| 摘要 |
An interactive presentation system uses a presentation computer, a computer-controlled image projector and a projection screen, in which control of the presentation computer is accomplished by using a wireless optical pointer that projects an encoded control cursor onto the projection screen. The projected screen images are monitored by a video camera, and the control cursor is scanned, detected and decoded for emulating various keyboard commands and/or pointing device (mouse, touch pad, track ball) position-dependent cursor operations. The control cursor is reliably detected and its coordinate location is accurately determined on the basis of one or more primary image attributes, for example image intensity and image repetition rate, both of which are independent of monitoring angles and pointing device projection angles, and one or more secondary image attributes, for example image size, color and pattern. Neither of the primary attributes can be masked or obscured by the presence of background screen images or objects. Although the secondary attributes of the control cursor may be identical with the attributes of background images, reliable decoding of a computer command is assured since analysis and decoding of the secondary attributes are conditionally performed only after the control cursor image has been detected and captured (stored in memory for determination of coordinate location) on the basis of one or more of the independent attributes.
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