Fingerprint scanning with optical navigation
View Patent ↗An optical navigation subsystem may be used when obtaining a candidate fingerprint for a mobile communication device (e.g., for authentication purposes). To accommodate such use of the optical navigation subsystem, the optical navigation subsystem may be adapted to automatically adjust a processed image sensor window from a first set of window dimensions (e.g., suitable for optical navigation) to a second set of window dimensions (e.g., suitable for fingerprint capture). Alternatively, a single, static set of window dimension may be employed in conjunction with stitching algorithms, or other methods suitable for forming candidate fingerprint images by combining a plurality of images obtained using the static set of window dimension.
1. A method of handling images in a wireless device having an image processor coupled to an image sensor, the method comprising:
transmitting windowing instructions to the image sensor, the windowing instructions specifying at least one of: (a) a size for a window on the image sensor, inside which window images are to be captured, and (b) a placement of a window on the image sensor, inside which window images are to be captured;
receiving, from the image sensor, a digital image of a finger captured at the image sensor inside the window defined by the windowing instructions; and
processing the digital image in a context of a plurality of previously received digital images to determine a finger motion indication.
2. The method of claim 1 wherein the finger motion indication comprises an indication of a position change in a first linear direction.
3. The method of claim 2 wherein the finger motion indication comprises an indication of a position change in a second linear direction.
4. The method of claim 1 wherein the finger motion indication comprises an indication of a rate of position change.
5. A biometric and optical navigation subsystem comprising:
an image sensor;
a processor adapted to:
transmit windowing instructions to the image sensor, the windowing instructions specifying at least one of: (a) a size for a window on the image sensor, inside which window images are to be captured, and (b) a placement of a window on the image sensor, inside which window images are to be captured;
receive, from the image sensor, a digital image of a finger captured at the image sensor; and
process the digital image in a context of a plurality of previously received digital images to determine a finger motion indication.
6. The biometric and optical navigation subsystem of claim 5 further comprising:
a windowing module interposing the processor and the image sensor, the windowing module adapted to:
receive instructions from the processor and, based on the instructions, control the image sensor.
7. The biometric and optical navigation subsystem of claim 5 further comprising a communication interface for managing communication with an image processor.
8. The biometric and optical navigation subsystem of claim 5 wherein the communication interface comprises an Inter-Integrated Circuit bus interface.
9. The biometric and optical navigation subsystem of claim 5 wherein the windowing instructions specify a frame rate for the image sensor on which images are to be captured.
10. A non-transitory computer readable medium containing computer-executable instructions that, when performed by a processor for a photography subsystem, cause the processor to:
transmit windowing instructions to an image sensor, the windowing instructions specifying at least one of: (a) a size for a window on the image sensor, inside which window images are to be captured, and (b) a placement of a window on the image sensor, inside which window images are to be captured;
receive, from the image sensor, a digital image of a finger captured by an image sensor; and
process the digital image in a context of a plurality of previously received digital images to determine a finger motion indication.
11. The non-transitory computer readable medium of claim 10 wherein the finger motion indication comprises an indication of a position change in a first linear direction.
12. The non-transitory computer readable medium of claim 11 wherein the finger motion indication comprises an indication of a position change in a second linear direction.
13. The non-transitory computer readable medium of claim 10 wherein the finger motion indication comprises an indication of a rate of position change.
14. The non-transitory computer readable medium of claim 10 wherein the instructions further cause the processor to receive windowing instructions from an image processor and transmit the windowing instructions to a suitable module.