Thresholds is a list of grayscale upper and lower tuples.
[(100, 255), (0, 50)] and etc. All pixels with values in it are considered part of a blob, all pixels out of it are not the blob. The API is clear on this…
Pixels_threshold removes blobs that are too small (e.g. noise) from the list of output blobs if they don’t meet he pixel threshold. I.e. the number of connected pixels in the blob is less than the threshold.