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| import numpy as np |
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| def py_cpu_nms(dets, thresh): |
| """Pure Python NMS baseline.""" |
| x1 = dets[:, 0] |
| y1 = dets[:, 1] |
| x2 = dets[:, 2] |
| y2 = dets[:, 3] |
| scores = dets[:, 4] |
|
|
| areas = (x2 - x1 + 1) * (y2 - y1 + 1) |
| order = scores.argsort()[::-1] |
|
|
| keep = [] |
| while order.size > 0: |
| i = order[0] |
| keep.append(i) |
| xx1 = np.maximum(x1[i], x1[order[1:]]) |
| yy1 = np.maximum(y1[i], y1[order[1:]]) |
| xx2 = np.minimum(x2[i], x2[order[1:]]) |
| yy2 = np.minimum(y2[i], y2[order[1:]]) |
|
|
| w = np.maximum(0.0, xx2 - xx1 + 1) |
| h = np.maximum(0.0, yy2 - yy1 + 1) |
| inter = w * h |
| ovr = inter / (areas[i] + areas[order[1:]] - inter) |
|
|
| inds = np.where(ovr <= thresh)[0] |
| order = order[inds + 1] |
|
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| return keep |
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|
