Patent ID: 8031941

Claim:
An image display apparatus, comprising: an image projecting unit that projects a projection image on a projection screen; a written image capturing unit that captures a written image of a writing screen that is arranged opposite the projection screen; a written image area extracting unit that extracts a written image area from the captured written image captured by the written image capturing unit; and an image compositing unit that composites the written image area extracted by the written image area extracting unit and the projection image projected by the image projecting unit; and wherein the written image area extracting unit includes an external light value detecting unit that detects an external light value, and an image processing unit that performs an image correction process on the captured written image based on the external light value detected by the external light detecting unit; and wherein said apparatus includes a color distinction unit that performs a color distinction process for distinguishing a color of a pixel of an averaged image obtained by an averaging unit based on one or more color distinction threshold values that are adjustably set according to the external light value detected by the external light value detecting unit; and a color distinction correction unit that performs a color distinction correction process on the image corrected by a brightness correction unit, a noise removal unit, and an outline correction unit, which color distinction correction process involves calculating a rate at which a neighboring pixel of a target pixel within a predetermined correction range of said corrected image is black based on the color-distinguished image obtained by the color distinction unit, determining whether the calculated rate is greater than a predetermined value, and replacing a pixel value of the target pixel of said corrected image with a black pixel value if the calculated rate is greater than the predetermined value.