IET Image Process.最新文献_第8页

Multi-direction search algorithm for block motion estimation in H.264/AVC H.264/AVC中块运动估计的多方向搜索算法

IET Image Process. Pub Date : 2009-03-21 DOI: 10.1049/IET-IPR.2008.0042

C. C. Lin, Y. Lin, H. Hsieh

{"title":"Multi-direction search algorithm for block motion estimation in H.264/AVC","authors":"C. C. Lin, Y. Lin, H. Hsieh","doi":"10.1049/IET-IPR.2008.0042","DOIUrl":"https://doi.org/10.1049/IET-IPR.2008.0042","url":null,"abstract":"Many efficient search algorithms such as three-step search, new three-step search, four-step search, block-based gradient descent search, diamond search and hexagon-based search are developed for block motion estimation (ME) to search for the optimal objective function. The block ME technique involves an optimisation problem. Although these algorithms can converge to a minimal point rapidly, they suffer from becoming trapped in local minimum if the objective function has multiple minima. To solve this problem, the hybrid multi-hexagon-grid search (UMHexagonS) algorithm has been proposed in H.264/AVC, in which an unsymmetrical-cross search and an uneven UMHexagonS are employed over a wide search range to find a nearly global minimum. The experiment shows that the hybrid UMHexagonS algorithm is computation expensive and is occasionally trapped in local minimum. The authors propose a novel and fast search algorithm, called multi-direction search (MDS) algorithm, which uses an MDS first to find all possible locally optimal points and then uses the extended hexagon search to refine these points for the final optimal motion vector. The experimental results indicate that a significant improvement in computation reduction (∼30 and 50% reduction in average search points, corresponding to 19 and 37% reduction in total encoding time, for MDS and fast MDS, respectively) can be achieved while maintaining better coding performance, compared with the hybrid UMHexagonS algorithm.","PeriodicalId":13486,"journal":{"name":"IET Image Process.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2009-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79966080","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}

引用次数: 19

Histogram-based reversible data hiding for vector quantisation-compressed images 基于直方图的矢量量化压缩图像可逆数据隐藏

IET Image Process. Pub Date : 2009-03-21 DOI: 10.1049/IET-IPR.2007.0220

P. Tsai

引用次数: 69

Adaptive rate control for Motion JPEG2000 运动JPEG2000的自适应速率控制

IET Image Process. Pub Date : 2009-03-21 DOI: 10.1049/IET-IPR.2008.0053

Ling X. Li, Meng-Xin Guo, Zhensong Wang

{"title":"Adaptive rate control for Motion JPEG2000","authors":"Ling X. Li, Meng-Xin Guo, Zhensong Wang","doi":"10.1049/IET-IPR.2008.0053","DOIUrl":"https://doi.org/10.1049/IET-IPR.2008.0053","url":null,"abstract":"Rate and quality-constrained rate control is very effective for video applications, since it can maintain constant quality while eliminating local rate spikes. An adaptive rate control method based on image activity measures (ARCIAM) is proposed for Motion JPEG2000. The algorithm can efficiently adjust the compressed bit rates to meet the rate and quality constraints for different types of colour sequences. It predicts the rate-distortion (RD) slope thresholds for frames based on image activity measure (IAM) before entropy coding. Thus, the encoding of unnecessary coding passes can be avoided. Experimental results show that the proposed method can meet the quality and rate constraints, and can achieve quality performance comparable to post-compression rate distortion optimisation at the same bit rate. Under 3 bpp and 40 dB constraints, ARCIAM can reduce the total encoding time and tier-1 encoding time for sequences by more than 20 and 30 , respectively. Moreover, the memory requirement for buffering bit-streams and RD-slope information is reduced by more than 30 on average. Besides, the method can be incorporated into the line-based JPEG2000 encoding system easily, and has been implemented on Kakadu.","PeriodicalId":13486,"journal":{"name":"IET Image Process.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2009-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76889947","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}

引用次数: 4

Contrast enhancement and phase-sensitive boundary detection in ultrasonic speckle using Bessel spatial filters 基于贝塞尔空间滤波器的超声散斑对比度增强和相敏边界检测

IET Image Process. Pub Date : 2009-03-21 DOI: 10.1049/IET-IPR.2008.0045

P. Shankar

{"title":"Contrast enhancement and phase-sensitive boundary detection in ultrasonic speckle using Bessel spatial filters","authors":"P. Shankar","doi":"10.1049/IET-IPR.2008.0045","DOIUrl":"https://doi.org/10.1049/IET-IPR.2008.0045","url":null,"abstract":"Speckle in ultrasonic image systems adversely impacts the contrast and resolution in the image. This poses serious problems in the interpretation of B mode images of internal organs such as breast, liver, kidney and so on. In the absence of sufficient contrast, classifying the regions of interest into benign and malignant masses becomes error prone. Since some of the masses are uniquely identified in terms of the boundaries, poor contrast and resolution will result in difficulties with their identification. A new class of spatial filters based on cylindrical Bessel functions of the first kind is proposed for speckle reduction. These filters with complex impulse responses were explored for enhancing the contrast of speckled images. Hypothesising that the phase of the filtered image carries boundary information, the phase characteristics of four speckled images are also studied for detecting boundaries. Results indicate that these filters do improve the contrast and enhance the boundaries. It is shown that the phase map clearly indicates the existence of boundaries. A simple thresholding applied to the phase highlights the boundaries. The results show the strength of the Bessel spatial filters in improving contrast and highlighting boundaries without resorting to any additional edge-detection algorithms.","PeriodicalId":13486,"journal":{"name":"IET Image Process.","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2009-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79299058","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}

引用次数: 7

Rate control algorithm based on intra-picture complexity for H.264/AVC 基于H.264/AVC帧内复杂度的速率控制算法

IET Image Process. Pub Date : 2009-02-03 DOI: 10.1049/IET-IPR:20080088

G. Lee, Hongfei Lin, M.-J. Wang

引用次数: 11

Probabilistic relevance feedback approach for content-based image retrieval based on gaussian mixture models 基于高斯混合模型的基于内容的图像检索的概率相关反馈方法

IET Image Process. Pub Date : 2009-02-03 DOI: 10.1049/IET-IPR:20080012

Apostolos Marakakis, N. Galatsanos, A. Likas, A. Stafylopatis

引用次数: 14