A best blending function from among a plurality of blending functions is determined. Each of the plurality of blending functions smoothes an overlap region of at least two projected images. The overlap image is captured and a processing unit analyzes the stored overlap image for color value linearity to calculate a first smoothness result. The processing unit analyzes the projection of the first or second image for color value uniformity to calculate a second smoothness result. These smoothness results for one blending function are paired and compared to smoothness result pairs corresponding to other blending functions to determine a best blending function from among those being analyzed.