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US 6,144,467 AGranted
Device and method for improving scanning quality of image scanner
AssigneeMustek Systems Inc.
InventorJenn-Tsair Tsai
Life of this patent
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Abstract
An image scanner having an improved scanning quality is disclosed. Two different color blocks having an interface therebetween are provided on the document platform of the image scanner. The image pickup device passes by the color blocks prior to the document area so that color calibrations and/or error detection can be performed before the scanning operation is performed. By this way, the color data such as the brightness of the obtained image can be compensated, and the deflection rate and/or the amplification error of the image pickup device can be corrected.
Claims20
An image scanner, comprising:
- a scanning platform for placing thereon an object to be scanned, marked thereon:
- a document line for positioning an edge of said object;
- a first elongated color block located in front of said document line along a specific direction;
- and
- a second elongated color block located in front of said document line along said specific direction and having an interface with said first color block;
- and
- a photo-signal processing device passing by said scanning platform from a home position along said specific direction, and performing a scanning operation from a scan start point behind said first and said second color blocks to read image data of said object, and converting said image data of said object into digital data for further processing;
- wherein each of said first and said second elongated color blocks has a length greater than a length of said photo-signal processing device so that said photo-signal processing device detects colors of said first and said second elongated color blocks as standard colors for color calibrations when said photo-signal processing device passes by said first and said second elongated color blocks, and wherein said interface of said first and said second color blocks includes a first reference point and a second reference point whose coordinates are detected according to color changes therearound, a shift from said first reference point to said scan start point is of a predetermined vector which can be used together with said coordinate of said first reference point for determining a position of said scan start point, and a distance between said first and said second reference points is of a constant value which can be used together with said coordinates of said first and said second reference points for determining a deflection rate of a scan track and an amplification error of a scan result.
5 more elements
A method for improving a scanning quality of an image scanner, said image scanner including a scanning platform for placing thereon an object to be scanned, and a photo-signal processing device passing by said scanning platform along a specific direction to perform a scanning operation for said object, said method comprising steps of:
- providing a document line on said scanning platform for positioning said object;
- providing a first color block on said scanning platform, which is located in front of said document line along said specific direction;
- providing a second color block on said scanning platform, which is located in front of said document line along said specific direction and has an interface with said first color block;
- detecting respective coordinates of a first and a second reference points in said interface of said first and said second color blocks according to color changes around said first and said second reference points when said photo-signal processing device passes by said first and said second color blocks along said specific direction;
- determining a scan start point according to said coordinate of said first reference point and a predetermined vector indicative of a shift from said first reference point to said scan start point;
- and
- determining a deflection rate and/or an amplification error of a scanning result according to said coordinates of said first and said second reference points and a predetermined distance between said first and said second reference points for correction of said scan result.
4 more elements
An image scanner, comprising:
- a scanning platform for placing thereon an object to be scanned, marked thereon:
- a document line for positioning a front edge of said object;
- a first color block located in front of said document line along a specific direction;
- and
- a second color block located in front of said document line along a specific direction and having an interface with said first color block;
- and
- a photo-signal processing device passing by said scanning platform from a home position along said specific direction, and performing a scanning operation from a scan start point behind said first and said second color blocks to read image data of said object, and converting said image data of said object into digital data for further processing;
- wherein said interface of said first and said second color blocks includes a first reference point and a second reference point whose coordinates (x1,y1) and (x2,y2), respectively, are detected according to color changes therearound, a shift from said first reference point to said scan start point is of a predetermined vector, which can be used together with said coordinate of said first reference point to determine a position of said scan start point, and a distance L between said first and said second reference points is of a constant value, which can be used together with said coordinates of said first and said second reference points to determine a deflection rate m of a scan track by an equation m=(y2-y1)/(x2-x1), and an amplification error .rho. of a scan result by an equation .rho.=1-[(x2-x1).sup.2 +(y2-y1).sup.2 ].sup.1/2 /L.
5 more elements
Dependencies are inferred from the claim text.