As a photometer measures only a small region in the projected area,it is not suitable for measuring a large-scale display,such as the whole area produced by a projector.Instead of the photometer,the technique used in this research employs raw digital images,which have been recently noticed.Using raw digital images,we accurately measure the luminance distribution of the whole projected area for every pixel and obtain a transfer function of the luminance response for the projector.The transfer function is essential for luminance correction.This paper shows how using raw digital images is a key technique for luminance correction.
