Hewlett-Packard Company

Wayne G Phillips

David Douglas Bohn

Paul M Hubel

Dan S Johnson

Kenneth D Gennetten

An optical scanning device is disclosed that generates data representative of a color image of an object using only one linear photosensor array. Image data corresponding to two or more color components is collected by making multiple incremental, reciprocal displacements of a scanning head with a different filter or other color selection mechanism in place during different incremental displacements. By traversing the scanned object in a series of reciprocal movements, color component data corresponding to relatively small portions of the scanned object is sequentially collected in and then removed from dynamic memory. As this data from each path segment is removed from dynamic memory, it is processed to place it in a correlated form representative of a polychromatic image of that path segment and is then stored in an ordered array in another, typically longer term, memory device such as a hard disk.

Color optical scanner with single linear array

A sensor assembly and an optical image color scanner using the sensor assembly. The sensor assembly is of the type having three separate rows of optical sensors. Two of the three sensor rows have color filters and one is unfiltered (receptive to white light). For gray scale scanning, only the unfiltered (white) sensor row is used, thereby maximizing the speed of gray scale scanning. For color scanning, three color values are computed as a linear transformation of values from the two filtered and one unfiltered values. The linear transformation may be as simple as subtracting signals from the two filtered sensor rows from the signal from the unfiltered (white) sensor row. For color scanning, memory buffers are required for two of the three sensor output signals. For highest accuracy in color scanning, the exposure time for the white sensor row is reduced relative to the exposure time for the two filtered sensor rows. An optional white channel bandpass filter (passing all wavelengths within the human visual range and rejecting wavelengths outside the human visual range) provides improved accuracy if the light source has significant wavelengths outside the human visual range.

Sensor assembly providing gray scale and color for an optical image

A method of scanning an object at a predetermined resolution along the scanning direction with color scanner apparatus having M linear photosensors positioned in parallel, spaced-apart relation and being exposed for a predetermined exposure time, may comprise the steps of calculating an exposure delay time for each of (M-1) slave linear photosensors. Then, at a start scan time, a master linear photosensor is exposed to light from the illuminated scan line for the predetermined exposure time. However, the slave linear photosensors are not necessarily exposed at the start scan time. Instead, the first exposure for each of the slave linear photosensors is delayed for a time equivalent to the exposure delay time calculated for each respective slave linear photosensor.

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Loveland, CO, United States of America

Wayne G Phillips