1. An apparatus comprising: a machine vision processor programmed to perform the steps of: obtaining a color model image of an expected pattern; obtaining a color run-time image including at least one instance of the pattern; computing a dynamic weight for each of a plurality of color channels in the color model image by calculating a weighting factor for each color channel and subsequently evaluating the weighting factors by computing a variance in contrast; computing a greyscale image of the color model image using the dynamic weights, and a greyscale image of the color run-time image using the dynamic weights; and using the greyscale image of the color model image to determine a pose having at least one non-translational degree of freedom of the expected pattern in the greyscale run-time image of the pattern.