Method and apparatus for fingerprint motion tracking using an in-line array

• US 20100284565A1
• Filed: 09/11/2006
• Published: 11/11/2010
• Est. Priority Date: 09/11/2006
• Status: Active Grant

• Current Assignee: Synaptics Incorporated
• Original Assignee: Validity Sensors Incorporated (Synaptics Incorporated)
• Inventors: Geoffroy, David Joseph, Benkley, Fred George
• Granted Patent: US 8,447,077 B2
• Time in Patent Office: Days
• US Class Current: 382/103
• CPC Class Codes: G06T 7/248 involving reference images or patches
• CPC Class Codes: G06V 40/1335 Combining adjacent partial images (e.g. slices) to create a composite input or reference pattern; Tracking a sweeping finger movement

Abstract

A fingerprint motion tracking method and system is provided for sensing features of a fingerprint along an axis of finger motion, where a linear sensor array has a plurality of substantially contiguous sensing elements configured to capture substantially contiguous overlapping segments of image data. A processing element is configured to receive segments of image data captured by the linear sensor array and to generate fingerprint motion data. Multiple sensor arrays may be included for generating directional data. The motion tracking data may be used in conjunction with a fingerprint image sensor to reconstruct a fingerprint image using the motion data either alone or together with the directional data.

Claims

1. A fingerprint motion tracking system, comprising:

a linear sensor array configured to sense features of a fingerprint along an axis of finger motion, the linear sensor array including a plurality of substantially contiguous sensing elements configured to capture substantially contiguous overlapping segments of image data; and

a processing element configured to receive the segments of image data captured by the linear sensor array and to generate fingerprint motion data.

2. A system according to claim 1, wherein the linear sensor array is configured to repeatedly sense at least two substantially contiguous segments of fingerprint data, and wherein the processing element is configured to generate fingerprint motion data based on at least two sensed contiguous segments of fingerprint data.

3. A system according to claim 1, wherein the linear sensor array is configured to repeatedly sense substantially contiguous segments of fingerprint data, and wherein the processing element is configured to generate fingerprint motion data based on at least two sensed contiguous segments of fingerprint data.

4. A system according to claim 3, the system further comprising a fingerprint image sensor configured to sense portions of a fingerprint image to be reconstructed into a full fingerprint image using fingerprint motion data.

5. A system according to claim 1, wherein the linear sensor array is configured to sense a first set of features of a fingerprint along an axis of finger motion and to generate a first set of image data captured by a plurality of substantially contiguous pixels of the linear sensor array and is also configured to subsequently sense a second set of features of the fingerprint along an axis of finger motion and to generate a second set of image data captured by a plurality of substantially contiguous pixels of the linear sensor array, and wherein the processing element is configured to compare first and second sets of image data to determine the distance traveled by the fingerprint over a time interval.

6. A system according to claim 1, wherein the linear sensor array is configured to sense a first set of features of a fingerprint along an axis of finger motion and to generate a first set of image data captured by a plurality of substantially contiguous pixels of the sensor array and is also configured to subsequently sense a second set of features of the fingerprint along an axis of finger motion and to generate a second set of image data captured by a plurality of substantially contiguous pixels of the sensor array, and wherein the processing element is configured to compare first and second sets of image data to determine the velocity of the fingerprint moving across the sensor array.

7. A system according to claim 1, further comprising another linear sensor array configured to sense features of a fingerprint and to generate directional image data captured by a plurality of substantially contiguous pixels, wherein the processing element is configured to produce navigation data using the fingerprint motion data to assemble contiguous image portions aligned along a second line of motion.

8. A system according to claim 1, further comprising another linear sensor array aligned along another axis of finger motion and configured to sense features of a fingerprint and to generate directional image data captured by a plurality of substantially contiguous pixels.

9. A system according to claim 8, further comprising a sensor matrix configured to capture portions of a fingerprint image, wherein the processing element is further configured to reconstruct a fingerprint image using the directional image data.

10. A system according to claim 1, further comprising another linear sensor array aligned along another axis of finger motion and configured to sense features of a fingerprint and to generate directional image data and image motion data captured by a plurality of substantially contiguous pixels.

11. A system according to claim 10, further comprising a sensor matrix configured to capture portions of a fingerprint image, wherein the processing element is further configured to reconstruct a fingerprint image using the image motion data and directional image data.

12. A system according to claim 1, further comprising a plurality of linear sensor arrays configured to sense features of a fingerprint and to generate directional image data captured by a plurality of substantially contiguous pixels, wherein the processing element is configured to produce navigation data using the fingerprint motion data to assemble contiguous image portions.

13. A system according to claim 1, further comprising a fingerprint sensor matrix configured to sense and capture image portions of a fingerprint, wherein the processing element is configured to reconstruct a fingerprint image using the fingerprint motion data to assemble contiguous image portions.

14. A system according to claim 1, further comprising another linear sensor array configured to sense features of a fingerprint and to generate directional image data captured by a plurality of substantially contiguous pixels, and a fingerprint sensor matrix configured to sense and capture image portions of a fingerprint, wherein the processing element is configured to reconstruct a fingerprint image using the fingerprint motion data to assemble contiguous image portions.

15. A system according to claim 1, wherein the fingerprint motion data includes data that indicates the distance traveled by a fingerprint.

16. A system according to claim 8, wherein the fingerprint motion data includes data that indicates the direction traveled by a fingerprint.

17. A system according to claim 8, wherein the fingerprint motion data includes data that indicates the distance and direction traveled by a fingerprint.

18. A system according to claim 1, wherein the fingerprint motion data includes data that indicates the velocity of a fingerprint relative to the linear sensor array.

19. A system according to claim 8, wherein the fingerprint motion data includes data that indicates the velocity and direction of a fingerprint relative to the linear sensor array.

20. A method of determining motion of a fingerprint surface with respect to a sensor surface, comprising:

sensing at least two consecutive arrays of a fingerprint image features located along an axis of motion of the fingerprint surface with respect to the sensor surface;

storing digital data corresponding to the arrays of a fingerprint image features sensed by a plurality of sensing elements; and

processing the digital data to generate fingerprint motion data.

21. A method according to claim 20, further comprising:

comparing digital data of a series of fingerprint image features with a subsequently sensed series of fingerprint image features; and

determining an amount of pixel shift between the series of fingerprint image features and the subsequently sensed series of fingerprint image features.

22. A method according to claim 21, further comprising:

estimating the distance traveled by the fingerprint surface with respect to the sensor surface by multiplying the pixel shift detected between subsequent images times the physical distance of the image pixels in the sensor; and

computing the velocity of the fingerprint surface with respect to the sensor surface by dividing the estimated distance by the time expended between the sensing of the fingerprint image features and the subsequently sensed fingerprint image features.

31. A system according to claim 20, further comprising sensing portions of a fingerprint image to be reconstructed into a full fingerprint image using fingerprint motion data.

23. A processor-implemented method of determining motion of a fingerprint surface with respect to a sensor surface, comprising:

collecting a time sequence of image samples from a linear sensory array, wherein each sample has a series of pixel values corresponding to substantially contiguous fingerprint image features;

generating a list of similarity match scores by comparing each image sample with a previous sample;

determining a pixel shift of two image samples having the highest similarity match score;

estimating the distance traveled by multiplying the number of pixels in an image sample times the physical distance between pixels; and

computing a velocity estimate by dividing the estimated distance by the time expended between collecting the two samples with the highest match score.

24. A processor-implemented method of determining motion of a fingerprint surface with respect to a sensor surface, comprising:

collecting a time sequence of images values from each of a plurality of linear image sensor arrays;

generating separate lists of similarity match scores for each linear image sensor array by comparing successively shifted versions of each image sample with a previous sample;

determining which linear sensor array produced the highest similarity match score to represent the principal axis of motion;

determining a pixel shift of the linear sensor array that has the highest similarity match score;

estimating the distance traveled along the principal axis by multiplying the number of pixels times the physical distance between pixels; and

computing the velocity of the fingerprint surface with respect to the sensor surface and producing a velocity value.

25. A method according to claim 24, further comprising:

determining a linear sensor array adjacent to the principal axis that had the next highest similarity score to represent a secondary axis of motion;

determining a pixel shift of the secondary axis with the highest similarity match score; and

if the pixel shift of the pixels on the secondary axis is less than the pixel shift of the pixels on the primary axis, computing the final velocity and direction as a vector sum of the pixels on the secondary axis and the pixels on the primary axis.

26. A system for determining the motion of a fingerprint surface with respect to a sensor surface, comprising:

means for sensing at least two substantially contiguous overlapping arrays of fingerprint image features located along an axis of motion of the fingerprint surface with respect to the sensor surface;

means for generating digital data representing the two substantially contiguous overlapping arrays of fingerprint image features; and

means for processing the digital data to generate fingerprint motion data.

27. A system according to claim 26, further comprising means for repeatedly sensing at least two substantially contiguous segments of fingerprint data, and means for generating motion data based on at least two sensed contiguous segments of fingerprint data.

28. A system according to claim 26, further comprising means for sensing a plurality of image arrays of a fingerprint and means for generating directional image data captured by a plurality of substantially contiguous pixels, and means for producing navigation data using the directional image data.

29. A system according to claim 26, further comprising:

means for collecting a time sequence of images values from each of a plurality of linear image sensor arrays;

means for generating separate lists of similarity match scores for each linear image sensor array by comparing successively shifted versions of each image sample with a previous sample;

means for determining which linear sensor array produced the highest similarity match score to represent the principal axis of motion;

means for determining a pixel shift of the linear sensor array that has the highest similarity match score;

means for estimating the distance traveled along the principal axis by multiplying the number of pixels times the physical distance between pixels; and

means computing the velocity of the fingerprint surface with respect to the sensor surface.

means for comparing the generated data with data representing a subsequently sensed series of fingerprint image features;

means for determining the amount of shift between the series of fingerprint image features and the subsequently sensed series of fingerprint image features; and

means for generating fingerprint motion and direction data.

30. A system according to claim 29, further comprising means for sensing portions of a fingerprint image to be reconstructed into a full fingerprint image using fingerprint motion data.

32. A system according to claim 29, further comprising sensing portions of a fingerprint image to be reconstructed into a full fingerprint image using fingerprint motion and direction data.