System Information

OpenCV python version: 4.6.0.66
Operating System: Win 10 64bit
Python version: 3.9.7

Detailed description

When calling bilateralFilter in python with a sigmaColor value of 0, the function produces the same result as if sigmaColor were 1. This is a huge problem for images stored as 0 to 1 float32 values.

Here is an example:

diameter=10, sigmaColor=0.39, sigmaSpace=100

diameter=10, sigmaColor=0.039, sigmaSpace=100

diameter=10, sigmaColor=0.0039, sigmaSpace=100

diameter=10, sigmaColor=0, sigmaSpace=100

diameter=10, sigmaColor=1, sigmaSpace=100

This behavior is not documented.

Steps to reproduce

Have any image that is a numpy array with float32 values between 0 and 1.

diameter=10
sigma_color=0.0
sigma_space=100
cv2.bilateralFilter(
            image,
            diameter,
            sigma_color,
            sigma_space,
            borderType=cv2.BORDER_REFLECT_101,
        )

Issue submission checklist

• I report the issue, it's not a question
• I checked the problem with documentation, FAQ, open issues, forum.opencv.org, Stack Overflow, etc and have not found any solution
• I updated to the latest OpenCV version and the issue is still there
• There is reproducer code and related data files (videos, images, onnx, etc)