def compute_iou(rec1, rec2): """ computing IoU :param rec1: (y0, x0, y1, x1), which reflects (top, left, bottom, right) :param rec2: (y0, x0, y1, x1) :return: scala value of IoU """ # computing area of each rectangles S_rec1 = (rec1[2] - rec1[0]) * (rec1[3] - rec1[1]) S_rec2 = (rec2[2] - rec2[0]) * (rec2[3] - rec2[1]) # computing the sum_area sum_area = S_rec1 + S_rec2 # find the each edge of intersect rectangle left_line = max(rec1[1], rec2[1]) right_line = min(rec1[3], rec2[3]) top_line = max(rec1[0], rec2[0]) bottom_line = min(rec1[2], rec2[2]) # judge if there is an intersect if left_line >= right_line or top_line >= bottom_line: return 0 else: intersect = (right_line - left_line) * (bottom_line - top_line) return (intersect / (sum_area - intersect)) * 1.0 def compute_iou2(rec1, rec2): areas1 = (rec1[3] - rec1[1]) * (rec1[2] - rec1[0]) areas2 = (rec2[3] - rec2[1]) * (rec2[2] - rec2[0]) left = max(rec1[1],rec2[1]) right = min(rec1[3],rec2[3]) top = max(rec1[0], rec2[0]) bottom = min(rec1[2], rec2[2]) w = max(0, right-left) h = max(0, bottom-top) return w*h/(areas2+areas1-w*h) if __name__ == \'__main__\': rect1 = [661, 27, 679, 47] # (top, left, bottom, right) rect2 = [662, 27, 682, 47] iou = compute_iou(rect1, rect2) print(iou) print(compute_iou2(rect1, rect2))