Describe the feature and motivation

Currently (OpenCV 4.11), cv::threshold() supports auto-threshold binarizations OTSU and TRIANGLE and returns the computed threshold value.
It's a pity that there is no API to only query that auto-threshold without actually performing the thresholding.

To avoid adding an API for that and do not duplicate any code, a very easy fix would be to add some flag cv::THRESH_DISABLE cv::THRESH_DRYRUN specifically for that purpose.

However, cv::threshold() also has a big limitation : it does not support masking. I would like to add such a cv::thresholdWithMask() (or a cv::threshold() overload with additional mask parameter). But if this new API is created, cv::THRESH_DISABLE cv::THRESH_DRYRUN could be irrelevant, replaced by a boolean parameter of the new function.

• would a PR cv::thresholdWithMask() (or cv::threshold() overload) be accepted or is there a reason why thresholding does not support masking ?
• which is better, cv::thresholdWithMask() or cv::threshold() overload ?
• is the flag cv::THRESH_DISABLE cv::THRESH_DRYRUN a better idea than some cv::getThresholdAutoValue() ?
• is the flag cv::THRESH_DISABLE cv::THRESH_DRYRUN a better idea than some specific boolean input parameter ?

[edit]
For future readers and contributors :
From reviewers :

We recommend to use another name like thresholdWithMask to reduce chance of API collision in Python and Java.