Biological information detecting device

• US 20060056700A1
• Filed: 11/08/2005
• Published: 03/16/2006
• Est. Priority Date: 05/15/2003
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Shinzaki, Takashi, Abiko, Yukihiro
• Granted Patent: US 7,965,874 B2
• Time in Patent Office: Days
• US Class Current: 382/190
• CPC Class Codes: G06T 7/66 of image moments or centre of gravity
• CPC Class Codes: G06V 10/993 Evaluation of the quality of the acquired pattern
• CPC Class Codes: G06V 40/1306 non-optical, e.g. ultrasonic or capacitive sensing
• CPC Class Codes: G06V 40/1347 Preprocessing; Feature extraction

Abstract

When an image representing biological information is input from a biological information input unit 10, such as a fingerprint sensor or the like, for obtaining an image representing biological information, such as a fingerprint or the like, statistical quantities, such as the mean value and standard deviation of the pixel values of the sampled image, are calculated. Then, using the statistical quantities, a region containing biological information is extracted, its sensitivity variations are eliminated and the effects of stains, such as a residual fingerprint is nullified, thereby generating a favorable biological image with high contrast.

Claims

1. A biological information detecting device, comprising:

a biological information input unit for sampling biological information; and

a biological information region extraction unit for calculating statistical quantities, based on a value of pixel distribution of an image sampled by the biological information input unit and extracting a region containing biological information, based on the statistical quantities.

2. The biological information detecting device according to claim 1, wherein

said biological information region extraction unit extracts a range specified using a centroid of an image sampled by said biological information input unit and a second order moment around the centroid, as a region containing biological information.

3. The biological information detecting device according to claim 1, further comprising

a sensitivity variations correction unit for correcting sensitivity variations of the sampled image, using a ratio of pixel values of the background image.

4. The biological information detecting device according to claim 1, further comprising

a partial sensitivity fluctuation correction unit for correcting partial sensitivity fluctuations by homogenizing the value of pixel levels of a background in each partial region of the sampled image.

5. The biological information detecting device according to claim 4, wherein

partial sensitivity fluctuations are corrected by homogenizing the value of pixel levels of a background after homogenizing the mean value and standard deviation of each partial region.

6. The biological information detecting device according to claim 5, wherein

if a standard deviation value of each partial region is smaller than a standard deviation value of an image whose sensitivity variations of each background image has been corrected, no standard deviation values are homogenized.

7. The biological information detecting device according to claim 1, further comprising

a sensitivity setting unit for setting a sensitivity used when sampling the biological information, wherein

a threshold value at which the respective numbers of pixels at value of pixel levels lower and higher than the specific threshold assume a predetermined ratio is set to a sensitivity obtained based on a background pixel value.

8. The biological information detecting device according to claim 1, further comprising

a value of pixel correction unit whose upper value of pixel limit based on a maximum quantization level and lower value of pixel limit based on a minimum quantization level are a background value of pixel level of an extracted biological information region and a minimum value of the value of pixel level of the biological information region, respectively.

9. The biological information detecting device according to claim 1, further comprising

an image determination unit for determining a state of the sampled image, based on a mean value and a standard deviation of the extracted biological information region.

10. The biological information detecting device according to claim 9, wherein

said image determination unit determines the state of the sampled image, based on a value obtained by normalizing the mean value and standard deviation of the extracted biological information region using a ratio between a sensitivity setting value of the sampled image and a sensitivity setting value of a background image.

11. The biological information detecting device according to claim 3, further comprising

a correction unit for eliminating noise from the sampled image, wherein

a region containing biological information is extracted according to statistical information about a value of pixel distribution of a corrected image obtained from the said sensitivity variation correction unit.

12. The biological information detecting device according to claim 1, further comprising

a sensitivity adjustment unit for setting a threshold value at which the respective numbers of pixels at value of pixel levels lower and higher than the specific threshold assume a predetermined ratio, to a sensitivity that coincides with a background brightness in a value of pixel frequency distribution of a biological information region extracted by said biological information region extraction unit.

13. The biological information detecting device according to one of claims 1 through 12, further comprising:

a biological information determination unit for not determining existence/non-existence of biological information of a sampled image in which the number of pixels in which two images consecutively sampleed beyond a predetermined threshold value have different pixel values almost equals the number of pixels in said biological information input unit, in an image group consecutively sampled using said biological information input unit; and

an unnecessary information elimination unit for eliminating unnecessary information from a sampled image, using a corrected image determined to contain no biological information.

14. A biological information detecting method, comprising:

sampling biological information; and

calculating statistical quantities, based on a value of pixel distribution of an image sampled in the biological information input step and extracting a region containing the biological information, based on the statistical quantities.

15. A program for enabling an information processing device to executing a biological information detecting method, comprising:

sampling biological information; and

calculating statistical quantities, based on a value of pixel distribution of an image sampled in the biological information input step and extracting a region containing the biological information, based on the statistical quantities.