Returns number of threads used by OpenCV for parallel regions

n = cv.Utils.getNumThreads()

Output

• n number of threads.

The exact meaning of the return value depends on the threading framework used by OpenCV library:

• TBB The number of threads, that OpenCV will try to use for parallel regions. If there is any tbb::thread_scheduler_init in user code conflicting with OpenCV, then function returns default number of threads used by TBB library.
• OpenMP An upper bound on the number of threads that could be used to form a new team.
• Concurrency The number of threads, that OpenCV will try to use for parallel regions.
• GCD Unsupported; returns the GCD thread pool limit (512) for compatibility.
• C= The number of threads, that OpenCV will try to use for parallel regions, if before called setNumThreads with threads > 0, otherwise returns the number of logical CPUs, available for the process.