Keystone correction using a part of edges of a screen

摘要

The projector comprises an image forming panel that forms an effective panel image for modulating the light into an image light in an image forming area of a panel surface, and an image capturing unit for capturing a specific projection area wherein the image light corresponding to a specific area in the image forming area is projected. The projector calculates one or more edges of the outside perimeter lines of the screen and of the specific projection area by detecting plural points in a captured image. Based on the detection results, a post-correction image forming area is calculated, and trapezoidal distortion is corrected by forming the effective panel image within the post-correction image forming area. When only three or less of the four edges of the outside perimeter lines of the screen are detected, the projector calculates the post-correction image forming area based on the position and slope of the detected edge within the captured image.