1. A method for processing a digital image, the method comprising: acquiring a digital first image of a biological object; estimating a foreground region from the first image relating to the biological object, wherein the estimating of a foreground region includes defining an initial foreground region as that region containing those pixels of the first image meeting a first criterion; estimating a background region from the first image relating to other than the biological object, wherein the estimating a background region includes defining the background region as that region containing those pixels of the first image meeting a second criterion; and by using the first image, the estimated foreground region and the estimated background region, calculating a transition region disposed between the foreground region and the background region by a gradient constrained hysteresis threshold method, wherein pixels of the transition region meet a third criterion; wherein the estimated foreground region, the estimated background region, and the calculated transition region, each comprise a separate set of pixels that may each be processed separately for suppressing pixel intensities in the estimated background region and improving image quality; iteratively calculating incremental transition regions, each having an incrementally larger gradient tolerance value, until a gradient tolerance value threshold is met or exceeded, wherein: each incremental transition region is calculated to be that region containing pixels connected to a pixel of a previously calculated incremental transition region, having an intensity greater than the second threshold, and having a gradient magnitude that is within the incrementally larger gradient tolerance value of the gradient magnitude of the incremental transition region pixel to which it is connected; and, generating a second image of the biological object when the gradient tolerance value threshold is met or exceeded.