Method for examining a value document, and means for carrying out the method
There is described a method for examining a value document while employing a digital image of the value document which comprises pixels, wherein the image is examined for the presence of at least one irregularity relating to a pre-specified property of the value document, when such an irregularity is found an examination region representing the irregularity is fixed in dependence on the size and/or position and/or form of the irregularity in the image, and for checking the irregularity only a part of those pixels of the digital image that correspond to the examination region is employed.
1. A method for examining a value document while employing a digital image of the value document which comprises pixels,
wherein the image is examined for the presence of at least one irregularity relating to a pre-specified property of the value document,
when such an irregularity is found an examination region representing the irregularity is fixed in dependence on the size and/or position and/or form of the irregularity in the image, and the irregularity is checked,
wherein of pixels of the digital image that correspond to the examination region only a part is employed in checking the irregularity, and
wherein the part of the pixels of the digital image employed in checking the irregularity forms an image of the examination region that is reduced in its pixel resolution; and
wherein the pixels of the digital image correspond to locations on a grid, and the part of the pixels that is employed upon checking lies on a subgrid of the grid, the subgrid having a pre-specified grid constant that is greater than that of the grid.
2. The method according to claim 1 , wherein the pre-specified property of the value document is its form.
3. The method according to claim 1 , wherein upon checking the irregularity only a part of those pixels that correspond to the examination region is employed only when the size of the examination region or the number of pixels that represent the examination region exceeds a pre-specified limiting value.
4. The method according to claim 1 , wherein it is established upon checking the irregularity whether the irregularity corresponds to one of at least two possible value-document defects.
5. The method according to claim 1 , wherein the digital image of the value document is captured while employing an optical sensor.
6. A computer program with program code upon whose execution by means of at least one processor a method according to claim 1 is executed.
7. A non-transitory computer readable medium on which a computer program according to claim 6 is stored.
8. An examination device for examining a value document having an optical sensor for capturing a digital image of the value document, and
an evaluation device which is configured for carrying out a method according to claim 1 while employing a digital image captured by means of the optical sensor.
9. The examination device according to claim 8 , wherein the evaluation device has at least one processor and a storage in which a computer program wherein the digital image of the value document is captured while employing an optical sensor is stored, so that upon execution of the program code of the computer program by means of the processor the a method for examining a value document is carried out while employing a digital image of the value document which comprises pixels, wherein the image is examined for the presence of at least one irregularity relating to a pre-specified property of the value document, when such an irregularity is found an examination region representing the irregularity is fixed in dependence on the size and/or position and/or form of the irregularity in the image, and the irregularity is checked, wherein only a part of those pixels of the digital image that correspond to the examination region is employed.
10. An apparatus for processing value documents having
a feeding device for feeding single or singled value documents to be processed,
an output device having at least one output portion for receiving processed value documents,
a transport device for transporting single or singled value documents from the feeding device to the output device, and
an examination apparatus according to claim 8 ,
wherein the optical sensor of the examination device is configured and adapted for capturing a digital image of the value document while it is being transported by means of the transport device.
11. The method according to claim 1 , wherein the at least one irregularity comprises a dog's-ear, a folded portion, or a detached portion.
12. The method according to claim 1 , wherein the pixel resolution of the examination region is reduced by a pre-specified factor.
13. The method according to claim 1 , wherein the examination region is fixed in dependence on a position of bending points along edges of the value document and the direction of portions of the edges that are separated by the bending points.
14. A method for examining a value document while employing a digital image of the value document which comprises pixels,
wherein the image is examined for the presence of at least one irregularity relating to a pre-specified property of the value document,
when such an irregularity is found an examination region representing the irregularity is fixed in dependence on the size and/or position and/or form of the irregularity in the image, and the irregularity is checked,
wherein of pixels of the digital image that correspond to the examination region only a part is employed in checking the irregularity,
wherein the irregularity is checked by a comparison of an intensity and location of the part of the pixels of the examination region with a threshold intensity determined from a reference region outside of the examination region,
wherein the examination region is fixed in dependence on a position of bending points along edges of the value document and the direction of portions of the edges that are separated by the bending points.