Fingerprint identification method and fingerprint identification device

• US 10,127,428 B2
• Filed: 12/18/2017
• Issued: 11/13/2018
• Est. Priority Date: 08/26/2014
• Status: Active Grant

• Current Assignee: Gingy Technology Inc.
• Original Assignee: Gingy Technology Inc.
• Inventors: Chen, Tsung-Shan, Hung, Chun-Lang
• Primary Examiner(s): Lefkowitz, Sumati
• Assistant Examiner(s): Perlman, David
• Application Number:
  US15/844,630
• Publication Number:
  US 20180107858A1
• Time in Patent Office: 330 Days
• Field of Search: None
• CPC Class Codes: G06V 10/56 relating to colour
• CPC Class Codes: G06V 40/1347 Preprocessing; Feature extraction
• CPC Class Codes: G06V 40/1365 Matching; Classification
• CPC Class Codes: G06V 40/1388 using image processing
• CPC Class Codes: H04N 1/6005 with luminance or chrominance signals, e.g. LC1C2, HSL or YUV
• CPC Class Codes: H04N 1/6008 with primary colour signals, e.g. RGB or CMY(K)

Abstract

A fingerprint identification method is provided. The fingerprint identification method includes following steps: obtaining an object image and storing a plurality of pixel data of the object image in a first color model format, where the pixel data include a plurality of first pixel values; converting the pixel data into a second color model format and obtaining a plurality of second pixel values based on the converted pixel data and a first gain value; calculating a plurality of third pixel values based on the first pixel values and the second pixel values; calculating a first standard deviation based on the third pixel values; and determining whether the first standard deviation being greater than a first preset threshold value, if the first standard deviation being greater than the first preset threshold value, recognizing the object image as a fingerprint image of a true finger.

Claims

1. A fingerprint identification method, comprising:

obtaining an object image by a fingerprint sensor, and storing a plurality of pixel data of the object image in a first color model format by a memory, wherein the pixel data comprise a plurality of first pixel values;

converting the pixel data into a second color model format by a processor, and obtaining a plurality of second pixel values based on the converted pixel data and a first gain value by the processor;

calculating a plurality of third pixel values based on the first pixel values and the second pixel values by the processor;

calculating a first standard deviation based on the third pixel values by the processor; and

determining whether the first standard deviation is greater than a first preset threshold value by the processor, if the first standard deviation is greater than the first preset threshold value, recognizing the object image as a fingerprint image of a true finger by the processor,

wherein the step of calculating the third pixel values based on the first pixel values and the second pixel values comprises;

subtracting the second pixel values from the first pixel values for obtaining the third pixel values by the processor.

2. The fingerprint identification method as claimed in claim 1, wherein the first color model format is a YUV color model format.

3. The fingerprint identification method as claimed in claim 1, wherein the first pixel values are a plurality of brightness values.

4. The fingerprint identification method as claimed in claim 1, wherein the second color model format is a RGB color model format.

5. The fingerprint identification method as claimed in claim 1, wherein the second pixel values and the third pixel values are a plurality of red pixel values, and the first standard deviation is a red pixel value standard deviation.

6. The fingerprint identification method as claimed in claim 1, wherein the step of capturing the object image, and storing the pixel data of the object image in the first color model format comprises:

capturing a complete object image by the fingerprint sensor, and sampling a portion of the complete object image to act as the object image by the processor.

7. The fingerprint identification method as claimed in claim 1, further comprising:

obtaining a plurality of fourth pixel values based on the converted pixel data and a second gain value by the processor;

calculating a plurality of fifth pixel values based on the first pixel values and the fourth pixel values by the processor; and

calculating a second standard deviation based on the fifth pixel values by the processor.

8. The fingerprint identification method as claimed in claim 7, wherein, the step of determining whether the first standard deviation is greater than the first preset threshold value by the processor, if the first standard deviation is greater than the first preset threshold value, recognizing the object image as the fingerprint image of the true finger by the processor comprises:

further determining whether the second standard deviation is less than a second preset threshold value by the processor, if the second standard deviation is less than the second preset threshold value, recognizing the object image as the fingerprint image of the true finger by the processor.

9. The fingerprint identification method as claimed in claim 7, wherein the fourth pixel values and the fifth pixel values are a plurality of green pixel values, and the second standard deviation is a green pixel value standard deviation.

10. A fingerprint identification device, comprising:

a memory;

a fingerprint sensor configured to capture an object image; and

a processor coupled to the fingerprint sensor and the memory, the processor is configured to receive the object image and store a plurality of pixel data of the object image to the memory in a first color model format,

wherein the processor converts the pixel data into a second color model format, and the processor obtains a plurality of second pixel values based on the converted pixel data and a first gain value,

wherein the processor calculates a plurality of third pixel values based on the first pixel values and the second pixel values, and the processor calculates a first standard deviation based on the third pixel values

wherein the processor determines whether the first standard deviation is greater than a first preset threshold value, if the first standard deviation is greater than the first preset threshold value, the processor recognizes the object image as a fingerprint image of a true finger,

wherein the processor respectively subtracts the second pixel values from the first pixel values for obtaining the third pixel values.

11. The fingerprint identification device as claimed in claim 10, wherein the first color model format is a YUV color model format.

12. The fingerprint identification device as claimed in claim 10, wherein the first pixel values are a plurality of brightness values.

13. The fingerprint identification device as claimed in claim 10, wherein the second color model format is a RGB color model format.

14. The fingerprint identification device as claimed in claim 10, wherein the second pixel values and the third pixel values are a plurality of red pixel values, and the first standard deviation is a red pixel value standard deviation.

15. The fingerprint identification device as claimed in claim 10, wherein the processor captures a complete object image, and the processor samples a portion of the complete object image to act as the object image.

16. The fingerprint identification device as claimed in claim 10, wherein the processor obtains a plurality of fourth pixel values based on the converted pixel data and a second gain value, and the processor calculates a plurality of fifth pixel values based on the first pixel values and the fourth pixel values,

wherein the processor calculates a second standard deviation based on the fifth pixel values.

17. The fingerprint identification device as claimed in claim 16, wherein the processor further determines whether the second standard deviation is less than a second preset threshold value, if the second standard deviation is less than the second preset threshold value, the processor recognizes the object image as the fingerprint image of the true finger.

18. The fingerprint identification device as claimed in claim 16, wherein the fourth pixel values and the fifth pixel values are a plurality of green pixel values, and the second standard deviation is a green pixel value standard deviation.