Color edge information can be used to measure or recognize objects in images. False color edges introduced by noise are conventionally eliminated by thresholding. The problem is how to find such threshold value. We present and empirically verify a principled method for automatic, local determination of the threshold value. The method is based on the theoretical error propagation of photon noise through the computation of the color gradient.
H. M. G. Stokman, Th. Gevers, "Automatic Thresholding of Color Edges" in Proc. IS&T 8th Color and Imaging Conf., 2000, pp 178 - 183, https://doi.org/10.2352/CIC.2000.8.1.art00033