed image selecting function
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US6445412B1 (en) 1997-04-16 2002-09-03 Seiko Epson Corporation Highspeed image selecting method and digital camera having highspeed image selecting function
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US8339496B2 (en) 1997-04-16 2012-12-25 Seiko Epson Corporation Highspeed image selecting method and digital camera having highspeed image selecting function
US8917344B2 (en) 1997-04-16 2014-12-23 Seiko Epson Corporation Highspeed image selecting method digital camera having highspeed image selecting function
US8350947B2 (en) 1997-04-16 2013-01-08 Seiko Epson Corporation High speed image selecting method digital camera having high speed image selecting function
WO1999016250A1 (en) * 1997-09-23 1999-04-01 Telefonaktiebolaget Lm Ericsson (Publ) An embedded dct-based still image coding algorithm
US6804405B2 (en) 1998-10-09 2004-10-12 Telefonaktiebolaget Lm Ericsson (Publ) Method and a system for coding rois
US6415320B1 (en) 1998-10-23 2002-07-02 Ebay Inc. Information presentation and management in an online trading environment
US6732161B1 (en) 1998-10-23 2004-05-04 Ebay, Inc. Information presentation and management in an online trading environment
EP1131724A1 (en) * 1998-10-23 2001-09-12 Ebay, Inc. Information presentation and management in an online trading environment
EP1131724A4 (en) * 1998-10-23 2002-01-30 Ebay Inc Information presentation and management in an online trading environment
US6058417A (en) * 1998-10-23 2000-05-02 Ebay Inc. Information presentation and management in an online trading environment
US9477773B2 (en) 2000-06-07 2016-10-25 Ebay Inc. Automated selection of images for web pages
US8335983B2 (en) 2000-06-07 2012-12-18 Ebay, Inc. Dynamic selection of images for web pages
US9116868B2 (en) 2000-06-07 2015-08-25 Ebay, Inc. Automated selection of images for web pages
WO2002041638A2 (en) * 2000-11-16 2002-05-23 Koninklijke Philips Electronics N.V. Scalable mpeg-2 video system
US6580759B1 (en) 2000-11-16 2003-06-17 Koninklijke Philips Electronics N.V. Scalable MPEG-2 video system
WO2002041638A3 (en) * 2000-11-16 2002-10-10 Koninkl Philips Electronics Nv Scalable mpeg-2 video system
US8005305B2 (en) 2003-06-16 2011-08-23 Oce-Technologies B.V. Method and apparatus for generating a halftoned image from a compressed image
EP1667457A4 (en) * 2003-09-16 2011-11-16 Fujitsu Semiconductor Ltd Image processing display device and image processing display method
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US7836091B2 (en) 2003-12-19 2010-11-16 Sharp Laboratories Of America, Inc. Systems and methods for providing access to an embedded thumbnail image
EP1788796A4 (en) * 2004-08-30 2010-03-24 Fujitsu Microelectronics Ltd Image restoration device, image restoration method, and image restoration program
EP1788796A1 (en) * 2004-08-30 2007-05-23 Fujitsu Limited Image restoration device, image restoration method, and image restoration program
US9652818B2 (en) 2009-04-30 2017-05-16 Stmicroelectronics S.R.L. Method and systems for thumbnail generation, and corresponding computer program product
US9076239B2 (en) 2009-04-30 2015-07-07 Stmicroelectronics S.R.L. Method and systems for thumbnail generation, and corresponding computer program product
US9105111B2 (en) 2009-04-30 2015-08-11 Stmicroelectronics S.R.L. Method and systems for thumbnail generation, and corresponding computer program product
US20230070744A1 (en) * 2011-10-14 2023-03-09 Advanced Micro Devices, Inc. Region-based image decompression
CN111492656A (en) * 2018-01-19 2020-08-04 谷歌有限责任公司 Two-stage decoding of baseline images
US11341686B2 (en) 2018-01-19 2022-05-24 Google Llc Two-pass decoding of images
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WO2019143387A1 (en) * 2018-01-19 2019-07-25 Google Llc Two-pass decoding of baseline images
CN111567041A (en) * 2018-07-13 2020-08-21 瑞典爱立信有限公司 Transform selection in video encoder and/or video decoder
US11218716B2 (en) 2018-07-13 2022-01-04 Telefonaktiebolaget Lm Ericsson (Publ) Transform selection in a video encoder and/or video decoder
CN111567041B (en) * 2018-07-13 2022-04-29 瑞典爱立信有限公司 Transform selection in video encoder and/or video decoder
US11882302B2 (en) 2018-07-13 2024-01-23 Telefonaktiebolaget Lm Ericsson (Publ) Transform selection in a video encoder and/or video decoder
US11627329B2 (en) 2018-07-13 2023-04-11 Telefonaktiebolaget Lm Ericsson (Publ) Transform selection in a video encoder and/or video decoder

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