Scanning apparatus using multiple CCD arrays and related method
First Claim
1. An apparatus for scanning an image line by line to produce data representative of the image comprising:
- a plurality of linear arrays, each of the arrays having a plurality of photosensitive pixel elements arranged in succession along a linear axis of the array;
means for moving the image relative to the arrays;
means for supporting the arrays in position to scan the image with the linear axis of the arrays extending substantially perpendicular to the direction of movement of the image relative to the arrays;
means for determining a starting pixel element for each array;
means for reading video image data from each of the arrays beginning at the starting pixel element for each array and ending a predetermined number of pixel elements after the starting pixel element, said reading means comprising;
means for providing to each of the arrays a number of clock pulses corresponding to the starting pixel element for each array in order to reach the video image data,memory means for storing in sequential memory locations flag data corresponding to the predetermined number of pixel elements for each array,counter means for sequentially addressing the memory means,means for providing clock pulses to each of the arrays in response to the flag data read from the memory to transport the video image data out of the arrays; and
means for forming a composite scan line of data representative of a single line of the image from the video image data read from each of the arrays.
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Accused Products
Abstract
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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Citations
27 Claims
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1. An apparatus for scanning an image line by line to produce data representative of the image comprising:
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a plurality of linear arrays, each of the arrays having a plurality of photosensitive pixel elements arranged in succession along a linear axis of the array; means for moving the image relative to the arrays; means for supporting the arrays in position to scan the image with the linear axis of the arrays extending substantially perpendicular to the direction of movement of the image relative to the arrays; means for determining a starting pixel element for each array; means for reading video image data from each of the arrays beginning at the starting pixel element for each array and ending a predetermined number of pixel elements after the starting pixel element, said reading means comprising; means for providing to each of the arrays a number of clock pulses corresponding to the starting pixel element for each array in order to reach the video image data, memory means for storing in sequential memory locations flag data corresponding to the predetermined number of pixel elements for each array, counter means for sequentially addressing the memory means, means for providing clock pulses to each of the arrays in response to the flag data read from the memory to transport the video image data out of the arrays; and means for forming a composite scan line of data representative of a single line of the image from the video image data read from each of the arrays. - View Dependent Claims (2, 3)
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4. An apparatus for scanning an image line by line to produce data representative of the image comprising:
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a plurality of linear arrays, each of the arrays having a plurality of photosensitive pixel elements arranged in succession along a linear axis of the array; means for moving the image relative to the arrays; means for supporting the arrays in position to scan the image with the linear axis of the arrays extending substantially perpendicular to the direction of movement of the image relative to the arrays; means for reading video image data from each of the arrays; means for forming scan lines of data from the video image data read from each of the arrays; memory buffer means for storing the scan lines of data in sequential memory locations; means for determining starting read pointers corresponding to each array for reading from the memory buffer means separate portions of the scan lines of data corresponding to the video image data read from each of the arrays; and means for reading from the memory buffer means the separate portions of the scan lines of data to form a composite scan line of data representative of a single line of the image. - View Dependent Claims (5)
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6. An apparatus for scanning an image line by line to produce data representative of the image comprising:
- `a plurality of linear arrays, each of the arrays having a plurality of photosensitive pixel elements arranged in succession along a linear axis of the array;
means for moving the image relative to the arrays; means for supporting the arrays in position to scan the image with the linear axis of the arrays extending substantially perpendicular to the direction of movement of the image relative to the arrays; means for determining a starting pixel element for each array; means for reading video image data from each of the arrays beginning at the starting pixel element for each array and ending a predetermined number of pixel elements after the starting pixel element; means for forming scan lines of data from the video image data read from each of the arrays; memory buffer means for storing the scan lines of data in sequential memory locations; means for determining starting read pointers corresponding to each array for reading from the memory buffer means separate portions of the scan lines of data corresponding to the video image data read from each of the arrays; and means for reading from the memory buffer means the separate portions of the scan lines of data to form a composite scan line of data representative of a single line of the image. - View Dependent Claims (7, 8, 9)
- `a plurality of linear arrays, each of the arrays having a plurality of photosensitive pixel elements arranged in succession along a linear axis of the array;
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10. In an apparatus for scanning an image line by line to produce data representative of the image, the apparatus including a plurality of linear arrays, each of the arrays having a plurality of photosensitive pixel elements arranged in succession along a linear axis of the array, wherein the image moves relative to the arrays, and wherein the arrays are supported in position to scan the image with the linear axis of the arrays extending substantially perpendicular to the direction of movement of the image relative to the arrays, a method of forming a composite scan line of data representative of a single line of the image comprising the steps of:
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determining a starting pixel element for each array; reading video image data from each of the arrays beginning at the starting pixel element for each array and ending a predetermined number of pixel elements after the starting pixel element; providing to each of the arrays a number of clock pulses corresponding to the starting pixel element for each array in order to reach the video image data; sequentially addressing a random access memory in which flag data corresponding to the predetermined number of pixel elements for each array has been stored in sequential memory locations; providing clock pulses to each of the arrays in response to the flag data read from the memory to transport the video image data out of the arrays; and forming the composite scan line of data from the video image data read from each of the arrays. - View Dependent Claims (11, 12)
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13. In an apparatus for scanning an image line by line to produce data representative of the image, the apparatus including a plurality of linear arrays, each of the arrays having a plurality of photosensitive pixel elements arranged in succession along a linear axis of the array, wherein the image moves relative to the arrays, and wherein the arrays are supported in position to scan the image with the linear axis of the arrays extending substantially perpendicular to the direction of movement of the image relative to the arrays, a method of forming a composite scan line of data representative of a single line of the image comprising the steps of:
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reading video image data from each of the arrays; forming scan lines of data from the video image data read from each of the arrays; storing the scan lines of data in sequential memory locations in a memory buffer; determining starting read pointers corresponding to each array for reading from the memory buffer separate portions of the scan lines of data corresponding to the video image data read from each of the arrays; and reading from the memory buffer the separate portions of the scan lines of data to form the composite scan line of data. - View Dependent Claims (14)
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15. In an apparatus for scanning an image line by line to produce data representative of the image, the apparatus including a plurality of linear arrays, each of the arrays having a plurality of photosensitive pixel elements arranged in succession along a linear axis of the array, wherein the image moves relative to the arrays, and wherein the arrays are supported in position to scan the image with the linear axis of the arrays extending substantially perpendicular to the direction of movement of the image relative to the arrays, a method of forming a composite scan line of data representative of a single line of the image comprising the steps of:
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determining a starting pixel element for each array; reading video image data from each of the arrays beginning at the starting pixel element for each array and ending a predetermined number of pixel elements after the starting pixel element; and forming scan lines of data from the video image data read from each of the arrays; storing the scan lines of data in sequential memory locations in a memory buffer; determining starting read pointers corresponding to each array for reading from the memory buffer separate portions of the scan lines of data corresponding to the video image data read from each of the arrays; and reading from the memory buffer the separate portions of the scan lines of data to form the composite scan line of data. - View Dependent Claims (16, 17, 18, 19)
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20. An apparatus for scanning an image line by line to produce data representative of the image comprising:
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a plurality of linear arrays, each of the arrays having a plurality of photosensitive pixel elements arranged in succession along a linear axis of the array; means for moving the image relative to the arrays; means for supporting the arrays in position to scan the image with the linear axis of the arrays extending substantially perpendicular to the direction of movement of the image relative to the arrays; optical calibration means for providing a target image to the arrays; means for reading video image data from each of the arrays; means for automatically determining an error value from video image data corresponding to the target image for correcting a stitch error due to physical positioning of the arrays relative to each other, wherein the error value corresponds to an offset between the arrays in the direction of movement of the image; and means for forming scan lines of data from the video image data read from each of the arrays. - View Dependent Claims (21, 22, 23)
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24. In an apparatus for scanning an image line by line to produce data representative of the image, the apparatus including a plurality of linear arrays, each of the arrays having a plurality of photosensitive pixel elements arranged in succession along a linear axis of the array, wherein the image moves relative to the arrays, and wherein the arrays are supported in position to scan the image with the linear axis of the arrays extending substantially perpendicular to the direction of movement of the image relative to the arrays, a method of forming a composite scan line of data representative of a single line of the image comprising the steps of:
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providing a target image to the arrays; reading video image data from each of the arrays; automatically determining an error value from video image data corresponding to the target image for correcting a stitch error due to physical positioning of the arrays relative to each other, wherein the error value corresponds to an offset between the arrays in the direction of movement of the image; and forming scan lines of data from the video image data read from each of the arrays. - View Dependent Claims (25, 26, 27)
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Specification