Method and apparatus for transparency scanning with a duplex reflective scanner
View Patent ↗The scanning method of the invention enables a user to scan transparencies with a duplex scanner having a moveable camera, and a mirror or light source associated with the camera on each side of the document path. The scanner, in its normal mode of operation, is a duplex reflective scanner which means the image, per side, is captured by reflecting light from a light source located on the same side of an opaque flat object as the CCD of the camera that captures the image. In order to scan transparencies, a mechanism is provided which allows an opposing camera light source to be aligned (moved at runtime) with the aperture of the camera opposite the opposing camera light source. This allows the light of the opposing camera light source to project through a transparent object while the opposite camera CCD captures an image of the transparency. The opposite camera, which captures the image, has its light source turned off while in the transparent scanning mode.
1. A document scanner for performing a duplex or a transparency scanning operation comprising:
a first camera including a first light source and a first aperture;
an opposed second camera including a second light source and a second aperture, wherein each aperture of each camera is offset from the light source of the oppositely positioned camera during duplex scanning;
a motor for moving said second camera from a first position for duplex scanning to a second position for transparency scanning;
a controller for sending a drive signal to said motor to cause said motor to move said second camera from said first position to said second position when a transparency scanning mode is selected; and
wherein said controller, during movement of the second camera from the first duplex scanning position to the second transparency scanning position, moves the second light source from a first offset position for duplex scanning to a second position aligned with the first aperture of the first camera to enable transparency scanning.
2. A document scanner as in claim 1 wherein said controller switches said first light source off when said transparency scanning mode is selected.
3. A document scanner as in claim 2 wherein said controller activates the first camera and the second light source when said transparency scanning mode is selected.
4. A document scanner as in claim 1 further comprising a sensor wherein the sensor is adapted to detect a patch on a document prior to a transparent document or set of transparent documents to be scanned and send a signal to said controller which switches said scanner from a duplex scanning mode to said transparency scanning mode to enable transparency scanning of the following transparent document or set of transparent documents.
5. A document scanner as in claim 4 , wherein the sensor is adapted to detect a patch on a transparent document prior to a document or set of documents to be scanned in the duplex scanning mode, and send a signal to said controller which switches said scanner from said transparency scanning mode to said duplex scanning mode to enable duplex scanning of the following document or set of documents.
6. A document scanner as in claim 1 further comprising a switch connected to the controller to enable a user to select a simplex, duplex or transparency scanning mode.
7. A document scanner as in claim 6 wherein said controller further sends a drive signal to said motor to cause said motor to move said second camera from said first position or said second position to a third position for simplex scanning when a simplex scanning mode is selected.
8. A document scanner as in claim 7 wherein said controller further switches said first camera off and switches the second camera on while moving the second camera during said simplex scanning mode.
9. A document scanner as in claim 7 further comprising a glass platen to receive a document for simplex scanning wherein the controller sends a drive signal to the motor to cause said motor to move said second camera from said first position or said second position along a surface of said platen and activates said second camera when said simplex scanning mode is selected.
10. A document scanner for performing a duplex or a transparency scanning operation comprising:
a first camera having a first light source;
an opposed second camera including a second light source and a second aperture, wherein each aperture of each camera is offset from the light source of the oppositely positioned camera during duplex scanning;
a motor for moving said second camera from a first position for duplex scanning to a second position for transparency scanning and for tilting said second light source from a first position for duplex scanning to a second position for transparency scanning;
a controller for sending a drive signal to said motor to cause said motor to move said second camera from said first position to said second position and to move said second light source from said first position for duplex scanning to said second position for transparency scanning when a transparency scanning mode is selected; and
wherein said controller, during movement of the second camera from the first duplex scanning position to the second transparency scanning position, moves the second light source from a first offset position for duplex scanning to a second position aligned with the first aperture of the first camera to enable transparency scanning.
11. A document scanner as in claim 10 wherein said controller switches said first light source off when said transparency scanning mode is selected.
12. A document scanner as in claim 11 wherein said controller activates the first camera and the second light source when said transparency scanning mode is selected.
13. A document scanner as in claim 10 further comprising a sensor wherein the sensor is adapted to detect a patch on a document prior to a transparent document or set of transparent documents to be scanned and send a signal to said controller which switches said scanner from a duplex scanning mode to said transparency scanning mode to enable transparency scanning of the following transparent document or set of transparent documents.
14. A document scanner as in claim 10 further comprising a switch connected to the controller to enable a user to select a simplex, duplex or transparency scanning mode.
15. A document scanner as in claim 14 wherein said controller further sends a drive signal to said motor to cause said motor to move said second camera from said first position for duplex scanning or said second position for transparency scanning to a third position for simplex scanning and to tilt the second light source when in the second position for transparency scanning to a third position for simplex scanning when simplex scanning is selected.
16. A document scanner as in claim 15 wherein said controller further switches said first camera off and activates the second camera when said simplex scanning mode is to be performed.
17. A document scanner as in claim 15 further comprising a glass platen to receive a document for simplex scanning wherein the controller sends a drive signal to the motor to cause said motor to move said second camera from said first position for duplex scanning or said second position for transparency scanning along a surface of said platen and activates said second camera when said simplex scanning mode is selected.