Pub Date : 2009-10-09DOI: 10.1049/IET-IPR.2008.0155
Chen-Chang Wu, Ye-In Chang
Space-filling curves, particularly, Hilbert curves, have been extensively used to maintain spatial locality of multi-dimensional data in a wide variety of applications. A window query is an important query operation in spatial (image) databases. Given a Hilbert curve, a window query reports its corresponding orders without the need to decode all the points inside this window into the corresponding Hilbert orders. Given a query window of size p times q on a Hilbert curve of size T times T , Chung et al. have proposed an algorithm for decomposing a window into the corresponding Hilbert orders, which needs O ( n log T ) time, where n = max ( p , q ). By employing the properties of Hilbert curves, the authors present an efficient algorithm, named as Quad-Splitting, for decomposing a window into the corresponding Hilbert orders on a Hilbert curve without individual sorting and merging steps. Although the proposed algorithm also takes O ( n log T ) time, it does not perform individual sorting and merging steps which are needed in Chung et al. 's algorithm. Therefore experimental results show that the Quad-Splitting algorithm outperforms Chung et al. 's algorithm.
{"title":"Quad-splitting algorithm for a window query on a Hilbert curve","authors":"Chen-Chang Wu, Ye-In Chang","doi":"10.1049/IET-IPR.2008.0155","DOIUrl":"https://doi.org/10.1049/IET-IPR.2008.0155","url":null,"abstract":"Space-filling curves, particularly, Hilbert curves, have been extensively used to maintain spatial locality of multi-dimensional data in a wide variety of applications. A window query is an important query operation in spatial (image) databases. Given a Hilbert curve, a window query reports its corresponding orders without the need to decode all the points inside this window into the corresponding Hilbert orders. Given a query window of size p times q on a Hilbert curve of size T times T , Chung et al. have proposed an algorithm for decomposing a window into the corresponding Hilbert orders, which needs O ( n log T ) time, where n = max ( p , q ). By employing the properties of Hilbert curves, the authors present an efficient algorithm, named as Quad-Splitting, for decomposing a window into the corresponding Hilbert orders on a Hilbert curve without individual sorting and merging steps. Although the proposed algorithm also takes O ( n log T ) time, it does not perform individual sorting and merging steps which are needed in Chung et al. 's algorithm. Therefore experimental results show that the Quad-Splitting algorithm outperforms Chung et al. 's algorithm.","PeriodicalId":13486,"journal":{"name":"IET Image Process.","volume":"17 1","pages":"299-311"},"PeriodicalIF":0.0,"publicationDate":"2009-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81327273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-10-09DOI: 10.1049/IET-IPR.2008.0093
C. Mak, W. Cham
In this study the authors proposed a real-time video object segmentation algorithm that works in the H.264 compressed domain. The algorithm utilises the motion information from the H.264 compressed bit stream to identify background motion model and moving objects. In order to preserve spatial and temporal continuity of objects, Markov random field (MRF) is used to model the foreground field. Quantised transform coefficients of the residual frame are also used to improve segmentation result. Experimental results show that the proposed algorithm can effectively extract moving objects from different kinds of sequences. The computation time of the segmentation process is merely about 16 ms per frame for CIF size frame, allowing the algorithm to be applied in real-time applications.
{"title":"Real-time video object segmentation in H.264 compressed domain","authors":"C. Mak, W. Cham","doi":"10.1049/IET-IPR.2008.0093","DOIUrl":"https://doi.org/10.1049/IET-IPR.2008.0093","url":null,"abstract":"In this study the authors proposed a real-time video object segmentation algorithm that works in the H.264 compressed domain. The algorithm utilises the motion information from the H.264 compressed bit stream to identify background motion model and moving objects. In order to preserve spatial and temporal continuity of objects, Markov random field (MRF) is used to model the foreground field. Quantised transform coefficients of the residual frame are also used to improve segmentation result. Experimental results show that the proposed algorithm can effectively extract moving objects from different kinds of sequences. The computation time of the segmentation process is merely about 16 ms per frame for CIF size frame, allowing the algorithm to be applied in real-time applications.","PeriodicalId":13486,"journal":{"name":"IET Image Process.","volume":"409 1","pages":"272-285"},"PeriodicalIF":0.0,"publicationDate":"2009-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76493388","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-10-09DOI: 10.1049/IET-IPR.2008.0192
Yashen Lin, Yi Chun Wang
In this study, the authors propose an efficient fractional pixel search algorithm for H.264/AVC video coding to reduce the computational complexity in half/quarter-pixel motion estimation. A prediction for the optimal motion vector is derived under the assumption that the sum of absolute transform differences error surface is a symmetric parabolic function. With the optimal region, a decision rule for half-pixel search is proposed. The experimental result shows that approximately two search points are required. Based on the half-pixel search, a hierarchical quarter-pixel search is described and an extra three search points, on average, are consumed for each quarter-pixel search. Experimental results show that significant reduction in computation can be achieved, while maintaining high coding efficiency.
{"title":"Improved parabolic prediction-based fractional search for H.264/AVC video coding","authors":"Yashen Lin, Yi Chun Wang","doi":"10.1049/IET-IPR.2008.0192","DOIUrl":"https://doi.org/10.1049/IET-IPR.2008.0192","url":null,"abstract":"In this study, the authors propose an efficient fractional pixel search algorithm for H.264/AVC video coding to reduce the computational complexity in half/quarter-pixel motion estimation. A prediction for the optimal motion vector is derived under the assumption that the sum of absolute transform differences error surface is a symmetric parabolic function. With the optimal region, a decision rule for half-pixel search is proposed. The experimental result shows that approximately two search points are required. Based on the half-pixel search, a hierarchical quarter-pixel search is described and an extra three search points, on average, are consumed for each quarter-pixel search. Experimental results show that significant reduction in computation can be achieved, while maintaining high coding efficiency.","PeriodicalId":13486,"journal":{"name":"IET Image Process.","volume":"105 1","pages":"261-271"},"PeriodicalIF":0.0,"publicationDate":"2009-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77627462","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-10-01DOI: 10.1049/IET-IPR.2009.0037
Y. Sun, Yimin Zhou, Zhidan Feng, Zhihai He, Shixin Sun
In this study, the authors propose a new rate-complexity-quantisation model and an incremental rate control algorithm for H.264/AVC video coding. One unique property of this algorithm is that, the picture complexity estimation and rate-quantisation modelling are jointly designed with an incremental rate control for P-frames. In addition, the proposed algorithm also introduces a number of efficient rate control techniques, including accurate rate control for intra-frames, enhanced proportional–integral–derivative (PID) buffer controller, and adaptive quantisation parameter determination for B-frames. The proposed algorithm has low computational complexity while providing robust rate control. Our extensive experimental results demonstrate that the proposed algorithm outperforms the current rate control algorithm adopted in the H.264/AVC reference software JM13.2 by achieving more accurate rate control, reducing frame skipping, depressing quality fluctuation and improving the overall coding quality by up to 2.83 dB.
{"title":"Incremental rate control for H.264/AVC video compression","authors":"Y. Sun, Yimin Zhou, Zhidan Feng, Zhihai He, Shixin Sun","doi":"10.1049/IET-IPR.2009.0037","DOIUrl":"https://doi.org/10.1049/IET-IPR.2009.0037","url":null,"abstract":"In this study, the authors propose a new rate-complexity-quantisation model and an incremental rate control algorithm for H.264/AVC video coding. One unique property of this algorithm is that, the picture complexity estimation and rate-quantisation modelling are jointly designed with an incremental rate control for P-frames. In addition, the proposed algorithm also introduces a number of efficient rate control techniques, including accurate rate control for intra-frames, enhanced proportional–integral–derivative (PID) buffer controller, and adaptive quantisation parameter determination for B-frames. The proposed algorithm has low computational complexity while providing robust rate control. Our extensive experimental results demonstrate that the proposed algorithm outperforms the current rate control algorithm adopted in the H.264/AVC reference software JM13.2 by achieving more accurate rate control, reducing frame skipping, depressing quality fluctuation and improving the overall coding quality by up to 2.83 dB.","PeriodicalId":13486,"journal":{"name":"IET Image Process.","volume":"460 1","pages":"286-298"},"PeriodicalIF":0.0,"publicationDate":"2009-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75832930","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-10-01DOI: 10.1049/iet-ipr.2009.0056
M. E. Celebi
Reduced ordering-based vector filters have proved successful in removing long-tailed noise from colour images while preserving edges and fine image details. These filters commonly utilise variants of the Minkowski distance to order the colour vectors with the aim of distinguishing between noisy and noise-free vectors. In this study, the authors review various alternative distance measures and evaluate their performance on a large and diverse set of images using several effectiveness and efficiency criteria. The results demonstrate that there are in fact strong alternatives to the popular Minkowski metrics.
{"title":"Distance Measures for Reduced Ordering Based Vector Filters","authors":"M. E. Celebi","doi":"10.1049/iet-ipr.2009.0056","DOIUrl":"https://doi.org/10.1049/iet-ipr.2009.0056","url":null,"abstract":"Reduced ordering-based vector filters have proved successful in removing long-tailed noise from colour images while preserving edges and fine image details. These filters commonly utilise variants of the Minkowski distance to order the colour vectors with the aim of distinguishing between noisy and noise-free vectors. In this study, the authors review various alternative distance measures and evaluate their performance on a large and diverse set of images using several effectiveness and efficiency criteria. The results demonstrate that there are in fact strong alternatives to the popular Minkowski metrics.","PeriodicalId":13486,"journal":{"name":"IET Image Process.","volume":"7 1","pages":"249-260"},"PeriodicalIF":0.0,"publicationDate":"2009-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84882076","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-09-04DOI: 10.1049/IET-IPR.2008.0251
Cheng-Chi Lee, W.-H. Ku, Shiow-Yuan Huang
In this paper, the authors propose a new steganographic scheme based on vector quantisation (VQ) and search-order coding (SOC). The capacity of the proposed scheme is higher than others based on VQ and the quality of stego-image is acceptive. In general, the capacity of the schemes based on VQ is usually 1-bit per block. In 2004, Yu et al. proposed a scheme to increase the capacity to 3-bit per pair of blocks. In the proposed scheme, the authors utilised multiple codebooks and chose the combinations of per pair of blocks, to embed the secret data. The capacity was increased to 6-bit per pair of blocks, and the quality was identical Yu et al.'s scheme.
{"title":"A new steganographic scheme based on vector quantisation and search-order coding","authors":"Cheng-Chi Lee, W.-H. Ku, Shiow-Yuan Huang","doi":"10.1049/IET-IPR.2008.0251","DOIUrl":"https://doi.org/10.1049/IET-IPR.2008.0251","url":null,"abstract":"In this paper, the authors propose a new steganographic scheme based on vector quantisation (VQ) and search-order coding (SOC). The capacity of the proposed scheme is higher than others based on VQ and the quality of stego-image is acceptive. In general, the capacity of the schemes based on VQ is usually 1-bit per block. In 2004, Yu et al. proposed a scheme to increase the capacity to 3-bit per pair of blocks. In the proposed scheme, the authors utilised multiple codebooks and chose the combinations of per pair of blocks, to embed the secret data. The capacity was increased to 6-bit per pair of blocks, and the quality was identical Yu et al.'s scheme.","PeriodicalId":13486,"journal":{"name":"IET Image Process.","volume":"20 1","pages":"243-248"},"PeriodicalIF":0.0,"publicationDate":"2009-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82317271","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-09-04DOI: 10.1049/IET-IPR.2008.0213
Chih-Ling Hsu, Chang-Hsin Cheng
This study develops a novel prediction algorithm to effectively save the computational complexity of discrete cosine transform (DCT), quantisation (Q), inverse Q (IQ), and inverse DCT (IDCT) in video encoding for H.264 applications. Based on the DC value of the DCT coefficients that is equal to the sum of residual data in the 4×4 sub-macroblock (sub-MB), a mathematical model is built to develop a prediction algorithm for reducing the computations in the DCT/Q/IQ/IDCT process. Experimental results and comparisons demonstrate that the proposed prediction algorithm significantly reduces the encoding time while incurring little additional overhead, and lowers the bit rate with little peak signal-to-noise ratio degradation.
{"title":"Reduction of discrete cosine transform/quantisation/inverse quantisation/inverse discrete cosine transform computational complexity in H.264 video encoding by using an efficient prediction algorithm","authors":"Chih-Ling Hsu, Chang-Hsin Cheng","doi":"10.1049/IET-IPR.2008.0213","DOIUrl":"https://doi.org/10.1049/IET-IPR.2008.0213","url":null,"abstract":"This study develops a novel prediction algorithm to effectively save the computational complexity of discrete cosine transform (DCT), quantisation (Q), inverse Q (IQ), and inverse DCT (IDCT) in video encoding for H.264 applications. Based on the DC value of the DCT coefficients that is equal to the sum of residual data in the 4×4 sub-macroblock (sub-MB), a mathematical model is built to develop a prediction algorithm for reducing the computations in the DCT/Q/IQ/IDCT process. Experimental results and comparisons demonstrate that the proposed prediction algorithm significantly reduces the encoding time while incurring little additional overhead, and lowers the bit rate with little peak signal-to-noise ratio degradation.","PeriodicalId":13486,"journal":{"name":"IET Image Process.","volume":"128 1","pages":"177-187"},"PeriodicalIF":0.0,"publicationDate":"2009-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73727430","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-09-04DOI: 10.1049/IET-IPR.2008.0044
C. J. Zhang, X. D. Wang
By employing discrete stationary wavelet transform (SWT), generalised cross-validation (GCV), genetic algorithm (GA), and non-linear gain operator, an efficient de-noising and enhancement algorithm for typhoon cloud image is proposed. Having implemented SWT to a typhoon cloud image, noise in a typhoon cloud image is reduced by modifying the stationary wavelet coefficients using GA and GCV at fine resolution levels. Asymptotical optimal de-noising threshold can be obtained, without knowing the variance of noise, by only employing the known input image data. GA and non-linear gain operator are used to modify the stationary wavelet coefficients at coarse resolution levels in order to enhance the details of a typhoon cloud image. Experimental results show that the proposed algorithm can efficiently reduce the speckle in a typhoon cloud image while well enhancing the detail. In order to accurately assess an enhanced typhoon cloud image's quality, an overall score index is proposed based on information entropy, contrast measure and peak signal-noise-ratio (PSNR). Finally, comparisons between the proposed algorithm and other similar methods, which are proposed based on discrete wavelet transform, are carried out.
{"title":"Typhoon cloud image enhancement and reducing speckle with genetic algorithm in stationary wavelet domain","authors":"C. J. Zhang, X. D. Wang","doi":"10.1049/IET-IPR.2008.0044","DOIUrl":"https://doi.org/10.1049/IET-IPR.2008.0044","url":null,"abstract":"By employing discrete stationary wavelet transform (SWT), generalised cross-validation (GCV), genetic algorithm (GA), and non-linear gain operator, an efficient de-noising and enhancement algorithm for typhoon cloud image is proposed. Having implemented SWT to a typhoon cloud image, noise in a typhoon cloud image is reduced by modifying the stationary wavelet coefficients using GA and GCV at fine resolution levels. Asymptotical optimal de-noising threshold can be obtained, without knowing the variance of noise, by only employing the known input image data. GA and non-linear gain operator are used to modify the stationary wavelet coefficients at coarse resolution levels in order to enhance the details of a typhoon cloud image. Experimental results show that the proposed algorithm can efficiently reduce the speckle in a typhoon cloud image while well enhancing the detail. In order to accurately assess an enhanced typhoon cloud image's quality, an overall score index is proposed based on information entropy, contrast measure and peak signal-noise-ratio (PSNR). Finally, comparisons between the proposed algorithm and other similar methods, which are proposed based on discrete wavelet transform, are carried out.","PeriodicalId":13486,"journal":{"name":"IET Image Process.","volume":"11 1","pages":"200-216"},"PeriodicalIF":0.0,"publicationDate":"2009-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78894025","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-08-01DOI: 10.1049/IET-IPR.2007.0195
Sangkeun Lee
A compressed image reproduction scheme is proposed by properly decomposing and manipulating the coefficients of discrete cosine transform (DCT) directly in the compressed domain. The basic idea of the proposed approach is to decompose each DCT block into several sub-blocks and to adjust the brightness and detail components of a given image for compressing dynamic range and enhancing contrast. Image reproduction based on the subblock decomposition can be done more precisely than any approach based on the normal block-sized approach. First, DCT coefficients of each block are decomposed into several sub-blocks. Next each sub-block's coefficients are separated into brightness and detail components, and treated differently according to content analysis. Then, the enhanced coefficients are projected on the constraint sets to avoid some artefacts, and are composed back to the original order. The main advantages of the proposed algorithm are that (i) it can enhance the dynamic range and details without affecting the compressibility of the given image since it operates directly in the compressed domain, and (ii) it does not boost blocking artefacts around big edges without any further processing. In order to evaluate the proposed scheme, several base-line approaches are described and compared using enhancement quality measures.
{"title":"Compressed image reproduction based on block decomposition","authors":"Sangkeun Lee","doi":"10.1049/IET-IPR.2007.0195","DOIUrl":"https://doi.org/10.1049/IET-IPR.2007.0195","url":null,"abstract":"A compressed image reproduction scheme is proposed by properly decomposing and manipulating the coefficients of discrete cosine transform (DCT) directly in the compressed domain. The basic idea of the proposed approach is to decompose each DCT block into several sub-blocks and to adjust the brightness and detail components of a given image for compressing dynamic range and enhancing contrast. Image reproduction based on the subblock decomposition can be done more precisely than any approach based on the normal block-sized approach. First, DCT coefficients of each block are decomposed into several sub-blocks. Next each sub-block's coefficients are separated into brightness and detail components, and treated differently according to content analysis. Then, the enhanced coefficients are projected on the constraint sets to avoid some artefacts, and are composed back to the original order. The main advantages of the proposed algorithm are that (i) it can enhance the dynamic range and details without affecting the compressibility of the given image since it operates directly in the compressed domain, and (ii) it does not boost blocking artefacts around big edges without any further processing. In order to evaluate the proposed scheme, several base-line approaches are described and compared using enhancement quality measures.","PeriodicalId":13486,"journal":{"name":"IET Image Process.","volume":"59 1","pages":"188-199"},"PeriodicalIF":0.0,"publicationDate":"2009-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74369789","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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