Face tracking device

• US 20080317284A1
• Filed: 01/24/2008
• Published: 12/25/2008
• Est. Priority Date: 02/08/2007
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Inada, Junya
• Granted Patent: US 8,098,887 B2
• Time in Patent Office: Days
• US Class Current: 382/103
• CPC Class Codes: G06T 2207/10016 Video; Image sequence
• CPC Class Codes: G06T 2207/30201 Face
• CPC Class Codes: G06T 2207/30268 Vehicle interior
• CPC Class Codes: G06T 7/20 Analysis of motion motion estimation for coding, decoding, compressing or decompressing digital video signals H04N19/43, H04N19/51
• CPC Class Codes: G06T 7/251 involving models

Abstract

A face tracking device for tracking an orientation of a person'"'"'s face with using a cylindrical head model, the face tracking device comprises: an image means for continuously shooting the person'"'"'s face and for obtaining a first image data based on a shot of the person'"'"'s face; an extraction means for extracting a second image data from the first image data, the second image data corresponding to a facial area of the person'"'"'s face; a determination means for determining whether the second image is usable as an initial value required for the cylindrical head model; and a face orientation detection means for detecting the orientation of the person'"'"'s face with using the cylindrical head model and with using the initial value determined to be usable by the determination means.

Claims

1. A face tracking device for tracking an orientation of a person'"'"'s face with using a cylindrical head model, the face tracking device comprising:

an image means for continuously shooting the person'"'"'s face and for obtaining a first image data based on a shot of the person'"'"'s face;

an extraction means for extracting a second image data from the first image data, the second image data corresponding to a facial area of the person'"'"'s face;

a determination means for determining whether the second image is usable as an initial value required for the cylindrical head model; and

a face orientation detection means for detecting the orientation of the person'"'"'s face with using the cylindrical head model and with using the initial value determined to be usable by the determination means.

2. The face tracking device according to claim 1, wherein

the determination means determines whether the second image is usable as the initial value required for the cylindrical head model with using an appearance model.

3. The face tracking device according to claim 1, wherein

the person'"'"'s face is a face of a vehicle driver, and

the determination means determines whether the second image is usable as the initial value required for the cylindrical head model based on an appearance model and a driving condition signal indicative of a driving condition of a vehicle.

4. The face tracking device according to claim 3, wherein

the driving condition signal includes a signal from a steering angle sensor mounted to the vehicle.

5. The face tracking device according to claim 4, wherein

the determination means determines that the second image is usable as the initial value required for the cylindrical head model when a steering angle of the vehicle indicated by the signal from the steering angle sensor is within a predetermined steering angle judgment range, and

the predetermined steering angle judgment range is preliminarily set to include 0 degree of the steering angle.

6. The face tracking device according to claim 3, wherein

the driving condition signal includes a signal from a vehicle speed sensor mounted to the vehicle.

7. The face tracking device according to claim 6, wherein

the determination means determines that the second image is usable as the initial value required for the cylindrical head model when a vehicle speed indicated by the signal from the vehicle speed sensor is larger than a predetermined vehicle speed judgment value.

8. The face tracking device according to claim 3, wherein

the driving condition signal includes a signal from an acceleration sensor mounted to the vehicle.

9. The face tracking device according to claim 8, wherein

the determination means determines that the second image is usable as the initial value required for the cylindrical head model when an acceleration of the vehicle in the direction of vehicle movement is larger than a predetermined acceleration judgment value, the acceleration value being indicated by the signal from the acceleration sensor.

10. The face tracking device according to claim 3, wherein

the driving condition signal includes a signal from a throttle angle sensor mounted to the vehicle.

11. The face tracking device according to claim 10, wherein

the determination means determines that the second image is usable as the initial value required for the cylindrical head model when a throttle angle indicated by the signal from the throttle angle sensor is larger than a predetermined throttle angle judgment value.

12. A method for tracking an orientation of a person'"'"'s face with using a cylindrical head model, the method comprising:

obtaining a person'"'"'s face image data as a first image data;

extracting a second image data from the first image data, the second image data corresponding to a facial area of the person'"'"'s face;

determining whether the second image is usable as an initial value required for the cylindrical head model; and

detecting the orientation of the person'"'"'s face with using the cylindrical head model and with using the initial value determined to be usable.

13. A face tracking device for tracking an orientation of a person'"'"'s face with using a cylindrical head model, the face tracking device being mounted to a vehicle, the face tracking device comprising:

a facial image obtaining unit which continuously obtains a person'"'"'s face image data as a first image data;

a facial area extraction unit which extracts a second image data from the first image data, the second image data corresponding to a facial area of the person'"'"'s face;

an initial value determination unit which calculates an first fitting error value of the second image data by performing fitting process of the second image data with using an appearance model, and which determines that the second image is usable as an initial value required for the cylindrical head model when all of the following conditions are satisfied;

the first fitting error value is approximately smaller than a first predetermined error judgment value;

a steering angle of the vehicle is approximately between −

20 degree and +20 degree;

a vehicle speed is approximately faster than 30 km/h;

an acceleration of the vehicle is approximately larger than 0.03 G wherein a positive acceleration is provided by a case where the vehicle speed is being increased in the direction of vehicle movement; and

a throttle angle of the vehicle is approximately larger than 13%; and

a facial orientation tracking unit which obtains the initial value determined to be usable by the initial value determination unit, processes the initial value by fitting calculation with using the cylindrical head model, calculates a second fitting error value from the initial value with using the cylindrical head model, and determines the orientation of a person'"'"'s face when the second fitting error value is smaller than a second predetermined error judgment value.