利用短距強固主成分分析方法從光學同調斷層掃描資料擷取血管

Blood Vessel Extraction from Full-Field OCT Data of Human Skin by Short-Time RPCA

李品賢(Pin-Hsien Lee)

指導教授 ： 陳宏銘

國立臺灣大學/電機資訊學院/電信工程學研究所/碩士(2017年)

https://doi.org/10.6342/NTU201701397

摘要

光學同調斷層掃描(optical coherence tomography, OCT)的血管造影術能為診斷人體皮膚疾病提供有用資訊。我們在此論文中使用強固主成分分析(robust principal component analysis, RPCA)技術偵測全域式(full-field) OCT影像下的人體皮膚微血管。此外，為了對抗該類影像中的背景變化，我們提出短距強固主成分分析方法(short-time RPCA)。此方法將一全域式OCT影像作短距分割，從每個分割中找出流動的紅血球，最後將各分割的結果組合成血管影像。實驗結果證明我們的方法比其他方法有更佳的準確率，在影像成像品質較差的情況下也能夠擷取出血管。最後，我們也嘗試將短時距的概念套用至其他物體偵測方式，並證明其對偵測血管有所幫助。

關鍵字

強固主成分分析 ； 光學同調斷層掃描 ； 皮膚血管偵測

並列摘要

Recent advances in optical coherence tomography (OCT) lead to the development of OCT angiography to provide additional helpful information for diagnosis of diseases like basal cell carcinoma. In this thesis, we investigate how to extract blood vessels of human skin from full-field OCT data using the robust principal component analysis (RPCA) technique. Specifically, we propose a short-time RPCA method that divides the full-field OCT data into segments and decomposes each segment into a low-rank structure representing the relatively static tissues of human skin and a sparse matrix representing the blood vessels. The method mitigates the problem associated with the slow varying background and is free of the detection error that RPCA may have when dealing with FF-OCT data. We evaluate the performance of the proposed method by comparing the extracted blood vessels with the ground truth vessels labeled by dermatologist and show that the proposed method works equally well for FF-OCT volumes of different quality. The average accuracy improvements over the correlation-mapping OCT method and the amplitude-decorrelation OCT angiography method, respectively, are 18.35% and 10.32%. We also show that the idea of short-time analysis behind the proposed method can also be applied to improve the performance of DECOLOR, a related technique for foreground object detection.

並列關鍵字

robust principal component analysis ； optical coherence tomography ； blood vessel detection ； human skin

參考文獻

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