Threshold selection
T = otsu(im) is an optimal threshold for binarizing an image with a bimodal intensity histogram. T is a scalar threshold that maximizes the variance between the classes of pixels below and above the thresold T.
t = otsu(im); idisp(im >= t);
| 'levels', N | Number of grey levels to use if image is float (default 256) |
| 'valley', S | Standard deviation for the Gaussian weighted valley emphasis option |
A Threshold Selection Method from Gray-Level Histograms, N. otsu IEEE Trans. Systems, Man and Cybernetics Vol SMC-9(1), Jan 1979, pp 62-66
An improved method for image thresholding on the valley-emphasis method H-F Ng, D. Jargalsaikhan etal Signal and Info Proc. Assocn. Annual Summit and Conf (APSIPA) 2013 pp 1-4
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