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Improved method for predicting the peak signal-to-noise ratio quality of decoded images in fractal image coding

JOURNAL OF ELECTRONIC IMAGING 2017年第1期26卷 013024-013024页

作者： Wang, Qiang Bi, Sheng Dalian Maritime Univ Coll Informat Sci & Technol Dalian Peoples R China

To predict the peak signal-to-noise ratio (PSNR) quality of decoded images in fractal image coding more efficiently and accurately, an improved method is proposed. After some derivations and analyses, we find that the linear correlation coefficients between coded range blocks and their respective best-matched domain blocks can determine the dynamic range of their collage errors, which can also provide the minimum and the maximum of the accumulated collage error (ACE) of uncoded range blocks. Moreover, the dynamic range of the actual percentage of accumulated collage error (APACE), APACEmin to APACEmax, can be determined as well. When APACEmin reaches a large value, such as 90%, APACEmin to APACEmax will be limited in a small range and APACE can be computed approximately. Furthermore, with ACE and the approximate APACE, the ACE of all range blocks and the average collage error (ACER) can be obtained. Finally, with the logarithmic relationship between ACER and the PSNR quality of decoded images, the PSNR quality of decoded images can be predicted directly. Experiments show that compared with the previous similar method, the proposed method can predict the PSNR quality of decoded images more accurately and needs less computation time simultaneously. (C) 2017 SPIE and IS&T

关键词： fractal image coding average collage error peak signal-to-noise ratio quality of decoded images

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Modified decoded image quality prediction method for fractal image coding

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COMPUTERS & ELECTRICAL ENGINEERING 2024年第PartB期118卷

作者： Wang, Qiang Du, Jingjing Dalian Maritime Univ Coll Informat Sci & Technol Linghai Rd 1 Dalian 116026 Peoples R China Hengshui Univ Coll Elect & Informat Engn Hengshui 053000 Peoples R China

An effective method was proposed to improve the performance of fractal decoded image quality prediction. Firstly, we found that the dynamic range of the linear correlation coefficients (LCCs) between range blocks and their respective best-matched domain blocks was significantly extended by a small number of outliers which contribute little to accumulated collage error and reduced the prediction accuracy. Secondly, to remove the outliers of LCCs, we introduced the effective minimum and maximum of LCCs that can provide the effective bottom and top limits of the actual percentage of accumulated collage error (APACE), EBL-APACE and ETL-APACE, respectively. Finally, by estimating APACE with the average of EBL-APACE and ETL-APACE, the decoded image quality can be directly predicted with the accumulated collage error divided by the estimated APACE. Three state-of-the-art and conventional fractal encoding methods were adopted to verify the effectiveness of the proposed method. Experimental results show that the proposed method can reduce the computational complexity by 2%-7% while maintaining comparable or higher prediction accuracy regarding the previous method.

关键词： fractal image coding Decoded image quality Accumulated collage error Average collage error

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Huber fractal image coding Based on a Fitting Plane

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IEEE TRANSACTIONS ON image PROCESSING 2013年第1期22卷 134-145页

作者： Lu, Jian Ye, Zhongxing Zou, Yuru Shenzhen Univ Coll Math & Computat Sci Shenzhen 518060 Peoples R China Shanghai Jiao Tong Univ Dept Math Shanghai 200240 Peoples R China

Recently, there has been significant interest in robust fractal image coding for the purpose of robustness against outliers. However, the known robust fractal coding methods (HFIC and LAD-FIC, etc.) are not optimal, since, besides the high computational cost, they use the corrupted domain block as the independent variable in the robust regression model, which may adversely affect the robust estimator to calculate the fractal parameters (depending on the noise level). This paper presents a Huber fitting plane-based fractal image coding (HFPFIC) method. This method builds Huber fitting planes (HFPs) for the domain and range blocks, respectively, ensuring the use of an uncorrupted independent variable in the robust model. On this basis, a new matching error function is introduced to robustly evaluate the best scaling factor. Meanwhile, a median absolute deviation (MAD) about the median decomposition criterion is proposed to achieve fast adaptive quadtree partitioning for the image corrupted by salt & pepper noise. In order to reduce computational cost, the no-search method is applied to speedup the encoding process. Experimental results show that the proposed HFPFIC can yield superior performance over conventional robust fractal image coding methods in encoding speed and the quality of the restored image. Furthermore, the no-search method can significantly reduce encoding time and achieve less than 2.0 s for the HFPFIC with acceptable image quality degradation. In addition, we show that, combined with the MAD decomposition scheme, the HFP technique used as a robust method can further reduce the encoding time while maintaining image quality.

关键词： fractal image coding Huber fitting plane median absolute deviation ( MAD) decomposition criterion robust regression

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Feature Difference Classification Method in fractal image coding

Feature Difference Classification Method in Fractal Image Co...

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2002年第6届信号处理国际会议

作者： Chen Yisong, Wang Guoping, Dong Shihai HCI & Multimedia Lab of Peking University, Peking, 100871

In this paper, we present a classification algorithm in fractal image coding. Based on the contraction characteristics of transformations in fractal image coding, the algorithm uses the notion of feature difference to speed up the domain-range matching routine of the coding. The algorithm can effectively exclude pseudo matches during the process of domain-range matching and result in significant improvement of the rate-distortion performance. It can also be easily realized in cooperation with many other speedup schemes.

关键词： fractal image coding Classification Domain-range match.

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An Effective Improvement on fractal image coding With Same-Sized Block Mapping

An Effective Improvement on Fractal Image Coding With Same-S...

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2002年第6届信号处理国际会议

作者： SUN Yunda, SONG Changhui, ZHAO Yao Institute of Information Science, Northern Jiaotong University, Beijing 100044, China

Some influential fractal methods are first discussed in this paper. Then a dual-classification technique is used to optimize the Same-Sized Block Mapping scheme. leading to considerable speed-up with no loss in fidelity. The process of our FX(HX) scheme is also proposed in detail. Finally, the good performance can be seen in experimental results.

关键词： fractal image coding Same-Sized Block Mapping dual-classification

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Perceptual image hashing based on structural fractal features of image coding and ring partition

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MULTIMEDIA TOOLS AND APPLICATIONS 2020年第27-28期79卷 19025-19044页

作者： Khelaifi, Fares He, HongJie Southwest Jioatong Univ Sch Informat Sci & Technol Chengdu 610031 Peoples R China

Perceptual image hashing finds increasing attention in several multimedia security applications. However, reaching the trade-off balance between the two most important properties of image hashing- robustness and discrimination, still remains the most restive challenge in hashing schemes. In this study, a robust image hashing technique is proposed by incorporating ring partition and fractal image coding. The scheme starts by normalizing the image to help in extracting its local features. Then the concept of ring partition is introduced in order to make our hash rotation invariant by dividing the image into 5 different rings to form a secondary image that possesses the invariant property. Further, image coding is introduced by extracting the structural fractal features to exploit dimensionality reduction and compression, hence, generating a robust hash. To ensure the system's security, encryption is performed on the generated fractal elements before the final hash construction. We conduct series of experiments to evaluate the performance of our scheme. The achieved result shows that our scheme is robust against several content-preserving attacks such as image rotation, JPEG compression, gamma correction, gaussian low pass filtering, image scaling, cropping, brightness adjustment and contrast adjustment. In addition, the receiver operating characteristics is used to show the discriminative capability and robustness of our scheme as compared to other state-of-art schemes in the literature.

关键词： Perceptual image hashing Ring partition Feature extraction fractal image coding Hash generation

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An adaptive fractal-based image coding with hierarchical classification strategy and its modifications

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INNOVATIONS IN SYSTEMS AND SOFTWARE ENGINEERING 2019年第1期15卷 35-42页

作者： Nandi, Utpal Vidyasagar Univ Dept Comp Sci Midnapore 721102 W Bengal India

fractal-based image coding is one of the efficient methods for grayscale image since the reconstructed images are resolution independent and also has low reconstruction time. This paper discusses the efficiency of hierarchical classification strategy for fractal image coding that uses adaptive quadtree partitioning. The scheme forms two level hierarchical domain groups and ranges are matched with similar hierarchical domain class. The fractal image coding technique with hierarchical classification strategy is then modified also to improve the compression ratio by using an efficient loss-less coding scheme OLZW on fractal compressed image. A variant of OLZW, i.e., MOLZW is also applied for the same. These modified variants show their significant improvements in compression ratio without degradation of image quality.

关键词： fractal image coding Hierarchical classification PSNR Loss-less coding Adaptive quadtree partitioning

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An efficient fractal image-coding method using interblock correlation search

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY 2001年第2期11卷 257-261页

作者： Wang, CC Hsieh, CH Chung Cheng Inst Technol Dept Elect Engn Tao Yuan 33509 Taiwan I Shou Univ Kaohsiung 84004 Taiwan

An efficient fractal image-coding method that exploits the correlation between range blocks is proposed. Four domain blocks mapped by the previous neighboring range blocks are considered as the good candidate blocks of the input range block. Experimental results show that when the proposed method is implemented with a fast fractal coding algorithm, it can further reduce the encoding time and bit rate with insignificant loss of image quality.

关键词： correlation search fractal image coding image compression search-order coding

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Efficient Quadtree based fractal image coding Scheme in Wavelet Transform Domain *

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Journal of Southeast University(English Edition) 1998年第1期14卷 35-40页

作者：高西奇洪波张辉何振亚东南大学无线电工程系

This paper presents an efficient quadtree based fractal image coding scheme in wavelet transform domain based on the wavelet based theory of fractal image compression introduced by Davis. In the scheme, zerotrees of wavelet coefficients are used to reduce the number of domain blocks, which leads to lower bit cost required to represent the location information of fractal coding, and overall entropy constrained optimization is performed for the decision trees as well as for the sets of scalar quantizers and self quantizers of wavelet subtrees. Experiment results show that at the low bit rates, the proposed scheme gives about 1 dB improvement in PSNR over the reported results.

关键词： fractal image coding wavelet transform quadtree

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Fast fractal image coding method using the characteristics of human vision system in DCT domain

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Jisuanji Fuzhu Sheji Yu Tuxingxue Xuebao/Journal of Computer-Aided Design and Computer Graphics 2005年第1期17卷 67-73页

作者： Feng, Lin Li, Yanjun Shao, Gang Wang, Xiukun Teng, Hongfei Inst. of Mech. Eng. Dalian Univ. of Technol. Dalian 116024 China Inst. of Univ. Students' Innovation Dalian Univ. of Technol. Dalian 116024 China

Considering the characteristics of human visual system, this paper presents a plain block selecting standard in DCT domain based on visual acuity. This standard excels the frequently used block variance and SNR measurements. Based on the standard, the computational complexity of the fractal image compression is reduced by selecting out the uniform parts in the DCT domain and encoding output the direct current directly without any fractal matching. For encoding time further reducing, the frequency response of human visual system is introduced in the DCT domain to classify the picture blocks and similar blocks and the visual effects of the decoded images are guaranteed in the matching computation of redundancy filtering. Experiment shows that provided with the same compression ratio, the encoding time is greatly reduced with improved PSNR and much better visual effect.

关键词： DCT fractal image coding Human vision system (HVS) Plain block

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