D.C. offset restoration for image scanners

Year	Description
1996	Invention patented by Martin Potucek and George Anthony Hadgis on February 4th, 1996. Abstract: A scanner having a photosensitive scanning array includes a timing generator having (a) a first state wherein pixel clock signals with a predetermined frequency are produced and (b) a second state wherein a D.C. restore clock signal with a frequency that is "N" times slower than the predetermined frequency is produced. The timing generator controls the rate of sampling the scanning array to acquire image data by producing a series of analog image signals containing (a) a video component which is characteristic of a density pattern of a scanned image and (b) a D.C. offset component which is characteristic of the scanning array. The timing generator also controls the rate of sampling the scanning array to acquire an analog signal containing only the D.C. offset component. A D.C. restore calculates an output signal containing only the video component of the series of analog image signals containing the video component and the D.C. offset component. The timing generator is selectively switched to its first state during acquisition of the image data, and to its second state during acquisition of the analog signal containing only the D.C. offset component.
Source: selected by the editor from original sources.

Invention: D.C. offset restoration for image scanners