1. A computer-implemented method of segmentation, comprising: receiving at least one difference image; extracting at least one histogram of the difference image; determining a noise component by fitting a symmetric Gaussian distribution to the histogram such that a negative portion of the Gaussian distribution coincides with a negative portion of the histogram; subtracting the noise component from the histogram to generate a probability distribution function; converting the probability distribution function to a cumulative distribution function; and applying the cumulative distribution function to the difference image to generate a probabilistic representation of contrast enhancement (I CE ).