Method and apparatus for tracking listener's head position for virtual stereo acoustics

Abstract

A method and apparatus for tracking a listener's head position for virtual stereo acoustics. The method of tracking the head position of a listener includes: obtaining face images of the listener using two image pickup units; tracking the skin color of an image, thereby obtaining the two-dimensional (2D) coordinate value of the listener's position; and obtaining the distance between the image pickup units and the listener using triangulation.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The above and/or other aspects and advantages of the present invention will become apparent and more readily appreciated from the following detailed description, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a block diagram illustrating a structure of an apparatus for tracking the position of the head of a listener for virtual stereo acoustics according to an embodiment of the present invention;

FIG. 2 is a block diagram illustrating a more detailed structure of a 2D coordinate value generation unit of FIG. 1;

FIG. 3 is a block diagram illustrating a more detailed structure of a distance calculation unit of FIG. 1;

FIG. 4 is a flowchart illustrating a method of tracking the position of the head of a listener according to an embodiment of the present invention;

FIG. 5 is a more detailed flowchart illustrating an operation for calculating a 2D coordinate value of FIG. 4 using a color tracking method;

FIG. 6 is a more detailed flowchart illustrating an operation for calculating the distance between an image pickup unit and a listener of FIG. 4;

FIG. 7 illustrates a skin layer L_1N and a background layer L_2N obtained by using a multivariate Gaussian classifier according to an embodiment of the present invention;

FIG. 8 illustrates segmentation of the skin layer L_1N of FIG. 7;

FIG. 9 illustrates application of a method of tracking the position of the head of a listener in a region of interest (ROI) according to an embodiment of the present invention; and

FIG. 10 illustrates a geometric structure of a stereo vision system according to an embodiment of the present invention.

Claims

1. A method of tracking a position of a head of a listener, the method comprising: obtaining two images of the listener respectively using two image pickup units;tracking a skin color of one of the images, thereby obtaining a 2-dimensional (2D) coordinate value of the position; andobtaining a distance between the image pickup units and the listener using stereo area correlation.

2. The method of claim 1, wherein the obtaining of the 2D coordinate value of the listener's position comprises: detecting a skin region using a Gaussian skin classifier;generating a binary image of the skin region by detecting an edge of the skin region of the one of the images;expanding the skin binary image using a line-structuring element;detecting the skin region corresponding to the head by performing morphological image processing; andobtaining a center of the head.

3. The method of claim 2, wherein the Gaussian skin classifier is only applied to a region of interest (ROI).

4. The method of claim 2, wherein the method is performed in units of frames.

5. The method of claim 1, wherein the obtaining the distance between the image pickup units and the listener comprises: obtaining the two images using the two image pickup units from different angles of vision, respectively;obtaining a distance (xr−xl) between the two images; andobtaining the distance between the image pickup units and the listener using the following equation: Zo=fd/(xr−xl), andwherein Zo is the distance and assuming that coordinates of a 3-dimensional position of the listener are P(Xo, Yo, Zo), a focal distance of each of the image pickup units is f, and a distance between the image pickup units is d.

6. An apparatus for tracking a position of a head of a listener, the apparatus comprising: a first image pickup unit capturing a first image of the face of the listener;a second image pickup unit capturing a second image of the face of the listener from a second angle of vision different from the first;a 2-dimensional (2D) coordinate value generation unit generating a 2D coordinate value of the position by tracking a skin color of the image; anda distance calculation unit calculating a distance between the image pickup units and the listener using stereo area correlation.

7. The apparatus of claim 6, wherein the 2D coordinate value generation unit comprises: a skin region detection unit detecting a skin region using a Gaussian skin classifier;a binary image generation unit generating a binary image of the skin region by detecting an edge of the skin region of the first image;a binary image expansion unit expanding the skin binary image using a line-structuring element;a head detection unit detecting the skin region corresponding to the head by performing morphological image processing; anda head coordinate generation unit obtaining a center of the head.

8. The apparatus of claim 7, wherein the Gaussian skin classifier is only applied to a region of interest (ROI).

9. The apparatus of claim 7, wherein the tracking of the position of the head is performed in units of frames.

10. The apparatus of claim 6, wherein the distance calculation unit comprises: an image acquisition unit obtaining the two images of the listener using the two image pickup units from different angles of vision, respectively;an inter-image distance obtaining unit obtaining a distance (xr−xl) between the two images; anda listener's position calculation unit obtaining the distance between the image pickup units and the listener by using the following equation: Zo=fd/(xr−xl), andwherein Zo is the distance and the coordinates of the 3-dimensional position of the listener are P(Xo, Yo, Zo), the focal distance of each of the image pickup units is f, and the distance between the image pickup units is d.

11. An apparatus, comprising: two image pickup units respectively capturing two images of a face;a 2-dimensional coordinate value generation unit generating a 2D coordinate value of a position of the face by tracking a skin color region of one of the captured images; anda distance calculation unit calculating a distance from the image pickup units to the listener using stereo area correlation of the two images.

12. A method, comprising: capturing two images of a listener's face from different perspectives via two image capturing units;determining a 2D coordinate position of the face by tracking a skin color region of one of the captured images; andcalculating a distance from the image capturing units to a head of the listener via triangulation based on the two images.

13. A method of resetting a location of a sweet spot, comprising: determining a position of head of a listener by capturing two images of a listener's face from different perspectives via two image capturing units,determining a 2D coordinate position of the face by tracking a skin color region of one of the captured images, andcalculating a distance from the image capturing units to a head of the listener via triangulation based on the two images; andresetting a sweet spot to coincide with the determined position.

14. A computer readable recording medium having embodied thereon a computer program for executing the method of claim 1.

15. A computer readable recording medium having embodied thereon a computer program for executing the method of claim 12.

16. A computer readable recording medium having embodied thereon a computer program for executing the method of claim 13.