Fix decoding of RGB JPEG with Adobe APP14 marker #1444
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Codecov Report
@@ Coverage Diff @@
## master #1444 +/- ##
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Coverage 96.97% 96.97%
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Files 65 65
Lines 10184 10185 +1
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+ Hits 9876 9877 +1
Misses 308 308
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scaramallion
approved these changes
Jul 20, 2021
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Looks good, another thing I've been intending to do is check to see if the component names are 'R' 'G' and 'B'. |
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Describe the changes
DICOM allows JPEG steams where the image has been directly compressed in RGB color space without first transforming the image into YCbCr color space. Pillow doesn't (and cannot!) decode the pixel data correctly, because it doesn't know whether a color transformation has been applied (in DICOM specified via Photometric Interpretation). We previously addressed this issue via #878.
In the meantime, pillow has become capable of detecting the Adobe APP14 marker segment in the JPEG header (which specifies the color transformation via the transform flag) and can now decode the JPEG stream correctly if the marker segment is present (see python-pillow/Pillow#5408). The change in decoding behavior now conflicts with the decoding logic implemented in pydicom.
This PR addressed this conflict. Specifically, if the Adobe APP14 marker segment is detected in the JPEG header by Pillow, pydicom lets Pillow handle the decoding and color transformation. If the marker is absent, pydicom will provide further information to Pillow to avoid an incorrect/unnecessary color transformation.
Tasks
doc/_build/html/index.html)