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docs(imgproc): correct the documented Sobel kernel size range - #30661 ## Problem `cv::Sobel` and `cv::getDerivKernels` document the kernel size as > `@param ksize size of the extended Sobel kernel; it must be 1, 3, 5, or 7.` > `@param ksize Aperture size. It can be FILTER_SCHARR, 1, 3, 5, or 7.` but `getDerivKernels` (modules/imgproc/src/deriv.cpp) actually enforces a different constraint: ```cpp if( _ksize % 2 == 0 || _ksize > 31 ) CV_Error( cv::Error::StsOutOfRange, "The kernel size must be odd and not larger than 31" ); ``` so every odd size up to 31 is accepted, and `FILTER_SCHARR` (-1) selects the 3x3 Scharr kernels. Reproduced with opencv-python-headless 5.0.0: ``` getDerivKernels(1, 0, 9) -> OK, 9-tap kernel getDerivKernels(1, 0, 15) -> OK, 15-tap kernel getDerivKernels(1, 0, 31) -> OK, 31-tap kernel getDerivKernels(1, 0, 33) -> error: "The kernel size must be odd and not larger than 31" getDerivKernels(1, 0, -1) -> OK (Scharr 3x3) cv2.Sobel(img, cv2.CV_32F, 1, 0, ksize=9/15) -> OK cv2.Sobel(img, cv2.CV_32F, 1, 0, ksize=101) -> error (out of range) ``` ## Change Documentation-only: the two `@param ksize` entries now state the constraint the implementation enforces (odd, not larger than 31) while keeping 1, 3, 5, 7 as the typical choices. No code change. Signed-off-by: NUAAwqy <162230229@nuaa.edu.cn>
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