System for and method of image reconstruction with dual line scanner using line counts

• US 8,594,393 B2
• Filed: 01/26/2011
• Issued: 11/26/2013
• Est. Priority Date: 01/26/2011
• Status: Active Grant

• Current Assignee: Synaptics Incorporated
• Original Assignee: Validity Sensors
• Inventors: Russo, Anthony
• Primary Examiner(s): Bali, Vikkram
• Application Number:
  US13/014,389
• Publication Number:
  US 20120189172A1
• Time in Patent Office: 1,035 Days
• Field of Search: None
• US Class Current: 382/124
• 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 scanning and image reconstruction system and method including a fingerprint scanner providing a first scan line and a second scan line separated by a line separation distance in a scanning direction. The system includes an image reconstruction module accumulating scan lines including at least the first scan line and the second scan line over a time period t. The image reconstruction module a value for decimation (t) necessary to produce a selected y axis resolution in the scanning direction based at least in part on (line count(t)/line separation distance)* a selected y resolution, where line count(t) is the number of lines accumulated in time t, and decimation(t) indicates of whether the line count(t) is greater than or less than the number of lines accumulated as a function of the time period t that will result in a selected reconstructed image y resolution in the scanning direction.

Claims

1. A fingerprint scanning and image reconstruction system comprising:

a fingerprint scanner providing a first scan line and a second scan line separated by a line separation distance in a scanning direction; and

an image reconstruction module in communication with the fingerprint scanner, the image reconstruction module receiving scan lines including at least the first scan line and the second scan line, the image reconstruction module accumulating scan lines over a time period t;

the image reconstruction module determining a value for decimation (t) necessary to produce a selected y axis resolution in the scanning direction based at least in part on (line count(t) divided by line separation distance) times the selected y resolution, where line count(t) is the number of lines accumulated as a function of the time period t, and

decimation(t) is a ratio indicative of whether the line count(t) is greater than or less than the number of lines accumulated as a function of the time period t that will result in the selected reconstructed image y resolution in the scanning direction.

2. The system of claim 1 wherein the image reconstruction module is adapted to remove scan lines from a reconstructed image when the decimation(t) ratio is greater than 1 and to add interpolated scan lines to the reconstructed image when the decimation(t) ratio is less than 1.

3. The system of claim 1 wherein the first scan line and second scan line each include a plurality of pixel scan points from a linear scanner array.

4. The system of claim 1 wherein the fingerprint scanner is a dual line scanner.

5. The system of claim 4 wherein the dual line scanner includes a primary linear scanner segment and a secondary linear scanner segment.

6. The system of claim 1 and further comprising a sensor in communication with the fingerprint scanner and the image reconstruction module.

7. The system of claim 6 wherein the sensor includes a culling module to eliminate redundant scan lines.

8. A method of scanning a fingerprint of a finger moving in a scanning direction and reconstructing a fingerprint image, the method comprising:

scanning a first scan line and a second scan line separated by a line separation distance in the scanning direction;

accumulating scan lines including at least the first scan line and the second scan line over a time period t;

determining a value for decimation(t) necessary to produce a selected y axis resolution in the scanning direction based at least in part on (line count(t) divided by line separation distance) times the selected y resolution,

where line count(t) is the number of lines accumulated as a function of the time period t, and

decimation(t) is a ratio indicative of whether the line count(t) is greater than or less than the number of lines accumulated as a function of the time period t that will result in the selected reconstructed image y resolution in the scanning direction.

9. The method of claim 8 and further comprising removing scan lines from a reconstructed image when the decimation ratio is greater than 1 and adding interpolated scan lines to the reconstructed image when the decimation ratio is less than 1.

10. The method of claim 8 and further comprising obtaining the first scan line and second scan line with a plurality of pixel scan points from a respective first linear scanner array and second linear scanner array.

11. A non-transitory computer-readable storage medium for tangibly storing thereon computer readable instructions for a method of creating an image of a finger moving in a scanning direction, the method comprising:

receiving a first scan line and a second scan line separated by a line separation distance in the scanning direction;

accumulating scan lines including at least the first scan line and the second scan line over a time period t;

determining a value for decimation(t) necessary to produce a selected y axis resolution in the scanning direction based at least in part on (line count(t)/line separation distance)* the selected y resolution,

where line count(t) is the number of lines accumulated as a function of the time period t, and

decimation(t) is a ratio indicative of whether the line count(t) is greater than or less than the number of lines accumulated as a function of the time period t that will result in the selected reconstructed image y resolution in the scanning direction.

12. The method of claim 11 and further comprising removing scan lines from a reconstructed image when the decimation ratio is greater than 1 and adding interpolated scan lines to the reconstructed image when the decimation ratio is less than 1.

13. The method of claim 11 and further comprising obtaining the first scan line and second scan line with a plurality of pixel scan points from a linear scanner array.

14. A method of scanning an object of and reconstructing an image, the method comprising:

scanning a first scan line and a second scan line separated by a line separation distance in the scanning direction;

accumulating scan lines including at least the first scan line and the second scan line over a time period t;

determining a reconstructed image resolution in the scanning direction based at least in part on [line separation distance divided by line count(t)] multiplied by decimation(t), where line count(t) is a number of lines accumulated as a function of the time period t, and

decimation(t) is a ratio indicative of whether the line count(t) is greater than or less than the number of lines as a function of the time period t that will result in the selected reconstructed image resolution in the scanning direction.

15. The method of claim 14 wherein the object is at least one of a fingerprint, a hand, and a retina.

16. The method of claim 14 and further comprising removing scan lines from a reconstructed image when the decimation ratio is greater than 1 and adding interpolated scan lines to the reconstructed image when the decimation ratio is less than 1.

17. The method of claim 14 and further comprising obtaining the first scan line and second scan line with a plurality of pixel scan points from a linear scanner array.