Modern optical engineering pdf

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The earliest optical mice detected movement on modern optical engineering pdf-printed mousepad surfaces. Laser diodes are also used for better resolution and precision. Battery-powered wireless optical mice flash the LED intermittently to save power, and only glow steadily when movement is detected. LED and a four-quadrant infrared sensor to detect grid lines printed with infrared absorbing ink on a special metallic surface.

The optical mouse ultimately sold with the Xerox STAR office computer used an inverted sensor chip packaging approach patented by Lisa M. Cherry of the Xerox Microelectronics Center. The Kirsch and Lyon mouse types had very different behaviors, as the Kirsch mouse used an x-y coordinate system embedded in the pad, and would not work correctly when the pad was rotated, while the Lyon mouse used the x-y coordinate system of the mouse body, as mechanical mice do. This advance enabled the mouse to detect relative motion on a wide variety of surfaces, translating the movement of the mouse into the movement of the cursor and eliminating the need for a special mouse-pad. It worked on almost any surface, and represented a welcome improvement over mechanical mice, which would pick up dirt, track capriciously, invite rough handling, and need to be taken apart and cleaned frequently. A simple binary-image version of digital image correlation was used in the 1980 Lyon optical mouse.

These surfaces, when lit at a grazing angle by a light emitting diode, cast distinct shadows that resemble a hilly terrain lit at sunset. Images of these surfaces are captured in continuous succession and compared with each other to determine how far the mouse has moved. The amount that the edges of one photograph overhang the other represents the offset between the images, and in the case of an optical computer mouse the distance it has moved. Optical mice capture one thousand successive images or more per second. Depending on how fast the mouse is moving, each image will be offset from the previous one by a fraction of a pixel or as many as several pixels.

Optical mice mathematically process these images using cross correlation to calculate how much each successive image is offset from the previous one. 18 pixel array of monochromatic pixels. One refinement would be accelerating the correlation process by using information from previous motions, and another refinement would be preventing deadbands when moving slowly by adding interpolation or frame-skipping. The development of the modern optical mouse at Hewlett-Packard Co. In 1992 William Holland was awarded US Patent 5,089,712 and John Ertel, William Holland, Kent Vincent, Rueiming Jamp, and Richard Baldwin were awarded US Patent 5,149,980 for measuring linear paper advance in a printer by correlating images of paper fibers. Allen, David Beard, Mark T. By describing an optical means that explicitly overcame the limitations of wheels, balls, and rollers used in contemporary computer mice, the optical mouse was anticipated.

Baumgartner, Thomas Hornak, Mark T. Tullis, where surface feature image sensing, image processing, and image correlation was realized by an integrated circuit to produce a position measurement. 600th of an inch, implementation of optical position measurement in computer mice not only benefit from the cost reductions inherent in navigating at lower resolution, but also enjoy the advantage of visual feedback to the user of the cursor position on the computer display. In 2002, Gary Gordon, Derek Knee, Rajeev Badyal and Jason Hartlove were awarded US Patent 6,433,780 for an optical computer mouse that measured position using image correlation. The color of the optical mouse’s LEDs can vary, but red is most common, as red diodes are inexpensive and silicon photodetectors are very sensitive to red light. Other colors are sometimes used, such as the blue LED of the V-Mouse VM-101 illustrated at right. Although invisible to the naked eye, the light produced by this laser mouse is captured as the color purple because CCDs are sensitive to a broader light wavelength range than the human eye.