imgcodecs: OpenEXR multispectral read/write support #27485
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Adds capability to read and write multispectral (>4 channels) images in OpenEXR format.
solving warning C4800
| ASSERT_TRUE(cv::imwrite(filenameOutput, img)); | ||
| const Mat img2 = cv::imread(filenameOutput, IMREAD_UNCHANGED); | ||
| ASSERT_EQ(img2.type(), img.type()); | ||
| ASSERT_EQ(img2.size(), img.size()); |
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Temporary file will not be removed if test fail on this or previous asserts. We need to use EXPECT.
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I am new to gtest so I don't know that EXPECT should be used. I copied the pattern which was in previous tests: readWrite_32FC1, readWrite_32FC3.
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EXPECT_EQ(img2.type(), img.type());
EXPECT_EQ(img2.size(), img.size());
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I changed that only in my test readWrite_32FC7, but the same is in several other tests.
| TEST(Imgcodecs_EXR, readWrite_32FC7) | ||
| { // 0-6 channels (multispectral) | ||
| const string root = cvtest::TS::ptr()->get_data_path(); | ||
| const string filenameInput = root + "readwrite/test32FC7.exr"; |
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imho using a generated cv::Mat here instead of adding an extra test file to opencv_extra is better.
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TEST(Imgcodecs_EXR, readWrite_32FC7)
{ // 0-6 channels (multispectral)
const string filename = cv::tempfile(".exr");
const Size sz(3, 5);
Mat img(sz, CV_MAKETYPE(CV_32F, 7));
img.at<cv::Vec<float, 7>>(0, 0)[0] = 101.125;
img.at<cv::Vec<float, 7>>(2, 1)[3] = 203.500;
img.at<cv::Vec<float, 7>>(4, 2)[6] = 305.875;
ASSERT_TRUE(cv::imwrite(filename, img));
const Mat img2 = cv::imread(filename, IMREAD_UNCHANGED);
EXPECT_EQ(img2.type(), img.type());
EXPECT_EQ(img2.size(), img.size());
EXPECT_LE(cvtest::norm(img, img2, NORM_INF | NORM_RELATIVE), 1e-3);
const Mat img3 = cv::imread(filename, IMREAD_GRAYSCALE);
ASSERT_TRUE(img3.empty());
const Mat img4 = cv::imread(filename, IMREAD_COLOR);
ASSERT_TRUE(img4.empty());
EXPECT_EQ(0, remove(filename.c_str()));
}
output
[ RUN ] Imgcodecs_EXR.readWrite_32FC7
[ERROR:0@3.966] global loadsave.cpp:594 cv::imread_ imread_('C:\Users\aidata\AppData\Local\Temp\ocvBA1A.tmp.exr'): can't read data: OpenCV(4.12.0-pre) C:\projects\opencv\modules\imgcodecs\src\grfmt_exr.cpp:260: error: (-2:Unspecified error) in function 'bool __cdecl cv::ExrDecoder::readData(class cv::Mat &)'
> OpenCV EXR decoder needs more number of channels for multispectral images. Use cv::IMREAD_UNCHANGED mode for imread. (expected: 'img.channels() == CV_MAT_CN(type())'), where
> 'img.channels()' is 1
> must be equal to
> 'CV_MAT_CN(type())' is 7
[ERROR:0@3.966] global loadsave.cpp:594 cv::imread_ imread_('C:\Users\aidata\AppData\Local\Temp\ocvBA1A.tmp.exr'): can't read data: OpenCV(4.12.0-pre) C:\projects\opencv\modules\imgcodecs\src\grfmt_exr.cpp:260: error: (-2:Unspecified error) in function 'bool __cdecl cv::ExrDecoder::readData(class cv::Mat &)'
> OpenCV EXR decoder needs more number of channels for multispectral images. Use cv::IMREAD_UNCHANGED mode for imread. (expected: 'img.channels() == CV_MAT_CN(type())'), where
> 'img.channels()' is 3
> must be equal to
> 'CV_MAT_CN(type())' is 7
[ OK ] Imgcodecs_EXR.readWrite_32FC7 (5 ms)
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EXPECT_EQ(0, remove(filename.c_str())); const Mat img3 = cv::imread(filename, IMREAD_GRAYSCALE); ASSERT_TRUE(img3.empty()); const Mat img4 = cv::imread(filename, IMREAD_COLOR); ASSERT_TRUE(img4.empty()); }
Removing file is before testing grayscale and color in current branch. It prints error message as you can't load multispectral image as GRAYSCALE or COLOR.
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EXPECT_EQ(0, remove(filename.c_str())); const Mat img3 = cv::imread(filename, IMREAD_GRAYSCALE); ASSERT_TRUE(img3.empty()); const Mat img4 = cv::imread(filename, IMREAD_COLOR); ASSERT_TRUE(img4.empty()); }Removing file is before testing grayscale and color in current branch. It prints error message as you can't load multispectral image as GRAYSCALE or COLOR.
i fixed it on my code
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i suggest using this
TEST(Imgcodecs_EXR, readWrite_32FC7)
{ // 0-6 channels (multispectral)
const string filename = cv::tempfile(".exr");
const Size sz(3, 5);
Mat img = Mat::zeros(sz, CV_MAKETYPE(CV_32F, 7));
img.at<cv::Vec<float, 7>>(0, 0)[0] = 101.125;
img.at<cv::Vec<float, 7>>(2, 1)[3] = 203.500;
img.at<cv::Vec<float, 7>>(4, 2)[6] = 305.875;
ASSERT_TRUE(cv::imwrite(filename, img));
const Mat img2 = cv::imread(filename, IMREAD_UNCHANGED);
EXPECT_EQ(img2.type(), img.type());
EXPECT_EQ(img2.size(), img.size());
EXPECT_LE(cvtest::norm(img, img2, NORM_INF | NORM_RELATIVE), 1e-3);
const Mat img3 = cv::imread(filename, IMREAD_GRAYSCALE);
ASSERT_TRUE(img3.empty());
const Mat img4 = cv::imread(filename, IMREAD_COLOR);
ASSERT_TRUE(img4.empty());
EXPECT_EQ(0, remove(filename.c_str()));
}
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const Size sz(3, 5);
Mat img = Mat::zeros(sz, CV_MAKETYPE(CV_32F, 7));
img.at<cv::Vec<float, 7>>(0, 0)[0] = 101.125;
img.at<cv::Vec<float, 7>>(2, 1)[3] = 203.500;
img.at<cv::Vec<float, 7>>(4, 2)[6] = 305.875;
ASSERT_TRUE(cv::imwrite(filename, img));
generates the same file at opencv/opencv_extra#1262
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I use the same pattern as tests readWrite_32FC1, readWrite_32FC3, readWrite_32FC1_half, readWrite_32FC3_half. It's generate image file upon GENERATE_DATA define. I don't know when it was called with this define so I do the new test readWrite_32FC7 same way.
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@xaos-cz thank you for your contribution. i am also a common contributor ( a bit more experienced). I think this test is to verify that the change you made is working correctly and to show if a later change breaks your code. It doesn't matter if it's similar in form to the other tests.
OpenCV Extra: opencv/opencv_extra#1262
Adds capability to read and write multispectral (>4 channels) images in OpenEXR format.
Pull Request Readiness Checklist
See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request
Patch to opencv_extra has the same branch name.