Returns a threshold using data from this histogram. The computed threshold is appropriate for segmenting an image into object and background pixels and is often used to compute a segmentation threshold for blob analysis. The returned threshold divides the histogram data into two groups such that the combined variance within the groups is a minimum.

Returns a threshold using data from the given range of this histogram. The computed threshold is appropriate for segmenting an image into object and background pixels and is often used to compute a segmentation threshold for blob analysis. The threshold computation includes the left index value but excludes the right index value. This range must include at least two nonzero bins. The returned threshold will be within the range. This threshold divides the histogram data into two groups such that the combined variance within the groups is a minimum.