opencv / opencv/opencv-python

cv2.applyColorMap got different result shape between 4.x and 5.x

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Description

import numpy as np
import cv2

colors = cv2.applyColorMap(np.array([0, 63, 127, 191, 255], dtype=np.uint8), cv2.COLORMAP_PARULA)
print('shape', colors.shape)

opencv-python 4.x got shape (5, 1, 3)

# pip list | grep -e cv -e numpy
numpy                                  2.4.6
opencv-python                          4.13.0.92

Python version 3.11.9

opencv-python 5.x got shape (1, 5, 3)

# pip list | grep -e cv -e numpy
numpy                                  2.4.6
opencv-python                          5.0.0.93


Python version 3.11.9

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First steps

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  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by running the provided cv2.applyColorMap snippet with the reported opencv-python 4.x and 5.x versions, then inspect the package or upstream entry point responsible for this behavior. Compare the resulting shape against existing tests or project guidance; done means the version difference is resolved or its intended behavior is clearly documented with regression coverage.

Written by the indexing model from the issue text.

Assessment

Tech stack
opencv, python
Domain
computer-vision
Issue type
Bug
Difficulty
3/5
Estimated time
1-2 days
Activity status
Active
Clarity
Mostly clear
Newbie friendliness
55/100

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