Describe the doc issue

The documentation for the cv::StereoBM class mentions several methods, including but not limited to getROI1, getROI2, getTextureThreshold , setPreFilterSize, which are not clear in their functionality and how the output disparity image is affected when they are tuned. This problem has been consistent since 3.x, and continues into the 4.12.0-dev and 5.0.0 branch documentation.

Fix suggestion

If someone can explain what the parameters are and in what context they need to be tuned for, then I'm willing to open a PR to add the explanations to the documentation.