# US 2008/0186449 A1 · Gaze tracking using multiple images

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- Number: US 2008/0186449 A1
- Document ID: US20080186449A1
- Status: Published application
- Kind: A1
- Application number: 12/025,716
- Filed: 2008-02-04
- Published: 2008-08-07
- Earliest claimed: 2007-02-04
- Assignees: Miralex Systems Incorporated
- Inventors: Sudipto Sur; Luis M. Pestana
- Web page: https://patentgrep.com/patent/US20080186449A1

## CPC

- A61B 3/113: for determining or recording eye movement
- G06V 40/19: Sensors therefor
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)
- G06V: IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING

## Abstract

Systems and methods for facilitating gaze tracking based on multiple images are disclosed. A gaze tracking system includes an optical module configured to receive illumination from a target and provide a background and tracking channel outputs, the background channel including ambient illumination and the tracking channel including ambient and controlled added illumination at a targeted range of wavelengths. The background and tracking channel outputs are provided to an imaging module configured to provide an associated set of background and tracking images to a processor module to facilitate gaze tracking. Controlled illumination of the target may be provided by an illumination element, in conjunction with the processor module, to facilitate gaze tracking.

## Claims

### Claim 1

A gaze tracking system comprising:
an optical module disposed to receive, from a target, illumination including an ambient light component and a controlled light component, and provide a background output and a tracking output, said background output consisting substantially of the ambient light component and said tracking output including the ambient light component and the controlled light component;
an imaging module disposed to receive the tracking output and the background output and provide a set of images based on the tracking output and background output; and
a processor module disposed to:
receive the set of images;
provide, based on the set of images, gaze tracking data; and
store, in a processor readable memory, the gaze tracking data.

### Claim 2 (depends on 1)

The gaze tracking system of claim 1 further comprising an illumination module disposed to provide controlled illumination to the target.

### Claim 3 (depends on 2)

The gaze tracking system of claim 2 wherein the controlled illumination is provided in response to a control signal generated at least in part in conjunction with the processor module.

### Claim 4 (depends on 3)

The gaze tracking system of claim 3 wherein the control signal is based at least in part on one or more images of said set of images.

### Claim 5 (depends on 1)

The gaze tracking system of claim 1 wherein the set of images provided by the imaging module include a set of background channel images based on the background output and a set of tracking channel images based on the tracking output.

### Claim 6 (depends on 5)

The gaze tracking system of claim 5 wherein a first image of the set of background channel images and a first image of the set of tracking channel images are captured simultaneously.

### Claim 7 (depends on 6)

The gaze tracking system of claim 6 wherein a plurality of images of the set of background channel images and a corresponding plurality of images of the set of tracking channel images are captured simultaneously.

### Claim 8 (depends on 1)

The gaze tracking system of claim 1 wherein the set of images provided by the imaging module comprises a set of composite images, each composite image of the set of composite images including a background channel image and a tracking channel image.

### Claim 9 (depends on 8)

The gaze tracking system of claim 8 wherein the tracking channel image and background channel image are captured simultaneously.

### Claim 10 (depends on 1)

The gaze tracking system of claim 1 wherein the optical module comprises a lens assembly and a filter assembly configured to generate the background output and the tracking output.

### Claim 11

The gaze tracking system of clam 10 wherein the filter assembly includes a dichroic mirror configured to provide the background output.

### Claim 12 (depends on 11)

The gaze tracking system of claim 11 further comprising a first imaging element disposed to receive the background output and generate a set of background channel images and a second imaging element disposed to receive the tracking output and generate a set of tracking channel images.

### Claim 13 (depends on 1)

The gaze tracking system of claim 1 wherein the optical module comprises a first lens assembly configured to generate the background output and a second lens assembly configured to generate the tracking output.

### Claim 14 (depends on 13)

The gaze tracking system of claim 13 further comprising a first imaging element disposed to receive the background output and generate a set of background channel images and a second imaging element disposed to receive the tracking output and generate a set of tracking channel images.

### Claim 15 (depends on 1)

The gaze tracking system of claim 1 wherein the optical module comprises:
a lens assembly;
a filter assembly disposed to generate the background output and tracking output, said filter assembly including a dichroic mirror configured to provide the background output and a second mirror configure to provide the tracking output.

### Claim 16 (depends on 15)

The gaze tracking system of claim 15 wherein the imaging module comprises a composite imaging element, said composite imaging element configured to receive the background output and tracking output and provide a set of composite images, each image of said set of composite images including a background channel image and a tracking channel image.

### Claim 17

The gaze tracking system of clam 16 wherein the background channel image and the tracking channel image are captured simultaneously.

### Claim 18 (depends on 1)

The gaze tracking system of claim 1 wherein:
the optical module comprises a first lens assembly configured to generate the background output, and a second lens assembly configured to generate the tracking output; and
the imaging module comprises a composite imaging element, said composite imaging element configured to receive the background output and tracking output, and provide a set of composite images, each image of said set of composite images including a background channel image and a tracking channel image.

### Claim 19

The gaze tracking system of clam 18 wherein the background channel image and the tracking channel image are captured simultaneously.

### Claim 20

A method of gaze tracking comprising the steps of:
receiving from a target, illumination including an ambient light component and a controlled light component;
providing, based on the received illumination, a background output and a tracking output, said background output consisting substantially of the ambient light component and said tracking output including the ambient light component and the controlled light component;
receiving, at an imaging module, the tracking output and the background output;
providing, to a processor module, a set of images based on the tracking output and background output;
generating, at the processor module, gaze tracking data; and
storing, in a processor readable memory, the gaze tracking data.

### Claim 21 (depends on 20)

The method of claim 20 further comprising providing controlled illumination to the target.

### Claim 22 (depends on 20)

The method of claim 20 wherein the controlled illumination is provided in response to a control signal generated at least in part in conjunction with the processor module.

### Claim 23 (depends on 22)

The method of claim 22 wherein the control signal is generated at least in part based on one or more images of said set of images.

### Claim 24 (depends on 20)

The method of claim 20 wherein the set of images provided by the imaging module include a set of background channel images based on the background output and a set of tracking channel images based on the tracking output.

### Claim 25 (depends on 24)

The method of claim 24 wherein a first image of the set of background channel images and a first image of the set of tracking channel images are captured simultaneously.

### Claim 26 (depends on 25)

The method of claim 25 wherein a plurality of images of the set of background channel images and a corresponding plurality of images of the set of tracking channel images are captured simultaneously.

### Claim 27 (depends on 20)

The method of claim 20 wherein the set of images provided by the imaging module comprises a set of composite images, each composite image of the set of composite images including a background channel image and a tracking channel image.

### Claim 28 (depends on 27)

The method of claim 27 wherein the tracking channel image and background channel image are captured simultaneously.

### Claim 29 (depends on 20)

The method of claim 20 wherein the background output is provided by a dichroic mirror.

### Claim 30 (depends on 20)

The method of claim 20 wherein the background output is provided by a first lens assembly and the tracking output is provided by a second lens assembly.

### Claim 31 (depends on 20)

The method of claim 20 wherein the background output is provided by a dichroic mirror and the tracking output is provided by a second mirror.

### Claim 32 (depends on 20)

The method of claim 20 wherein the set of images comprises a set of composite images, each image of said set of composite images including a background channel image and a tracking channel image.

### Claim 33 (depends on 32)

The method of claim 32 wherein the background channel image and the tracking channel image are captured simultaneously.