처리속도 개선을 위한 공간적 중복성 제거 기반 실시간 스테레오 매칭 알고리즘

학위논문(석사) - 한국과학기술원 : 정보통신공학과, 2010.08, [ vii, 47 p. ]Stereo Matching has been one of the most active research topics in the area of computer vision. Many research works in this field have focused on either improving the accuracy of a resulting disparity map or reducing the processing time in a separate manner. However, there has been relatively little research effort in order to reduce computational complexity or processing time, while improving the accuracy of disparity estimation at the same time. In this thesis, a time efficient approach for real-time stereo matching is proposed. To this end, Dynamic Programming (DP), a popular global energy optimization algorithm, has been chosen to be a framework where the proposed approach is applied, since the DP is able to meet real-time requirements even in a computation-limited environment and thus implies its broad applicability. From extensive experiments, we show that the proposed method can significantly reduce the processing time to the extent that real-time implementation of disparity map estimation can be realized. In addition, a novel modified adaptive support-weight filter that is designed to guarantee reliable estimation of disparity map has also been successfully evaluated in comparison with conventional filters in our experiments. In conclusion, as opposed to most previous works with emphasis on hardware level optimization for the processing time reduction, the proposed approach can provide a time efficient method which is employed at an algorithm level. Further, it can preserve the reliable estimation accuracy by successfully addressing the errors (little increased by the proposed preprocessing time reduction) and even improve the overall estimation accuracy in a resulting disparity map.한국과학기술원 : 정보통신공학과

Evaluation of deep learning-based autosegmentation in breast cancer radiotherapy

Purpose To study the performance of a proposed deep learning-based autocontouring system in delineating organs at risk (OARs) in breast radiotherapy with a group of experts. Methods Eleven experts from two institutions delineated nine OARs in 10 cases of adjuvant radiotherapy after breast-conserving surgery. Autocontours were then provided to the experts for correction. Overall, 110 manual contours, 110 corrected autocontours, and 10 autocontours of each type of OAR were analyzed. The Dice similarity coefficient (DSC) and Hausdorff distance (HD) were used to compare the degree of agreement between the best manual contour (chosen by an independent expert committee) and each autocontour, corrected autocontour, and manual contour. Higher DSCs and lower HDs indicated a better geometric overlap. The amount of time reduction using the autocontouring system was examined. User satisfaction was evaluated using a survey. Results Manual contours, corrected autocontours, and autocontours had a similar accuracy in the average DSC value (0.88 vs. 0.90 vs. 0.90). The accuracy of autocontours ranked the second place, based on DSCs, and the first place, based on HDs among the manual contours. Interphysician variations among the experts were reduced in corrected autocontours, compared to variations in manual contours (DSC: 0.89-0.90 vs. 0.87-0.90; HD: 4.3-5.8 mm vs. 5.3-7.6 mm). Among the manual delineations, the breast contours had the largest variations, which improved most significantly with the autocontouring system. The total mean times for nine OARs were 37 min for manual contours and 6 min for corrected autocontours. The results of the survey revealed good user satisfaction. Conclusions The autocontouring system had a similar performance in OARs as that of the experts' manual contouring. This system can be valuable in improving the quality of breast radiotherapy and reducing interphysician variability in clinical practice

Comparative Analyses of Inflammatory Response and Tissue Integration of 14 Hyaluronic Acid-Based Fillers in Mini Pigs

Purpose: Hyaluronic acid (HA)-based dermal fillers have been approved for various clinical indications, both cosmetic and medical. Previous studies that have assessed the performance of HA dermal fillers have primarily focused on evaluating filler durability, and only a few have studied their distribution within the tissues. The present study aimed to compare tissue integration of various types of HA dermal fillers having different clinical indications and varying injection depths. Methods: To examine the local inflammatory response and distribution pattern of 14 HA dermal fillers (six Neuramis [NEU], one Belotero [BEL], three Juv eacute;derm [JUV], and four Restylane [RES]), each product was injected intradermally and subcutaneously at the backs of two male miniature pigs. Histopathological evaluation and visual examination of the tissue sections were conducted 1 and 4 weeks after injection. Results: Mean inflammatory cell infiltration scores tended to be lower in response to fillers from the NEU and BEL series than to those from the JUV and RES series after intradermal and subcutaneous injection. Furthermore, the inflammatory response to fillers with higher physicochemical properties specifically designed for injection into deeper layers of the skin tended to be slightly higher than those designated for injection into more superficial layers. There was no significant difference in tissue integration according to clinical indication and injection depth, although fillers from the NEU and BEL series exhibited better tissue integration than those from the JUV and RES series . Conclusion: Our findings not only suggest that the local inflammatory response and tissue integration differ across HA dermal filler products, but also that these parameters could vary according to the recommended clinical indication and injection depth of the products