mmUbyte converts a BIT, UBYTE, USHORT or DOUBLE image X into an UBYTE image following one of three conversion methods:
METHOD = 'CAST': copy and truncate the pixel values.
METHOD = 'NORM': normalize the result such that the minimum value of the image is assigned the value MIN and the maximum pixel value of the image is assigned the value MAX. This method is not applied to binary images
METHOD = 'WINLEV': enhance the pixels between MIN and MAX. values less or equal MIN are assigned 0, values larger or equal MAX are assigned 255. The other values are scaled accordingly.