反應器內部組件目視檢測之數位影像分析

Abstract

目視檢測為非破壞檢測技術中的一個重要項目，其特點為較直接且迅速地從事前期檢測工作，在核反應器的應用方面，為了解反應器的健康狀況，需定時對反應器及其內部組件進行反應器內部組件目視檢測(In Vessel Visual Inspection, 簡稱IVVI)，由於爐內組件具有高幅射性，人員不易接近，故利用水底攝影機等光學輔助器材進行遠距目視檢測，所拍攝之水底攝影影像，雖利於檢測者於現場或事後從事判讀，但由於判讀影帶時難以和反應器真實位置整合，且影像本身有時因打光不勻或攝像系統的像差問題，判讀瑕疵之位置與尺寸不易，尤其在比較不同時間所攝得的特定瑕疵影像時，因拍攝角度與遠近不同，很難以目視判斷此特定瑕疵是否有增長情形(是否為active)，故需要一個影像量化分析的工具來協助。 近年來，隨著電腦科技的蓬勃發展，數位影像處理技術(Digital Image Processing)也廣用於各科學與工程領域，本研究之主要工作即為應用數位影像處理相關技術於反應器內部組件目視檢測 其重點工作項目為 (a)開發IVVI連續影像數位化永久保存技術。(b)應用虛擬實境技術整合IVVI影像與真實空間位置。(c)建立相機自我校正模式，標定不同時間拍攝影像中特定物件變化。(d)應用電腦視覺技術自動化量測攝像系統解析度。經由本研究案之進行，將能進一步確實掌握反應器的健康狀況，做為運轉之參考。

Visual Inspection is one of the non-destruction testing (NDT) and the features of visual inspection are direct and rapid. In it’s application to RPV and internals, the In-Vessel Visual Inspection (IVVI) is performed periodically to monitor the integrity of the reactor and internals. Due to the high radioactivity, the IVVI is performed remotely by an underwater camera imaging system. The trained inspector can use a monitor to watch the underwater reactor structures in real time or for post-analysis. However, the critical lighting condition and the distortion of the imaging system bring some difficulties in judging the defect’s size and whether the defect is active or not. We need a new tool to quantify the messages buried inside those IVVI images. In the recent years, the innovation of computer technology makes digital image analysis technique more accessible for engineers and scientist in varied research fields. We hope to apply the digital image processing to the IVVI application. The proposed works in this year include the following topics: (a) IVVI image digitization for permanent storage, (b) Virtual reality for the integration of IVVI images and real position, (c) Camera self-calibration for IVVI images from different image systems at different time, (d) Automatic measurement of the MTF (Modulation Transfer Function) of the imaging system by computer vision. In this research project, image analysis of IVVI images would be beneficial to normal operation of the nuclear reactor.