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Recent Advances in Signal Processing 2011 Part 4

Tham khảo tài liệu 'recent advances in signal processing 2011 part 4', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 92 Recent Advances in Signal Processing Fig. 5. Segmentation results and optical flow for the first five images of the sequence. The first column shows the CINE images with the segmentation and the second column shows the optical flow obtained with the tagged CMR images. As it can be seen the results obtained adjust well to the endocardium and epicardium. The contour fit perfectly to the myocardial border avoiding the inclusion of the papillary muscles which can not be achieved so easily on the tagged images. Fig. 6 shows the results of the computational time. As it can be seen in figure 6 the computational time for the integrated solution is smaller than the one needed if the sequence were segmented frame by frame. Fluctuations on the computational time for the integrated method are due only to the refinement of the segmentation needed for each frame this fact explains the increase of the computational time between frames forth and fifth. Combined myocardial motion estimation and segmentation using variational techniques 93 Computational Time Integration motionsegmentation Only segmentation Fig. 6. Computational time for the proposed integrated solution compared with the time obtained segmenting each image for the dual sequence. The results of the evaluation of the 46 curves tested are shown in Table 1. Resultant parameters show that the segmentation performance is very accurate. Mean Distance pixels Mean SD Hanssdorf Distance pixels Mean SD Overlapping degree i Mean SD Sequence 1 Endocardium 0.94 0.9 2.71 1.44 90 3.84 Epicardium 1.01 0.04 2.80 0.21 93 1.85 Sequence 2 Endocardium 1.25 0.16 3.75 0.97 88 4.04 Epicardium 0.96 0.00 2.65 0.40 94 0.59 Sequence 3 Endocardium 0.87 0.18 2.82 0.33 87 3.12 Epicardium 0.82 0.31 2.60 0.70 92 2.93 Sequence 4 Endocardium 0.88 0.43 2.35 1.09 90 6.01 Epicardium 1.24 0.22 3.54 0.74 90 1.62 Table 1. Evaluation results of the segmentation mean distance Haussdorf distance and overlapping degree for the four sequences tested in .