NaN may appear in the demo

[GallonDeng]

great repo. I ran some tests and found that NaN may appear in the code, speciffically, in the bbox calculation and iou function.

[GajuuzZ]

Where it NaN appeared and how did you get it?

[GallonDeng]

I just dowloaded a video from web and tested it with the repo. It ran a while and got stuck, showed warning invaild values in the code "cost_matrix[cost_matrix > max_distance] = max_distance + 1e-5" in the "min_cost_matching" function. I checked that NaN appeared in the "iou(bbox, candidates)" function in the iou_matching.py. Specifically, there may be invalid "bbox" and "candidates" which result in NaN.

[nobody-cheng]

I just dowloaded a video from web and tested it with the repo. It ran a while and got stuck, showed warning invaild values in the code "cost_matrix[cost_matrix > max_distance] = max_distance + 1e-5" in the "min_cost_matching" function. I checked that NaN appeared in the "iou(bbox, candidates)" function in the iou_matching.py. Specifically, there may be invalid "bbox" and "candidates" which result in NaN.

fix bug？？