To compress hyperspectral images, a low complexity discrete cosine transform （DCT）-based distributed source coding （DSC） scheme with Gray code is proposed. Unlike most of the existing DSC schemes, which utilize tr...To compress hyperspectral images, a low complexity discrete cosine transform （DCT）-based distributed source coding （DSC） scheme with Gray code is proposed. Unlike most of the existing DSC schemes, which utilize transform in spatial domain, the proposed algorithm applies transform in spectral domain. Set-partitioning-based approach is applied to reorganize DCT coefficients into waveletlike tree structure and extract the sign, refinement, and significance bitplanes. The extracted refinement bits are Gray encoded. Because of the dependency along the line dimension of hyperspectral images, low density paritycheck-（LDPC）-based Slepian-Wolf coder is adopted to implement the DSC strategy. Experimental results on airborne visible/infrared imaging spectrometer （AVIRIS） dataset show that the proposed paradigm achieves up to 6 dB improvement over DSC-based coders which apply transform in spatial domain, with significantly reduced computational complexity and memory storage.展开更多
As the wide application of imaging technology,the number of big image data which may containing private information is growing fast.Due to insufficient computing power and storage space for local server device,many pe...As the wide application of imaging technology,the number of big image data which may containing private information is growing fast.Due to insufficient computing power and storage space for local server device,many people hand over these images to cloud servers for management.But actually,it is unsafe to store the images to the cloud,so encryption becomes a necessary step before uploading to reduce the risk of privacy leakage.However,it is not conducive to the efficient application of image,especially in the Content-Based Image Retrieval(CBIR)scheme.This paper proposes an outsourcing privacy-preserving JPEG CBIR scheme.We design a set of JPEG format-compatible encryption method,making no file expansion to JPEG files.We firstly combine multiple adjacent 8×8 DCT coefficient blocks into big-blocks.Then,random scrambling and stream encryption are used on the binary code of DCT coefficients to protect the JPEG image privacy.The task of extracting features from encrypted images and retrieving similar images are done by the cloud server.The group index histograms of DCT coefficients are extracted from the encrypted big-blocks,then the global vector is produced to represent the JPEG image with the aid of bag-of-words(BOW)model.The security analysis and experimental results show that our proposed scheme has strong security and good retrieval performance.展开更多
The JPEG2000 image compression standard is the powerful encoder which can provide phenomenal rate-control performance.The post-compression rate-distortion(PCRD)algorithm in JPEG2000 is not efficient.It requires encodi...The JPEG2000 image compression standard is the powerful encoder which can provide phenomenal rate-control performance.The post-compression rate-distortion(PCRD)algorithm in JPEG2000 is not efficient.It requires encoding all coding passes even though a large contribution of them will not be contained in the final code-stream.Tier-1 encoding in the JPEG2000 standard takes a significant amount of memory and coding time.In this work,a low-complexity rate distortion method for JPEG2000 is proposed.It is relied on a reverse order for the resolution levels and the coding passes.The proposed algorithm encodes only the coding passes contained in the final code-stream and it does not need any post compression rate control part.The computational complexity of proposed algorithm is negligible,making it suitable to compression and attaining a significant performance.Simulations results show that the proposed algorithm obtained the PSNR values are comparable with the optimal PCRD.展开更多
Based on the ideas of controlling relative quality and rearranging bitplanes, a new ROI coding method for JPEG2000 was proposed, which shifts and rearranges bitplanes in units of bitplane groups. It can code arbitrary...Based on the ideas of controlling relative quality and rearranging bitplanes, a new ROI coding method for JPEG2000 was proposed, which shifts and rearranges bitplanes in units of bitplane groups. It can code arbitrary shaped ROI without shape coding, and reserve almost arbitrary percent of background information. It also can control the relative quality of progressive decoded images. In addition, it is easy to be implemented and has low computational cost.展开更多
In this paper, error-correction coding (ECC) in Gray codes is considered and its performance in the protecting of spatial image watermarks against lossy data compression is demonstrated. For this purpose, the differen...In this paper, error-correction coding (ECC) in Gray codes is considered and its performance in the protecting of spatial image watermarks against lossy data compression is demonstrated. For this purpose, the differences between bit patterns of two Gray codewords are analyzed in detail. On the basis of the properties, a method for encoding watermark bits in the Gray codewords that represent signal levels by a single-error-correcting (SEC) code is developed, which is referred to as the Gray-ECC method in this paper. The two codewords of the SEC code corresponding to respective watermark bits are determined so as to minimize the expected amount of distortion caused by the watermark embedding. The stochastic analyses show that an error-correcting capacity of the Gray-ECC method is superior to that of the ECC in natural binary codes for changes in signal codewords. Experiments of the Gray-ECC method were conducted on 8-bit monochrome images to evaluate both the features of watermarked images and the performance of robustness for image distortion resulting from the JPEG DCT-baseline coding scheme. The results demonstrate that, compared with a conventional averaging-based method, the Gray-ECC method yields watermarked images with less amount of signal distortion and also makes the watermark comparably robust for lossy data compression.展开更多
基金supported by the National Natural Science Foundationof China (60702012)the Scientific Research Foundation for the Re-turned Overseas Chinese Scholars, State Education Ministry
文摘To compress hyperspectral images, a low complexity discrete cosine transform （DCT）-based distributed source coding （DSC） scheme with Gray code is proposed. Unlike most of the existing DSC schemes, which utilize transform in spatial domain, the proposed algorithm applies transform in spectral domain. Set-partitioning-based approach is applied to reorganize DCT coefficients into waveletlike tree structure and extract the sign, refinement, and significance bitplanes. The extracted refinement bits are Gray encoded. Because of the dependency along the line dimension of hyperspectral images, low density paritycheck-（LDPC）-based Slepian-Wolf coder is adopted to implement the DSC strategy. Experimental results on airborne visible/infrared imaging spectrometer （AVIRIS） dataset show that the proposed paradigm achieves up to 6 dB improvement over DSC-based coders which apply transform in spatial domain, with significantly reduced computational complexity and memory storage.
基金This work is supported in part by the Jiangsu Basic Research Programs-Natural Science Foundation under Grant No.BK20181407in part by the National Natural Science Foundation of China under Grant Nos.U1936118,61672294+4 种基金in part by Six Peak Talent Project of Jiangsu Province(R2016L13)Qinglan Project of Jiangsu Province,and“333”Project of Jiangsu Province,in part by the National Natural Science Foundation of China under Grant Nos.U1836208,61702276,61772283,61602253,and 61601236in part by National Key R&D Program of China under Grant No.2018YFB1003205in part by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)Fundin part by the Collaborative Innovation Center of Atmospheric Environment and Equipment Technology(CICAEET)Fund,China.Zhihua Xia is supported by BK21+Program from the Ministry of Education of Korea.
文摘As the wide application of imaging technology,the number of big image data which may containing private information is growing fast.Due to insufficient computing power and storage space for local server device,many people hand over these images to cloud servers for management.But actually,it is unsafe to store the images to the cloud,so encryption becomes a necessary step before uploading to reduce the risk of privacy leakage.However,it is not conducive to the efficient application of image,especially in the Content-Based Image Retrieval(CBIR)scheme.This paper proposes an outsourcing privacy-preserving JPEG CBIR scheme.We design a set of JPEG format-compatible encryption method,making no file expansion to JPEG files.We firstly combine multiple adjacent 8×8 DCT coefficient blocks into big-blocks.Then,random scrambling and stream encryption are used on the binary code of DCT coefficients to protect the JPEG image privacy.The task of extracting features from encrypted images and retrieving similar images are done by the cloud server.The group index histograms of DCT coefficients are extracted from the encrypted big-blocks,then the global vector is produced to represent the JPEG image with the aid of bag-of-words(BOW)model.The security analysis and experimental results show that our proposed scheme has strong security and good retrieval performance.
文摘The JPEG2000 image compression standard is the powerful encoder which can provide phenomenal rate-control performance.The post-compression rate-distortion(PCRD)algorithm in JPEG2000 is not efficient.It requires encoding all coding passes even though a large contribution of them will not be contained in the final code-stream.Tier-1 encoding in the JPEG2000 standard takes a significant amount of memory and coding time.In this work,a low-complexity rate distortion method for JPEG2000 is proposed.It is relied on a reverse order for the resolution levels and the coding passes.The proposed algorithm encodes only the coding passes contained in the final code-stream and it does not need any post compression rate control part.The computational complexity of proposed algorithm is negligible,making it suitable to compression and attaining a significant performance.Simulations results show that the proposed algorithm obtained the PSNR values are comparable with the optimal PCRD.
基金Electronic Development Fund of Ministry ofInformation Industry of China(No[2004]479)
文摘Based on the ideas of controlling relative quality and rearranging bitplanes, a new ROI coding method for JPEG2000 was proposed, which shifts and rearranges bitplanes in units of bitplane groups. It can code arbitrary shaped ROI without shape coding, and reserve almost arbitrary percent of background information. It also can control the relative quality of progressive decoded images. In addition, it is easy to be implemented and has low computational cost.
文摘In this paper, error-correction coding (ECC) in Gray codes is considered and its performance in the protecting of spatial image watermarks against lossy data compression is demonstrated. For this purpose, the differences between bit patterns of two Gray codewords are analyzed in detail. On the basis of the properties, a method for encoding watermark bits in the Gray codewords that represent signal levels by a single-error-correcting (SEC) code is developed, which is referred to as the Gray-ECC method in this paper. The two codewords of the SEC code corresponding to respective watermark bits are determined so as to minimize the expected amount of distortion caused by the watermark embedding. The stochastic analyses show that an error-correcting capacity of the Gray-ECC method is superior to that of the ECC in natural binary codes for changes in signal codewords. Experiments of the Gray-ECC method were conducted on 8-bit monochrome images to evaluate both the features of watermarked images and the performance of robustness for image distortion resulting from the JPEG DCT-baseline coding scheme. The results demonstrate that, compared with a conventional averaging-based method, the Gray-ECC method yields watermarked images with less amount of signal distortion and also makes the watermark comparably robust for lossy data compression.
