Multi-pass document scanner and multi-pass scanning method
An improved document or ID card scanner for imaging documents and decoding coded indicia such as bar codes and magnetic strips is disclosed. The scanner incorporates an internal motor and automatic multi-pass scanning function to quickly and accurately capture all data on a document. During these passes the document is imaged under a number of different lighting conditions and a magnetic strip is read multiple times. The document scanner can perform scans as the document moves in forward and reverse directions; and each scan occurs at a speed optimized to the particular scanning method and direction of the current pass. During the multiple passes, the document is scanned and or read at varying speeds for reliability and for different purposes as detailed herein.
1. A method for multi-pass scanning a document comprising:
mechanically translating a document at a first speed for a first pass within a defined path in a document scanner for a first scan;
mechanically translating said document at a second speed for a second pass within said defined path in the document scanner for a second scan;
mechanically translating said document at a third speed for a third pass within said defined path in the document scanner for recording an image of a surface of said document when illuminated with a first light condition; and
mechanically translating said document at a fourth speed for a fourth pass within said defined path in the document scanner for recording a second image of the surface of said document when illuminated with a second light condition, wherein said document scanner utilizes higher speeds during the first and second passes as compared to the third and the fourth pass.
2. The multi-pass scanning method of claim 1 wherein said document is mechanically translated in a first direction during said first pass and said third pass and said document is translated in a second direction opposite to said first direction during said second pass and said fourth pass.
3. The multi-pass scanning method of claim 2 wherein said first direction is toward a first exit from said document scanner and said second direction is toward a second exit from said document scanner.
4. The multi-pass scanning method of claim 1 further comprising aligning said document within said defined path in a document scanner during said first pass.
5. The multi-pass scanning method of claim 1 further comprising performing a preliminary scan during said first pass.
6. The multi-pass scanning method of claim 5 , wherein said preliminary scan includes measuring a weight and/or a dimension of the document.
7. The multi-pass scanning method of claim 5 , wherein said preliminary scan includes a light transmittance.
8. The multi-pass scanning method of claim 5 , wherein said preliminary scan including:
performing infrared spectroscopy on the document; and
measuring the chemical components of the document from the spectroscopy.
9. The multi-pass scanning method of claim 1 wherein the recording said image is performed by a linear scanner.
10. The multi-pass scanning method of claim 1 further comprising extracting a barcode from said image of a surface of said document.
11. The multi-pass scanning method of claim 1 , further comprising scanning a magnetic strip on said document with a magnetic strip reader configured to the document scanner during said first and/or said second pass.
12. The multi-pass scanning method of claim 11 further comprising mechanically translating a magnetic strip reader from a first magnetic strip reader position during said first pass to a second magnetic strip reader position during said third pass.
13. The multi-pass scanning method of claim 1 wherein said recording an image of a surface of said document comprises simultaneously capturing an image of both sides of said document.
14. The multi-pass scanning method of claim 1 wherein said document is translated from an outside of an external housing of said document scanner to an inside of said external housing during said first pass.
15. The multi-pass scanning method of claim 14 wherein said document partially emerges from said external housing between said first pass and said third pass.
16. A single optical scanner capable of multi-pass scanning a document comprising:
an external housing;
a defined path through said external housing in which a document can be translated;
an access point where a document can be inserted in said defined path from outside said external housing;
a motor or an actuator capable of mechanically translating a document either forward or backward within said defined path;
a magnetic strip reader for scanning a magnetic strip on said document during said document translation along said path;
an image capture device for capturing an image of a side surface of said document during said translating said document ; and
an illumination source capable of illuminating said side surface of said document during said image capture wherein said image capture device is configured to capture both sides of a document during a single image capture.
17. The single optical scanner of claim 16 wherein said image capture device is configured to capture multiple images and wherein said illumination source is capable of illuminating said side surface of said document with a plurality of light conditions during each said image capture.