1. A projection system having at least two projectors, each projector producing a sub-image, wherein the sub-images are projected on a screen to form a composite image and edge portions of the sub-images overlap to form an overlap region, each projector comprising: a light source for producing light; an input circuit for receiving image data signals representing a sub-image and separating the image data signals into separate red, green and blue color component signals and a frame timing signal, the color component signals having pixel brightness data for each pixel of the sub-image; a pixel brightness modification data memory for storing pixel brightness modification data; a pixel brightness modification processor for receiving the color component signals, the frame timing signal, and the pixel brightness modification data and adjusting the pixel brightness data of the color component signals based on the pixel brightness modification data to produce modified color component signals; a display control and formatting circuit for receiving the modified color component signals and producing control signals based on the modified color component signals; at least one SLM device for receiving the control signals and modulating light received from the light source based on the control signals to produce the sub-image; and a projection lens for projecting the sub-image.