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
| const string filenameInput = root + "readwrite/test32FC7.exr"; | ||
| const string filenameOutput = cv::tempfile(".exr"); | ||
| #ifndef GENERATE_DATA | ||
| const Mat img = cv::imread(filenameInput, IMREAD_UNCHANGED); |
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How will it work in case of BGR or GRAYSCALE input?
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I tried to open the test file without parameters and got [ERROR:0@0.020] global loadsave.cpp:515 imread_ imread_('./test32FC7.exr'): can't read data: OpenCV(4.12.0-pre) /mnt/Projects/Projects/opencv/modules/imgcodecs/src/grfmt_exr.cpp:258: error: (-215:Assertion failed) m_multispectral == multispectral in function 'readData'
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The message looks cryptic. I propose to use CV_CheckXXX macro and add meaningful error message.
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How will it work in case of BGR or GRAYSCALE input?
It leaves it on previous implementation when channels <= 4
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I tried to open the test file without parameters and got `[ERROR:0@0.020] ...
I will test it today and add some error messages.
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I propose some change in calcType but it change some behaviour with 2/4-channel images and IMREAD_ANYCOLOR so left it commented out. I did some imread tests with several mode combinations for 1-5 channels. Commited version had the same results for <5 channels as the previous code.
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I won't do anything new in this request. It works as intended. The found bug I will publish as an issue.
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I believe we need to test BGR and grayscale modes too. Even if expected behavior is an exception.
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I did tests with several mode combinations (IMREAD_GRAYSCALE, IMREAD_COLOR, IMREAD_ANYCOLOR, IMREAD_ANYCOLOR | cv::IMREAD_COLOR, IMREAD_ANYDEPTH, IMREAD_ANYDEPTH | cv::IMREAD_COLOR, IMREAD_ANYDEPTH | cv::IMREAD_ANYCOLOR, IMREAD_ANYDEPTH | cv::IMREAD_ANYCOLOR | cv::IMREAD_COLOR, IMREAD_UNCHANGED), up to four channels it behaves as previous version; from five channels it supports only CV_32F and more channels, so IMREAD_UNCHANGED is suggested to use.
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I can add tests for IMREAD_GRAYSCALE, IMREAD_COLOR.
| 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.
OpenCV Extra: opencv/opencv_extra#1262
Adds capability to read and write multispectral (>4 channels) images in OpenEXR format.
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Patch to opencv_extra has the same branch name.