Method and apparatus for forming, projecting and detecting a coded pattern image with a camera and recognition system

Abstract

Method and apparatus () for projecting infrared or near infrared or low intensity visible light from a pen, pointer or other guiding object in the form of a coded pattern image, detectable by a camera and recognition system but invisible, or hardly visible to the user and audience, thus controlling and interacting with a computer () during a presentation, computer supported work and/or other interactive use of a computer, including pointing, selecting, drawing and writing, both distantly () and closely () to the front or rear projection screen or possible other type of display screen, without any distracting visual patterns or spots, while the possible visual feedback to the user and audience can be generated by the computer and display system onto the display screen in a controlled and context-sensitive way. The projected complex images from the positioning device when operating remotely () and when operating closely to the screen (), are created by optical alignment of one or several diffractive optical elements, collimating lens and/or mirrors, and one or more light sources. The light sources can preferably be laser diodes or light emitting diodes. In a preferred embodiment, the light sources are emitting visible, infrared or near-infrared light.