Calculate Otsu's threshold — otsu • pliman

Given a numeric vector with the pixel's intensities, returns the threshold value based on Otsu's method, which minimizes the combined intra-class variance

Usage

otsu(values)

Arguments

values: A numeric vector with the pixel values.

Value

A double (threshold value).

References

Otsu, N. 1979. Threshold selection method from gray-level histograms. IEEE Trans Syst Man Cybern SMC-9(1): 62–66. doi: doi:10.1109/tsmc.1979.4310076

Examples

if (interactive() && requireNamespace("EBImage")) {
img <- image_pliman("soybean_touch.jpg")
thresh <- otsu(img@.Data[,,3])
plot(img[,,3] < thresh)
}