A two-stage Otsu´S thresholding based method on a 2D histogram

We propose a fast and robust thresholding method that can overcome the shortcoming of the traditional and two-dimensional (2D) Otsu´s methods. Our method takes advantage of the gradient gray level to divide the 2D histogram region, and applies the traditional Otsu´s thresholding method twice on two projection histograms to separate the regions of interest from the background. The experimental results show that our method is robust against noise, and it requires less computational time than the 2D Otsu´s and four other thresholding methods, which also give highly satisfactory and comparable results.