Merge pull request #26127 from alexlyulkov:al/blob-from-images

Faster implementation of blobFromImages for cpu nchw output #26127

Faster implementation of blobFromImage and blobFromImages for
HWC cv::Mat images -> NCHW cv::Mat
case

Running time on my pc in ms:

**blobFromImage**
```
image size            old        new   speed-up
32x32x3             0.008      0.002       4.0x
64x64x3             0.021      0.009       2.3x
128x128x3           0.164      0.037       4.4x
256x256x3           0.728      0.158       4.6x
512x512x3           3.310      0.628       5.2x
1024x1024x3        14.503      3.124       4.6x
2048x2048x3        61.647     28.049       2.2x
```

**blobFromImages**
```
image size            old        new   speed-up
16x32x32x3          0.122      0.041       3.0x
16x64x64x3          0.790      0.165       4.8x
16x128x128x3        3.313      0.652       5.1x
16x256x256x3       13.495      3.127       4.3x
16x512x512x3       58.795     28.127       2.1x
16x1024x1024x3    251.135    121.955       2.1x
16x2048x2048x3   1023.570    487.188       2.1x
```


### Pull Request Readiness Checklist

See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request

- [x] I agree to contribute to the project under Apache 2 License.
- [x] To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV
- [x] The PR is proposed to the proper branch
- [ ] There is a reference to the original bug report and related work
- [ ] There is accuracy test, performance test and test data in opencv_extra repository, if applicable
      Patch to opencv_extra has the same branch name.
- [x] The feature is well documented and sample code can be built with the project CMake
This commit is contained in:
alexlyulkov 2024-12-23 10:04:34 +03:00 committed by GitHub
parent d9a139f9e8
commit aa52dafc90
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2 changed files with 218 additions and 22 deletions

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@ -0,0 +1,66 @@
// This file is part of OpenCV project.
// It is subject to the license terms in the LICENSE file found in the top-level directory
// of this distribution and at http://opencv.org/license.html.
//
// Copyright (C) 2017, Intel Corporation, all rights reserved.
// Third party copyrights are property of their respective owners.
#include "perf_precomp.hpp"
namespace opencv_test {
using Utils_blobFromImage = TestBaseWithParam<std::vector<int>>;
PERF_TEST_P_(Utils_blobFromImage, HWC_TO_NCHW) {
std::vector<int> input_shape = GetParam();
Mat input(input_shape, CV_32FC3);
randu(input, -10.0f, 10.f);
TEST_CYCLE() {
Mat blob = blobFromImage(input);
}
SANITY_CHECK_NOTHING();
}
INSTANTIATE_TEST_CASE_P(/**/, Utils_blobFromImage,
Values(std::vector<int>{ 32, 32},
std::vector<int>{ 64, 64},
std::vector<int>{ 128, 128},
std::vector<int>{ 256, 256},
std::vector<int>{ 512, 512},
std::vector<int>{1024, 1024},
std::vector<int>{2048, 2048})
);
using Utils_blobFromImages = TestBaseWithParam<std::vector<int>>;
PERF_TEST_P_(Utils_blobFromImages, HWC_TO_NCHW) {
std::vector<int> input_shape = GetParam();
int batch = input_shape.front();
std::vector<int> input_shape_no_batch(input_shape.begin()+1, input_shape.end());
std::vector<Mat> inputs;
for (int i = 0; i < batch; i++) {
Mat input(input_shape_no_batch, CV_32FC3);
randu(input, -10.0f, 10.f);
inputs.push_back(input);
}
TEST_CYCLE() {
Mat blobs = blobFromImages(inputs);
}
SANITY_CHECK_NOTHING();
}
INSTANTIATE_TEST_CASE_P(/**/, Utils_blobFromImages,
Values(std::vector<int>{16, 32, 32},
std::vector<int>{16, 64, 64},
std::vector<int>{16, 128, 128},
std::vector<int>{16, 256, 256},
std::vector<int>{16, 512, 512},
std::vector<int>{16, 1024, 1024},
std::vector<int>{16, 2048, 2048})
);
}

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@ -126,6 +126,111 @@ Mat blobFromImagesWithParams(InputArrayOfArrays images, const Image2BlobParams&
return blob;
}
template<typename Tinp, typename Tout>
void blobFromImagesNCHWImpl(const std::vector<Mat>& images, Mat& blob_, const Image2BlobParams& param)
{
int w = images[0].cols;
int h = images[0].rows;
int wh = w * h;
int nch = images[0].channels();
CV_Assert(nch == 1 || nch == 3 || nch == 4);
int sz[] = { (int)images.size(), nch, h, w};
blob_.create(4, sz, param.ddepth);
for (size_t k = 0; k < images.size(); ++k)
{
CV_Assert(images[k].depth() == images[0].depth());
CV_Assert(images[k].channels() == images[0].channels());
CV_Assert(images[k].size() == images[0].size());
Tout* p_blob = blob_.ptr<Tout>() + k * nch * wh;
Tout* p_blob_r = p_blob;
Tout* p_blob_g = p_blob + wh;
Tout* p_blob_b = p_blob + 2 * wh;
Tout* p_blob_a = p_blob + 3 * wh;
if (param.swapRB)
std::swap(p_blob_r, p_blob_b);
for (size_t i = 0; i < h; ++i)
{
const Tinp* p_img_row = images[k].ptr<Tinp>(i);
if (nch == 1)
{
for (size_t j = 0; j < w; ++j)
{
p_blob[i * w + j] = p_img_row[j];
}
}
else if (nch == 3)
{
for (size_t j = 0; j < w; ++j)
{
p_blob_r[i * w + j] = p_img_row[j * 3 ];
p_blob_g[i * w + j] = p_img_row[j * 3 + 1];
p_blob_b[i * w + j] = p_img_row[j * 3 + 2];
}
}
else // if (nch == 4)
{
for (size_t j = 0; j < w; ++j)
{
p_blob_r[i * w + j] = p_img_row[j * 4 ];
p_blob_g[i * w + j] = p_img_row[j * 4 + 1];
p_blob_b[i * w + j] = p_img_row[j * 4 + 2];
p_blob_a[i * w + j] = p_img_row[j * 4 + 3];
}
}
}
}
if (param.mean == Scalar() && param.scalefactor == Scalar::all(1.0))
return;
CV_CheckTypeEQ(param.ddepth, CV_32F, "Scaling and mean substraction is supported only for CV_32F blob depth");
for (size_t k = 0; k < images.size(); ++k)
{
for (size_t ch = 0; ch < nch; ++ch)
{
float cur_mean = param.mean[ch];
float cur_scale = param.scalefactor[ch];
Tout* p_blob = blob_.ptr<Tout>() + k * nch * wh + ch * wh;
for (size_t i = 0; i < wh; ++i)
{
p_blob[i] = (p_blob[i] - cur_mean) * cur_scale;
}
}
}
}
template<typename Tout>
void blobFromImagesNCHW(const std::vector<Mat>& images, Mat& blob_, const Image2BlobParams& param)
{
if (images[0].depth() == CV_8U)
blobFromImagesNCHWImpl<uint8_t, Tout>(images, blob_, param);
else if (images[0].depth() == CV_8S)
blobFromImagesNCHWImpl<int8_t, Tout>(images, blob_, param);
else if (images[0].depth() == CV_16U)
blobFromImagesNCHWImpl<uint16_t, Tout>(images, blob_, param);
else if (images[0].depth() == CV_16S)
blobFromImagesNCHWImpl<int16_t, Tout>(images, blob_, param);
else if (images[0].depth() == CV_32S)
blobFromImagesNCHWImpl<int32_t, Tout>(images, blob_, param);
else if (images[0].depth() == CV_32F)
blobFromImagesNCHWImpl<float, Tout>(images, blob_, param);
else if (images[0].depth() == CV_64F)
blobFromImagesNCHWImpl<double, Tout>(images, blob_, param);
else
CV_Error(Error::BadDepth, "Unsupported input image depth for blobFromImagesNCHW");
}
template<typename Tout>
void blobFromImagesNCHW(const std::vector<UMat>& images, UMat& blob_, const Image2BlobParams& param)
{
CV_Error(Error::StsNotImplemented, "");
}
template<class Tmat>
void blobFromImagesWithParamsImpl(InputArrayOfArrays images_, Tmat& blob_, const Image2BlobParams& param)
{
@ -154,19 +259,6 @@ void blobFromImagesWithParamsImpl(InputArrayOfArrays images_, Tmat& blob_, const
Scalar scalefactor = param.scalefactor;
Scalar mean = param.mean;
if (param.swapRB)
{
if (nch > 2)
{
std::swap(mean[0], mean[2]);
std::swap(scalefactor[0], scalefactor[2]);
}
else
{
CV_LOG_WARNING(NULL, "Red/blue color swapping requires at least three image channels.");
}
}
for (size_t i = 0; i < images.size(); i++)
{
Size imgSize = images[i].size();
@ -203,18 +295,35 @@ void blobFromImagesWithParamsImpl(InputArrayOfArrays images_, Tmat& blob_, const
resize(images[i], images[i], size, 0, 0, INTER_LINEAR);
}
}
if (images[i].depth() == CV_8U && param.ddepth == CV_32F)
images[i].convertTo(images[i], CV_32F);
subtract(images[i], mean, images[i]);
multiply(images[i], scalefactor, images[i]);
}
size_t nimages = images.size();
Tmat image0 = images[0];
CV_Assert(image0.dims == 2);
if (std::is_same<Tmat, Mat>::value && param.datalayout == DNN_LAYOUT_NCHW)
{
// Fast implementation for HWC cv::Mat images -> NCHW cv::Mat blob
if (param.ddepth == CV_8U)
blobFromImagesNCHW<uint8_t>(images, blob_, param);
else
blobFromImagesNCHW<float>(images, blob_, param);
return;
}
if (param.swapRB)
{
if (nch > 2)
{
std::swap(mean[0], mean[2]);
std::swap(scalefactor[0], scalefactor[2]);
}
else
{
CV_LOG_WARNING(NULL, "Red/blue color swapping requires at least three image channels.");
}
}
if (param.datalayout == DNN_LAYOUT_NCHW)
{
if (nch == 3 || nch == 4)
@ -225,7 +334,14 @@ void blobFromImagesWithParamsImpl(InputArrayOfArrays images_, Tmat& blob_, const
for (size_t i = 0; i < nimages; i++)
{
const Tmat& image = images[i];
Tmat& image = images[i];
if (image.depth() == CV_8U && param.ddepth == CV_32F)
image.convertTo(image, CV_32F);
if (mean != Scalar())
subtract(image, mean, image);
if (scalefactor != Scalar::all(1.0))
multiply(image, scalefactor, image);
CV_Assert(image.depth() == blob_.depth());
nch = image.channels();
CV_Assert(image.dims == 2 && (nch == 3 || nch == 4));
@ -250,7 +366,14 @@ void blobFromImagesWithParamsImpl(InputArrayOfArrays images_, Tmat& blob_, const
for (size_t i = 0; i < nimages; i++)
{
const Tmat& image = images[i];
Tmat& image = images[i];
if (image.depth() == CV_8U && param.ddepth == CV_32F)
image.convertTo(image, CV_32F);
if (mean != Scalar())
subtract(image, mean, image);
if (scalefactor != Scalar::all(1.0))
multiply(image, scalefactor, image);
CV_Assert(image.depth() == blob_.depth());
nch = image.channels();
CV_Assert(image.dims == 2 && (nch == 1));
@ -269,7 +392,14 @@ void blobFromImagesWithParamsImpl(InputArrayOfArrays images_, Tmat& blob_, const
int subMatType = CV_MAKETYPE(param.ddepth, nch);
for (size_t i = 0; i < nimages; i++)
{
const Tmat& image = images[i];
Tmat& image = images[i];
if (image.depth() == CV_8U && param.ddepth == CV_32F)
image.convertTo(image, CV_32F);
if (mean != Scalar())
subtract(image, mean, image);
if (scalefactor != Scalar::all(1.0))
multiply(image, scalefactor, image);
CV_Assert(image.depth() == blob_.depth());
CV_Assert(image.channels() == image0.channels());
CV_Assert(image.size() == image0.size());