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# Copyright (c) Facebook, Inc. and its affiliates. | |
from __future__ import absolute_import, division, print_function, unicode_literals | |
import numpy as np | |
import unittest | |
from copy import deepcopy | |
import torch | |
from torchvision import ops | |
from detectron2.layers import batched_nms, batched_nms_rotated, nms_rotated | |
from detectron2.utils.testing import random_boxes | |
def nms_edit_distance(keep1, keep2): | |
""" | |
Compare the "keep" result of two nms call. | |
They are allowed to be different in terms of edit distance | |
due to floating point precision issues, e.g., | |
if a box happen to have an IoU of 0.5 with another box, | |
one implentation may choose to keep it while another may discard it. | |
""" | |
keep1, keep2 = keep1.cpu(), keep2.cpu() | |
if torch.equal(keep1, keep2): | |
# they should be equal most of the time | |
return 0 | |
keep1, keep2 = tuple(keep1), tuple(keep2) | |
m, n = len(keep1), len(keep2) | |
# edit distance with DP | |
f = [np.arange(n + 1), np.arange(n + 1)] | |
for i in range(m): | |
cur_row = i % 2 | |
other_row = (i + 1) % 2 | |
f[other_row][0] = i + 1 | |
for j in range(n): | |
f[other_row][j + 1] = ( | |
f[cur_row][j] | |
if keep1[i] == keep2[j] | |
else min(min(f[cur_row][j], f[cur_row][j + 1]), f[other_row][j]) + 1 | |
) | |
return f[m % 2][n] | |
class TestNMSRotated(unittest.TestCase): | |
def reference_horizontal_nms(self, boxes, scores, iou_threshold): | |
""" | |
Args: | |
box_scores (N, 5): boxes in corner-form and probabilities. | |
(Note here 5 == 4 + 1, i.e., 4-dim horizontal box + 1-dim prob) | |
iou_threshold: intersection over union threshold. | |
Returns: | |
picked: a list of indexes of the kept boxes | |
""" | |
picked = [] | |
_, indexes = scores.sort(descending=True) | |
while len(indexes) > 0: | |
current = indexes[0] | |
picked.append(current.item()) | |
if len(indexes) == 1: | |
break | |
current_box = boxes[current, :] | |
indexes = indexes[1:] | |
rest_boxes = boxes[indexes, :] | |
iou = ops.box_iou(rest_boxes, current_box.unsqueeze(0)).squeeze(1) | |
indexes = indexes[iou <= iou_threshold] | |
return torch.as_tensor(picked) | |
def _create_tensors(self, N, device="cpu"): | |
boxes = random_boxes(N, 200, device=device) | |
scores = torch.rand(N, device=device) | |
return boxes, scores | |
def test_batched_nms_rotated_0_degree_cpu(self, device="cpu"): | |
N = 2000 | |
num_classes = 50 | |
boxes, scores = self._create_tensors(N, device=device) | |
idxs = torch.randint(0, num_classes, (N,)) | |
rotated_boxes = torch.zeros(N, 5, device=device) | |
rotated_boxes[:, 0] = (boxes[:, 0] + boxes[:, 2]) / 2.0 | |
rotated_boxes[:, 1] = (boxes[:, 1] + boxes[:, 3]) / 2.0 | |
rotated_boxes[:, 2] = boxes[:, 2] - boxes[:, 0] | |
rotated_boxes[:, 3] = boxes[:, 3] - boxes[:, 1] | |
err_msg = "Rotated NMS with 0 degree is incompatible with horizontal NMS for IoU={}" | |
for iou in [0.2, 0.5, 0.8]: | |
backup = boxes.clone() | |
keep_ref = batched_nms(boxes, scores, idxs, iou) | |
assert torch.allclose(boxes, backup), "boxes modified by batched_nms" | |
backup = rotated_boxes.clone() | |
keep = batched_nms_rotated(rotated_boxes, scores, idxs, iou) | |
assert torch.allclose( | |
rotated_boxes, backup | |
), "rotated_boxes modified by batched_nms_rotated" | |
# Occasionally the gap can be large if there are many IOU on the threshold boundary | |
self.assertLessEqual(nms_edit_distance(keep, keep_ref), 5, err_msg.format(iou)) | |
def test_batched_nms_rotated_0_degree_cuda(self): | |
self.test_batched_nms_rotated_0_degree_cpu(device="cuda") | |
def test_nms_rotated_0_degree_cpu(self, device="cpu"): | |
N = 1000 | |
boxes, scores = self._create_tensors(N, device=device) | |
rotated_boxes = torch.zeros(N, 5, device=device) | |
rotated_boxes[:, 0] = (boxes[:, 0] + boxes[:, 2]) / 2.0 | |
rotated_boxes[:, 1] = (boxes[:, 1] + boxes[:, 3]) / 2.0 | |
rotated_boxes[:, 2] = boxes[:, 2] - boxes[:, 0] | |
rotated_boxes[:, 3] = boxes[:, 3] - boxes[:, 1] | |
err_msg = "Rotated NMS incompatible between CPU and reference implementation for IoU={}" | |
for iou in [0.2, 0.5, 0.8]: | |
keep_ref = self.reference_horizontal_nms(boxes, scores, iou) | |
keep = nms_rotated(rotated_boxes, scores, iou) | |
self.assertLessEqual(nms_edit_distance(keep, keep_ref), 1, err_msg.format(iou)) | |
def test_nms_rotated_0_degree_cuda(self): | |
self.test_nms_rotated_0_degree_cpu(device="cuda") | |
def test_nms_rotated_90_degrees_cpu(self): | |
N = 1000 | |
boxes, scores = self._create_tensors(N) | |
rotated_boxes = torch.zeros(N, 5) | |
rotated_boxes[:, 0] = (boxes[:, 0] + boxes[:, 2]) / 2.0 | |
rotated_boxes[:, 1] = (boxes[:, 1] + boxes[:, 3]) / 2.0 | |
# Note for rotated_boxes[:, 2] and rotated_boxes[:, 3]: | |
# widths and heights are intentionally swapped here for 90 degrees case | |
# so that the reference horizontal nms could be used | |
rotated_boxes[:, 2] = boxes[:, 3] - boxes[:, 1] | |
rotated_boxes[:, 3] = boxes[:, 2] - boxes[:, 0] | |
rotated_boxes[:, 4] = torch.ones(N) * 90 | |
err_msg = "Rotated NMS incompatible between CPU and reference implementation for IoU={}" | |
for iou in [0.2, 0.5, 0.8]: | |
keep_ref = self.reference_horizontal_nms(boxes, scores, iou) | |
keep = nms_rotated(rotated_boxes, scores, iou) | |
self.assertLessEqual(nms_edit_distance(keep, keep_ref), 1, err_msg.format(iou)) | |
def test_nms_rotated_180_degrees_cpu(self): | |
N = 1000 | |
boxes, scores = self._create_tensors(N) | |
rotated_boxes = torch.zeros(N, 5) | |
rotated_boxes[:, 0] = (boxes[:, 0] + boxes[:, 2]) / 2.0 | |
rotated_boxes[:, 1] = (boxes[:, 1] + boxes[:, 3]) / 2.0 | |
rotated_boxes[:, 2] = boxes[:, 2] - boxes[:, 0] | |
rotated_boxes[:, 3] = boxes[:, 3] - boxes[:, 1] | |
rotated_boxes[:, 4] = torch.ones(N) * 180 | |
err_msg = "Rotated NMS incompatible between CPU and reference implementation for IoU={}" | |
for iou in [0.2, 0.5, 0.8]: | |
keep_ref = self.reference_horizontal_nms(boxes, scores, iou) | |
keep = nms_rotated(rotated_boxes, scores, iou) | |
self.assertLessEqual(nms_edit_distance(keep, keep_ref), 1, err_msg.format(iou)) | |
class TestScriptable(unittest.TestCase): | |
def setUp(self): | |
class TestingModule(torch.nn.Module): | |
def forward(self, boxes, scores, threshold): | |
return nms_rotated(boxes, scores, threshold) | |
self.module = TestingModule() | |
def test_scriptable_cpu(self): | |
m = deepcopy(self.module).cpu() | |
_ = torch.jit.script(m) | |
def test_scriptable_cuda(self): | |
m = deepcopy(self.module).cuda() | |
_ = torch.jit.script(m) | |
if __name__ == "__main__": | |
unittest.main() | |