1. A method comprising: determining a first blend map for a first projector, the first blend map including a first plurality of attenuation factors corresponding to a region of overlap between first and second images projected by the first projector and a second projector, respectively, on a display surface; applying the first blend map to a white level measurement map that includes a plurality of white level measurement values measured from a first plurality of captured images; applying a smoothing function to the white level measurement map to generate a white level target map; and determining a scale map for the first projector from the white level measurement map and the white level target map.