Patent ID: 7187391

Claim:
A projection display apparatus that projects images onto a screen responsive to given image data, comprising: an image extraction section that extracts at least a portion of given first image data as an extraction image; an extraction image memory that stores extraction image data representing the extraction image; an image overlay section that generates overlaid image data by superimposing the extraction image on original image represented by given second image data and provides the overlaid image data as an electrical signal at an image overlay section output; a light modulation unit that is connected to the image overlay section output and driven pixel by pixel in response to the overlaid image data contained in the electrical signal received from the image overlay section output; and an optical system for projecting onto the screen the overlaid image obtained by the light modulation unit, wherein the extraction image memory stores a plurality of extraction image data representing a plurality of extraction images, and the image overlay section superimposes at least one extraction image selected among the plurality of extraction images at each specified position on the original image, wherein the image overlay section comprises, a synthesizer section that generates the overlaid image data by synthesizing the given second image data and the extraction image data read out from the extraction image memory, and a frame memory that stores the overlaid image data, the frame memory having at least a memory area corresponding to all the pixels of the light modulation unit, the overlaid image data read out of the frame memory being supplied to the light modulation unit, and wherein the synthesizer section comprises, a multiplier section that multiplies the second image data and the extraction image data by respective coefficients on a pixel by pixel basis, and an adder section that adds the multiplied second image data and the extraction image data on a pixel by pixel basis.