A JPEG variable quantization method for compound documents

Κωνσταντινίδης, Κωνσταντίνος; Tretter, Daniel

doi:10.1109/83.847840

Cited by 26 publications

(17 citation statements)

References 10 publications

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“…Algorithm II uses the segmentation algorithm of [8] to classify each image block as background, text or picture. However, in principle, Algorithm II can be used in conjunction with any preprocessing segmentation procedure that labels each block as background, text, or picture.…”

Section: Resultsmentioning

confidence: 99%

“…The first feature component is based on the encoding length proposed in [8], [30]. The encoding length of a block is defined as the number of bits in the JPEG stream used to encode the block.…”

Section: Block-based Segmentationmentioning

confidence: 99%

“…One approach is to adjust the bit usage of the image blocks during encoding [6]- [8]. In this approach, the bit rate is adjusted in accordance to the content of the blocks so as to achieve better rate-distortion characteristics.…”

mentioning

confidence: 99%

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A Document Image Model and Estimation Algorithm for Optimized JPEG Decompression

Wong

Bouman

Pollak

et al. 2009

IEEE Trans. on Image Process.

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Abstract-The JPEG standard is one of the most prevalent image compression schemes in use today. While JPEG was designed for use with natural images, it is also widely used for the encoding of raster documents. Unfortunately, JPEG's characteristic blocking and ringing artifacts can severely degrade the quality of text and graphics in complex documents. We propose a JPEG decompression algorithm which is designed to produce substantially higher quality images from the same standard JPEG encodings. The method works by incorporating a document image model into the decoding process which accounts for the wide variety of content in modern complex color documents. The method works by first segmenting the JPEG encoded document into regions corresponding to background, text, and picture content. The regions corresponding to text and background are then decoded using maximum a posteriori (MAP) estimation. Most importantly, the MAP reconstruction of the text regions uses a model which accounts for the spatial characteristics of text and graphics. Our experimental comparisons to the baseline JPEG decoding as well as to three other decoding schemes, demonstrate that our method substantially improves the quality of decoded images, both visually and as measured by PSNR.

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Section: Resultsmentioning

confidence: 99%

Section: Block-based Segmentationmentioning

confidence: 99%

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A Document Image Model and Estimation Algorithm for Optimized JPEG Decompression

Wong

Bouman

Pollak

et al. 2009

IEEE Trans. on Image Process.

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show abstract

“…Fortunately, there is still some control on the parameters of the JPEG algorithm to adapt it for different image types. Compression of images with different contents by varying these parameters has received significant attention in the recent past [3,4,5].…”

Section: Introductionmentioning

confidence: 99%

Improving mobile color 2D-barcode JPEG image readability using DCT coefficient distributions

Tan

Chai

2012

2012 International Conference on Audio, Language and Image Processing

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Two dimensional (2D) barcodes are becoming a pervasive interface for mobile devices, such as camera smartphones. Often, only monochrome 2D-barcodes are used due to their robustness in an uncontrolled operating environment of smartphones. Nonetheless, we are seeing an emerging use of color 2D-barcodes for camera smartphones. Most smartphones capture and store such 2D-barcode images in the baseline JPEG format. As a lossy compression technique, JPEG does introduce a fair amount of error in the captured 2D-barcode images. In this paper, we analyzed the Discrete Cosine Transform (DCT) coefficient distributions of generalized 2D-barcodes using colored data cells, each comprising of 4, 8 and 10 colors. Using these DCT distributions, we improved the JPEG compression of such mobile barcode images. By altering the JPEG compression parameters based on the DCT coefficient distribution of the barcode images, our improved compression scheme produces JPEG images with higher PSNR value as compared to the baseline implementation. We have also applied our improved scheme to a 10 colors 2D-barcode system; and analyzed its performance in comparison to the default and alternative JPEG schemes. We have found that our improved scheme does provide a marked improvement for the successful decoding of the 10 colors 2D-barcode system.

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“…The alternative is block-based segmentation proposed in [9], [10], and [11], but yields poor quality for the blocks that cross the boundary of pictures and text. The compression of computergenerated compound images was investigated in JPEG variable quantization method [12], modified JPEG-LS [13], and lossless coder using intraplane and interplane coding [14]. However, totally lossy or lossless compression can not provide the content-adaptivity to compound images thus reproduces text/graphics blurred or otherwise achieves little coding gains.…”

Section: Introductionmentioning

confidence: 99%

Hybrid image coding for real-time computer screen video transmission

et al. 2004

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In this paper, we present a novel hybrid image coding scheme for real-time applications of computer screen video transmission. Based on the Mixed Raster Content (MRC) multilayer imaging model, the background picture is compressed with lossy JPEG, and the foreground layer consisting of text and graphics is compressed with a block-based lossless coding algorithm, which integrates shape-based coding, palette-based coding, palette reuse, and LZW algorithm. The key technique is to extract text and graphics from background pictures accurately and with low complexity. Shape primitives, such as lines, rectangles, and isolated pixels with prominent colors, are found to be significant clues for textual and graphical contents. The shape-based coding in our lossless algorithm provides intelligence to extract the computer-generated text and graphics elegantly and easily. Experimental results demonstrate the efficiency and low complexity of our proposed hybrid image coding scheme.

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A JPEG variable quantization method for compound documents

Cited by 26 publications

References 10 publications

A Document Image Model and Estimation Algorithm for Optimized JPEG Decompression

A Document Image Model and Estimation Algorithm for Optimized JPEG Decompression

Improving mobile color 2D-barcode JPEG image readability using DCT coefficient distributions

Hybrid image coding for real-time computer screen video transmission

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