Robust threshold estimation for images with unimodal histograms

This article introduces a method to determine in a robust manner the threshold in highly noisy gradient images. To enhance the robustness, the proposed technique is based on a piecewise linear regression to fit the whole descending slope of the histogram, rather than the search of some specific points. The algorithm gives a reliable estimation of the threshold, and is practically insensitive to the noise distribution, to the quantity of edge pixels to segment, and to random histogram fluctuations.