如何在 Android 中加载多通道 EXR

问题描述

我正在使用 OpenCV for Android 来加载 EXR 图像:

I'm using OpenCV for Android like this to to load an EXR image:

String testImgPath = "/storage/sdcard0/test2.exr"; //I know better than to hardcode paths. This is just a test.
Mat mRgba = Highgui.imread(testImgPath, Highgui.CV_LOAD_IMAGE_ANYCOLOR|Highgui.CV_LOAD_IMAGE_ANYDEPTH);

这适用于图像的前 3 个通道(RGB 排序除外).我可以像这样显示结果矩阵:

This works for the first 3 channels of an image (RGB ordering aside). I can display the resulting matrix like this:

Bitmap img = Bitmap.createBitmap(mRgba.cols(), mRgba.rows(), Bitmap.Config.ARGB_8888);
Utils.matToBitmap(mRgba, img);
imgView.setImageBitmap(img);

但无论我使用 imload 的标志组合如何，当我知道我的测试图像包含 9 个通道时，我从未看到通道数大于 3 (CV_32FC3).其中嵌入了 3 个 3 通道图像.如何使用 OpenCV 或其他方法访问这些额外的频道?

But regardless of the combination of flags I use with imload, I never see a channel count greater than 3 (CV_32FC3) when I know for a fact my test image contains 9 channels. There are 3, 3-channel images embedded within it. How can I access these extra channels using OpenCV or other methods?

谢谢，杰森

推荐答案

我刚刚快速浏览了 grfmt_exr.cpp.ExrDecoder::readHeader() 似乎只是假设图像是 RGB 格式或亮度/色度格式.因此，我认为您不能将 imread() 与您的 9 通道图像一起使用.

I just had a quick look at grfmt_exr.cpp. ExrDecoder::readHeader() seems to just assume that the image is in RGB format or luminance/chroma format. Therefore I think that you cannot use imread() with your 9 channel image.

OpenCV 编解码器建立在 OpenCV 源代码中包含的 ILM OpenEXR 库之上，因此如果您想编写一些 C++ 代码，请参阅 http://www.openexr.com/ReadingAndWritingImageFiles.pdf.openexr4j 可能是另一种可能性(但我从未使用过).

The OpenCV codec is built on top of the ILM OpenEXR library which is included with the OpenCV source, so if you want to write some C++ code, see http://www.openexr.com/ReadingAndWritingImageFiles.pdf. openexr4j might be another possibility (but I have never used it).

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