A still image coding method in which AR model estimation is applied to dct coefficients of edge blocks

In recent years, wavelets have attracted great attention in both still image compression and video coding, and several novel wavelet-based image compression algorithms have been developed so far, one of which is Shapiro's embedded zerotree wavelet (EZW) image compression algorithm. However, there are still some deficiencies in this algorithm. In this paper, after the analysis of the deficiency in EZW, a new algorithm based on quantized coefficient partitioning using morphological operation is proposed. Instead of encoding the coefficients in each subband line-by-line, regions in which most of the quantized coefficients are significant are extracted by morphological dilation and encoded first. This is followed by using zerotrees to encode the remaining space which has mostly zeros. Experimental results show that the proposed algorithm is not only superior to the EZW, but also compares favorably with the most efficient wavelet-based image compression algorithms reported so far.

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CONTOUR BASED MULTI-ROI MULTI-QUALITY ROI CODING FOR STILL IMAGE

International Journal of Pattern Recognition and Artificial Intelligence ◽

10.1142/s0218001411008488 ◽

2011 ◽

Vol 25 (01) ◽

pp. 135-145 ◽

Cited By ~ 1

Author(s):

YAN ZHANG ◽

HAI-MING GU

Keyword(s):

Image Coding ◽

Region Of Interest ◽

Experimental Results ◽

Still Image ◽

Coding Schemes ◽

Coding Method ◽

Quality Image ◽

Roi Coding ◽

Region Of Interest Coding

Region-of-interest (ROI) image coding is one of the new features included in the JPEG2000 image coding standard. Two methods are defined in the standard: the Maxshift method and the generic scaling based method. In this paper, a new region-of-interest coding method called Contour-based Multi-ROI Multi-quality Image Coding (CMM) is proposed. Unlike other existing methods, the CMM method takes the contour and texture of the whole image as a special ROI, which makes the visually most important parts (in both ROI and Background) to be coded first. Experimental results indicate that the proposed method significantly outperforms the previous ROI coding schemes in the overall ROI coding performance.

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Fast Fractal Image Coding Method Based on RMSE and DCT Classification

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.241-244.3034 ◽

2012 ◽

Vol 241-244 ◽

pp. 3034-3039

Author(s):

Xian Qiang Lv ◽

Song Yang ◽

Xin Zhang ◽

Ying Wang ◽

Yun Feng Shi ◽

...

Keyword(s):

Image Coding ◽

Nearest Neighbor ◽

Search Space ◽

Image Block ◽

Fractal Image ◽

Coding Method ◽

Long Time ◽

Dct Coefficients ◽

Fractal Encoding ◽

Domain Block

To solve the problem of long time consuming in the fractal encoding process, a fast fractal encoding algorithm based on RMSE (Root mean square error) and DCT (Discrete Cosine Transform) classification is proposed. During the encoding process, firstly, the image is divided into range blocks and domain blocks by quadtree partition according to RMSE, then, according to DCT coefficients of image block, three classes of image blocks are defined, which are smooth class, horizontal/vertical edge class, diagonal/sub-diagonal class. At last, every range block is limited to search the best matched block in the corresponding domain block class, and the fractal coding are recorded until the process is completed. When searching the best matched block, the nearest neighbor block will be found in the sense of RMSE in the ordered codebook, and the best matched block will be further found in the vicinity of the nearest neighbor block. The experimental results show that the proposed algorithm can efficiently reduce the search space and shorten the encoding time, while achieving the same reconstructed image quality as that of the full search method.

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Non-linear contour-based multidirectional intra coding

APSIPA Transactions on Signal and Information Processing ◽

10.1017/atsip.2018.14 ◽

2018 ◽

Vol 7 ◽

Cited By ~ 1

Author(s):

Thorsten Laude ◽

Jan Tumbrägel ◽

Marco Munderloh ◽

Jörn Ostermann

Keyword(s):

Model Selection ◽

Image Coding ◽

Reference Area ◽

Selection Algorithm ◽

Still Image ◽

Intra Coding ◽

Coding Efficiency ◽

Contour Model ◽

Non Linear ◽

Contour Models

AbstractIntra coding is an essential part of all video coding algorithms and applications. Additionally, intra coding algorithms are predestined for an efficient still image coding. To overcome limitations in existing intra coding algorithms (such as linear directional extrapolation, only one direction per block, small reference area), we propose non-linear Contour-based Multidirectional Intra Coding. This coding mode is based on four different non-linear contour models, on the connection of intersecting contours and on a boundary recall-based contour model selection algorithm. The different contour models address robustness against outliers for the detected contours and evasive curvature changes. Additionally, the information for the prediction is derived from already reconstructed pixels in neighboring blocks. The achieved coding efficiency is superior to those of related works from the literature. Compared with the closest related work, BD rate gains of 2.16% are achieved on average.

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