pytorch / pytorch/vision

torchvision.transforms.functional.adjust_hue does not respect alpha channel

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enhancement help wanted module: documentation module: transforms
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Python
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Description

🐛 Bug

when working with RGBA images, the adjust_hue function does not seem to respect the alpha channel and imposes a max_value of 255 after the transform. Taking a quick look at the source code, it seems that the image is immediately converted to HSV without retaining the alpha channel. It should be a quick fix to retain the alpha channel and include it when merging back into RGBA.

To Reproduce

Steps to reproduce the behavior:

img = Image.open('xyz.png')
img_ = adjust_hue(img, 0.1)
print(np.array(img.split()[-1]).mean())
print(np.array(img_.split()[-1]).mean())

cc @vfdev-5

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Research direction

Start at torchvision.transforms.functional.adjust_hue and reproduce the reported behavior with an RGBA image using the example in the issue. Verify that the alpha channel is retained through the transform and that its values are unchanged in the returned image.

Written by the indexing model from the issue text.

Assessment

Tech stack
python
Domain
computer-vision
Issue type
Bug
Difficulty
2/5
Estimated time
1-3 hours
Activity status
Stale
Clarity
Clearly specified
Newbie friendliness
50/100

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