Recognizing reference points for photogrammetry of traffic accident scene
交通事故现场摄影测量标定点识别

The recognization of reference points is important to survey traffic accident scene fleetly using photographs. In the nature light, there are shadows on the area of reference points. Infinite impulse response (IIR) filter was used to detect ridge edge and avoid the effect of shadows in nature light. After line was detected, reference line could be recognized and ordered based on clustering. Dynamic Clustering Analysis (DCA) was used to cluster lines. In order to robust result of clustering, DCA was improved: median value was used to replace mean value as the clustering center. Maximal and minimal distance analysis arithmetic was used to initialize clustering centers.