Facsimile and static presentation processing – Facsimile – Picture signal generator
Patent
1994-11-22
1996-07-16
Vu, Kim Yen
Facsimile and static presentation processing
Facsimile
Picture signal generator
358412, H04N 1047
Patent
active
055372260
ABSTRACT:
The present invention is a method and apparatus for restoring or correcting digital images scanned in the presence of mechanical vibration, thereby improving the quality of the output image. In a document scanner, a linear sensor moving relative to a document placed upon a platen is scanned in a manner wherein fluctuations in the nominal scanning velocity are observed. Recognizing that the output of a single photosensor in the linear sensor array is proportional to the integrated irradiance received by the sensor as it scans through an exposure region, when vibratory motion of the sensor array is considered, the actual size of the exposure region is time-varying. The fluctuations or vibrations introduce artifacts such as brightness fluctuation and geometric warping which are eliminated or significantly reduced in accordance with the method of the present invention. Specifically, the instantaneous velocity of the linear sensor array is used to reconstruct an underlying piecewise linear model of the irradiance distribution. That reconstructed image is then resampled under ideal scanning conditions to produce the restored output.
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Loce Robert P.
Wolberg George
Basch Duane C.
Vu Kim Yen
Xerox Corporation
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