OPTICAL INPUT DEVICE AND INPUT DETECTION THEREOF

• US 20130194236A1
• Filed: 11/07/2012
• Published: 08/01/2013
• Est. Priority Date: 11/21/2011
• Status: Abandoned Application

• Current Assignee: PixArt Imaging Incorporated
• Original Assignee: PixArt Imaging Incorporated
• Inventors: GU, Ren-Hau, KAO, Ming-Tsan, HUANG, Sen-Huang
• Application Number:
  US13/671,230
• Publication Number:
  US 20130194236A1
• Time in Patent Office: Days
• US Class Current: 345/175
• CPC Class Codes: A61B 1/00172 with means for scanning
• CPC Class Codes: G06F 2203/0338 Fingerprint track pad, i.e. fingerprint sensor used as pointing device tracking the fingertip image
• CPC Class Codes: G06F 3/0425 using a single imaging device like a video camera for tracking the absolute position of a single or a plurality of objects with respect to an imaged reference surface, e.g. video camera imaging a display or a projection screen, a table or a wall surface, on which a computer generated image is displayed or projected tracking a projected light spot to determine a position on a display surface G06F3/0386
• CPC Class Codes: G06V 40/1324 by using geometrical optics, e.g. using prisms G06V40/1312 takes precedence
• CPC Class Codes: G06V 40/1382 Detecting the live character of the finger, i.e. distinguishing from a fake or cadaver finger

Abstract

An optical input device integrates functions of fingerprint recognition, movement detection, and physiological analysis, and has a touch surface for receiving touch input of a finger. When a finger contacts the touch surface, the optical input device captures images from the touch surface, detects movement of the finger to generate a movement signal, extracts a fingerprint feature and a vessel blood changing feature from the images, analyzes and compares the fingerprint feature for identity recognition, and performs calculation according to the vessel blood changing feature to generate a physiological signal.

Claims

1. An optical input device comprising:

a touch surface receiving touch input of a finger;

a light source configured to project light to the touch surface;

an image sensor configured to capture an image from the touch surface to generate an image signal;

a touch detection unit coupled to the image sensor, configured to detect presence of the finger according to the image, detect a position of the finger to generate a position signal, and extract a fingerprint feature and a vessel blood changing feature from the image;

a fingerprint recognition unit coupled to the touch detection unit, configured to analyze and compare the fingerprint feature to generate an identity signal;

a movement detection unit coupled to the touch detection unit, configured to generate a movement signal according to the position signal; and

a physiological analysis unit coupled to the touch detection unit, configured to generate a physiological signal according to the vessel blood changing feature.

2. The optical input device of claim 1, further comprising a light controller coupled to the light source, configured to control the light source,

3. The optical input device of claim 2, wherein the light source is controlled to project light continuously and stably when the image sensor captures the image.

4. The optical input device of claim 2, wherein the touch detection unit is coupled to the light controller and generates a control signal according to a brightness of the image for the light controller to adjust a light intensity of the light source.

5. The optical input device of claim 2, wherein the image sensor captures a plurality of frames of images, including a first frame of image captured when the light source projects light and a second frame of image captured when the light source does not project light, and the touch detection unit subtracts the second frame of image from the first frame of image for reducing ambient noise interference.

6. The optical input device of claim 2, wherein the image sensor captures a plurality of frames of images, including a first frame of image captured when the light source projects light and a plurality of second frames of images captured when the light source does not project light, and the touch detection unit subtracts an average of the second frames of images from the first frame of image for reducing ambient noise interference.

7. The optical input device of claim 1, wherein the image sensor captures a plurality of frames of images, and the touch detection unit averages the plurality of frames of images for generating the vessel blood changing feature.

8. The optical input device of claim 1, further comprising:

a communication protocol interface coupled to the fingerprint recognition unit, the movement detection unit, and the physiological analysis unit, configured to encode or sort the identity signal, the movement signal, and the physiological signal, to generate a communication signal; and

a transceiver coupled to the communication protocol interface, configured to send the communication signal outward.

9. The optical input device of claim 8, wherein the transceiver receives an incoming signal which is further decoded by the communication protocol interface and transmitted to the touch detection unit or the fingerprint recognition unit.

10. A method for input detection of an optical input device having a touch surface for receiving touch input of a finger, the method comprising:

a.) capturing an image by receiving reflected light from the touch surface;

b.) detecting presence of the finger according to the image;

c.) detecting a position of the finger to generate a position signal;

d.) extracting a fingerprint feature and a vessel blood changing feature from the image;

e.) analyzing and comparing the fingerprint feature to generate an identity signal;

f.) performing calculation according to the position signal to generate a movement signal; and

g.) performing calculation according to the vessel blood changing feature to generate a physiological signal.

11. The method of claim 10, wherein the step a comprises projecting light continuously and stably to the touch surface when capturing the image.

12. The method of claim 10, wherein the step a comprises adjusting an intensity of light projected to the touch surface according to a brightness of the image.

13. The method of claim 10, wherein the step a comprises:

capturing a first frame of image when projecting light to the touch surface;

capturing a second frame of image when light is not projected to the touch surface; and

subtracting the second frame of image from the first frame of image for reducing ambient noise interference.

14. The method of claim 10, wherein the step a comprises:

capturing a first frame of image when projecting light to the touch surface;

capturing a plurality of second frames of images when light is not projected to the touch surface;

obtaining an average of the plurality of second frames of images; and

subtracting the average from the first frame of image for reducing ambient noise interference.

15. The method of claim 10, wherein the step d comprises averaging a plurality of frames of images to generate the vessel blood changing feature.

16. The method of claim 10, further comprising:

encoding or sorting the identity signal, the movement signal, and the physiological signal to generate a communication signal; and

sending the communication signal outward.

17. A method for input detection of an optical input device having a touch surface for receiving touch input of a finger, the method comprising:

a.) capturing an image by receiving reflected light from the touch surface;

b.) detecting presence of the finger according to the image;

c.) extracting a fingerprint feature from the image to analyze and compare for identify recognition;

d.) detecting a position of the finger to generate a position signal and extracting a vessel blood changing feature from the image after a legal identity is recognized in the step c;

e.) detecting movement of the finger according to the position signal;

and

f.) performing calculation according to the vessel blood changing feature to generate a physiological signal.

18. The method of claim 17, further comprising monitoring the physiological signal when the finger stays still on the touch surface.