| import numpy as np | |
| def bbox_overlaps(bboxes1, bboxes2, mode='iou', eps=1e-6): | |
| """Calculate the ious between each bbox of bboxes1 and bboxes2. | |
| Args: | |
| bboxes1(ndarray): shape (n, 4) | |
| bboxes2(ndarray): shape (k, 4) | |
| mode(str): iou (intersection over union) or iof (intersection | |
| over foreground) | |
| Returns: | |
| ious(ndarray): shape (n, k) | |
| """ | |
| assert mode in ['iou', 'iof'] | |
| bboxes1 = bboxes1.astype(np.float32) | |
| bboxes2 = bboxes2.astype(np.float32) | |
| rows = bboxes1.shape[0] | |
| cols = bboxes2.shape[0] | |
| ious = np.zeros((rows, cols), dtype=np.float32) | |
| if rows * cols == 0: | |
| return ious | |
| exchange = False | |
| if bboxes1.shape[0] > bboxes2.shape[0]: | |
| bboxes1, bboxes2 = bboxes2, bboxes1 | |
| ious = np.zeros((cols, rows), dtype=np.float32) | |
| exchange = True | |
| area1 = (bboxes1[:, 2] - bboxes1[:, 0]) * (bboxes1[:, 3] - bboxes1[:, 1]) | |
| area2 = (bboxes2[:, 2] - bboxes2[:, 0]) * (bboxes2[:, 3] - bboxes2[:, 1]) | |
| for i in range(bboxes1.shape[0]): | |
| x_start = np.maximum(bboxes1[i, 0], bboxes2[:, 0]) | |
| y_start = np.maximum(bboxes1[i, 1], bboxes2[:, 1]) | |
| x_end = np.minimum(bboxes1[i, 2], bboxes2[:, 2]) | |
| y_end = np.minimum(bboxes1[i, 3], bboxes2[:, 3]) | |
| overlap = np.maximum(x_end - x_start, 0) * np.maximum( | |
| y_end - y_start, 0) | |
| if mode == 'iou': | |
| union = area1[i] + area2 - overlap | |
| else: | |
| union = area1[i] if not exchange else area2 | |
| union = np.maximum(union, eps) | |
| ious[i, :] = overlap / union | |
| if exchange: | |
| ious = ious.T | |
| return ious | |