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# Copyright (c) Facebook, Inc. and its affiliates. | |
import numpy as np | |
import unittest | |
from copy import copy | |
import cv2 | |
import torch | |
from fvcore.common.benchmark import benchmark | |
from torch.nn import functional as F | |
from detectron2.layers.roi_align import ROIAlign, roi_align | |
class ROIAlignTest(unittest.TestCase): | |
def test_forward_output(self): | |
input = np.arange(25).reshape(5, 5).astype("float32") | |
""" | |
0 1 2 3 4 | |
5 6 7 8 9 | |
10 11 12 13 14 | |
15 16 17 18 19 | |
20 21 22 23 24 | |
""" | |
output = self._simple_roialign(input, [1, 1, 3, 3], (4, 4), aligned=False) | |
output_correct = self._simple_roialign(input, [1, 1, 3, 3], (4, 4), aligned=True) | |
# without correction: | |
old_results = [ | |
[7.5, 8, 8.5, 9], | |
[10, 10.5, 11, 11.5], | |
[12.5, 13, 13.5, 14], | |
[15, 15.5, 16, 16.5], | |
] | |
# with 0.5 correction: | |
correct_results = [ | |
[4.5, 5.0, 5.5, 6.0], | |
[7.0, 7.5, 8.0, 8.5], | |
[9.5, 10.0, 10.5, 11.0], | |
[12.0, 12.5, 13.0, 13.5], | |
] | |
# This is an upsampled version of [[6, 7], [11, 12]] | |
self.assertTrue(np.allclose(output.flatten(), np.asarray(old_results).flatten())) | |
self.assertTrue( | |
np.allclose(output_correct.flatten(), np.asarray(correct_results).flatten()) | |
) | |
# Also see similar issues in tensorflow at | |
# https://github.com/tensorflow/tensorflow/issues/26278 | |
def test_resize(self): | |
H, W = 30, 30 | |
input = np.random.rand(H, W).astype("float32") * 100 | |
box = [10, 10, 20, 20] | |
output = self._simple_roialign(input, box, (5, 5), aligned=True) | |
input2x = cv2.resize(input, (W // 2, H // 2), interpolation=cv2.INTER_LINEAR) | |
box2x = [x / 2 for x in box] | |
output2x = self._simple_roialign(input2x, box2x, (5, 5), aligned=True) | |
diff = np.abs(output2x - output) | |
self.assertTrue(diff.max() < 1e-4) | |
def test_grid_sample_equivalence(self): | |
H, W = 30, 30 | |
input = np.random.rand(H, W).astype("float32") * 100 | |
box = [10, 10, 20, 20] | |
for ratio in [1, 2, 3]: | |
output = self._simple_roialign(input, box, (5, 5), sampling_ratio=ratio) | |
output_grid_sample = grid_sample_roi_align( | |
torch.from_numpy(input[None, None, :, :]).float(), | |
torch.as_tensor(box).float()[None, :], | |
5, | |
1.0, | |
ratio, | |
) | |
self.assertTrue(torch.allclose(output, output_grid_sample)) | |
def _simple_roialign(self, img, box, resolution, sampling_ratio=0, aligned=True): | |
""" | |
RoiAlign with scale 1.0. | |
""" | |
if isinstance(resolution, int): | |
resolution = (resolution, resolution) | |
op = ROIAlign(resolution, 1.0, sampling_ratio, aligned=aligned) | |
input = torch.from_numpy(img[None, None, :, :].astype("float32")) | |
rois = [0] + list(box) | |
rois = torch.from_numpy(np.asarray(rois)[None, :].astype("float32")) | |
output = op.forward(input, rois) | |
if torch.cuda.is_available(): | |
output_cuda = op.forward(input.cuda(), rois.cuda()).cpu() | |
self.assertTrue(torch.allclose(output, output_cuda)) | |
return output[0, 0] | |
def _simple_roialign_with_grad(self, img, box, resolution, device): | |
if isinstance(resolution, int): | |
resolution = (resolution, resolution) | |
op = ROIAlign(resolution, 1.0, 0, aligned=True) | |
input = torch.from_numpy(img[None, None, :, :].astype("float32")) | |
rois = [0] + list(box) | |
rois = torch.from_numpy(np.asarray(rois)[None, :].astype("float32")) | |
input = input.to(device=device) | |
rois = rois.to(device=device) | |
input.requires_grad = True | |
output = op.forward(input, rois) | |
return input, output | |
def test_empty_box(self): | |
img = np.random.rand(5, 5) | |
box = [3, 4, 5, 4] | |
o = self._simple_roialign(img, box, 7) | |
self.assertTrue(o.shape == (7, 7)) | |
self.assertTrue((o == 0).all()) | |
for dev in ["cpu"] + ["cuda"] if torch.cuda.is_available() else []: | |
input, output = self._simple_roialign_with_grad(img, box, 7, torch.device(dev)) | |
output.sum().backward() | |
self.assertTrue(torch.allclose(input.grad, torch.zeros_like(input))) | |
def test_empty_batch(self): | |
input = torch.zeros(0, 3, 10, 10, dtype=torch.float32) | |
rois = torch.zeros(0, 5, dtype=torch.float32) | |
op = ROIAlign((7, 7), 1.0, 0, aligned=True) | |
output = op.forward(input, rois) | |
self.assertTrue(output.shape == (0, 3, 7, 7)) | |
def grid_sample_roi_align(input, boxes, output_size, scale, sampling_ratio): | |
# unlike true roi_align, this does not support different batch_idx | |
from detectron2.projects.point_rend.point_features import ( | |
generate_regular_grid_point_coords, | |
get_point_coords_wrt_image, | |
point_sample, | |
) | |
N, _, H, W = input.shape | |
R = len(boxes) | |
assert N == 1 | |
boxes = boxes * scale | |
grid = generate_regular_grid_point_coords(R, output_size * sampling_ratio, device=boxes.device) | |
coords = get_point_coords_wrt_image(boxes, grid) | |
coords = coords / torch.as_tensor([W, H], device=coords.device) # R, s^2, 2 | |
res = point_sample(input, coords.unsqueeze(0), align_corners=False) # 1,C, R,s^2 | |
res = ( | |
res.squeeze(0) | |
.permute(1, 0, 2) | |
.reshape(R, -1, output_size * sampling_ratio, output_size * sampling_ratio) | |
) | |
res = F.avg_pool2d(res, sampling_ratio) | |
return res | |
def benchmark_roi_align(): | |
def random_boxes(mean_box, stdev, N, maxsize): | |
ret = torch.rand(N, 4) * stdev + torch.tensor(mean_box, dtype=torch.float) | |
ret.clamp_(min=0, max=maxsize) | |
return ret | |
def func(shape, nboxes_per_img, sampling_ratio, device, box_size="large"): | |
N, _, H, _ = shape | |
input = torch.rand(*shape) | |
boxes = [] | |
batch_idx = [] | |
for k in range(N): | |
if box_size == "large": | |
b = random_boxes([80, 80, 130, 130], 24, nboxes_per_img, H) | |
else: | |
b = random_boxes([100, 100, 110, 110], 4, nboxes_per_img, H) | |
boxes.append(b) | |
batch_idx.append(torch.zeros(nboxes_per_img, 1, dtype=torch.float32) + k) | |
boxes = torch.cat(boxes, axis=0) | |
batch_idx = torch.cat(batch_idx, axis=0) | |
boxes = torch.cat([batch_idx, boxes], axis=1) | |
input = input.to(device=device) | |
boxes = boxes.to(device=device) | |
def bench(): | |
if False and sampling_ratio > 0 and N == 1: | |
# enable to benchmark grid_sample (slower) | |
grid_sample_roi_align(input, boxes[:, 1:], 7, 1.0, sampling_ratio) | |
else: | |
roi_align(input, boxes, 7, 1.0, sampling_ratio, True) | |
if device == "cuda": | |
torch.cuda.synchronize() | |
return bench | |
def gen_args(arg): | |
args = [] | |
for size in ["small", "large"]: | |
for ratio in [0, 2]: | |
args.append(copy(arg)) | |
args[-1]["sampling_ratio"] = ratio | |
args[-1]["box_size"] = size | |
return args | |
arg = dict(shape=(1, 512, 256, 256), nboxes_per_img=512, device="cuda") | |
benchmark(func, "cuda_roialign", gen_args(arg), num_iters=20, warmup_iters=1) | |
arg.update({"device": "cpu", "shape": (1, 256, 128, 128)}) | |
benchmark(func, "cpu_roialign", gen_args(arg), num_iters=5, warmup_iters=1) | |
if __name__ == "__main__": | |
if torch.cuda.is_available(): | |
benchmark_roi_align() | |
unittest.main() | |