Vidar Systems Corporation

Cecil V Hornbaker, Iii

Edward W Bindon

Thomas C Driggers

A scanner apparatus using multiple CCD arrays for scanning an image line by line to produce data representative of the image can correct for misalignment of the arrays in the X-axis (scanning) direction and/or Y-axis (feed) direction using a combination of hardware, software, and firmware. To correct for alignment errors in the X-axis direction, the field of view of each of the arrays must overlap. A start pixel is determined for each array based on the degrees of overlap so that a composite scan line of data can be formed from the video image data from each of the arrays. The scan lines are continuously stored in a buffer memory which operates as a ring FIFO buffer. Alignment errors in the Y-axis direction are corrected by software in the host computer which reads separate portions of the scan lines from the buffer memory corresponding to each of the arrays using on read pointers that are set according to the alignment error. The scanner control firmware and software can measure the alignment of the arrays with a simple test target. In addition, the start pixel and read pointers can be changed while displaying the image on a CRT screen so that corrections can be made simultaneously to viewing the image.

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New Carrolton, MD, United States of America

Cecil V Hornbaker, Iii