Apparatus and method for focusing a projected image

摘要

An apparatus and method controlling a projected image (24) is provided. The apparatus (10) includes a detector (16) that tracks a visual pointer (22) appearing on a projection screen (20). The visual pointer (22) is positioned on the image (24) by a viewer. The visual pointer (22) can be generated by a computer cursor, or a light pen or laser pointer (12). The detector (16) generates a position signal indicating the location of the pointer (22). An auto-focus device (18) focuses the portion of the image (24) referenced by the visual pointer (22) as a function of the position signal. To focus the image portion, the auto-focus device (18) positions a projector lens (26) based on the measured image contrast within the selected image portion.