Face tracking using structured light within a head-mounted display

1. A head mounted display (HMD) comprising:

a display element configured to:

display content to a user wearing the HMD,

sequentially illuminate a portion of a face of the user inside the HMD with monochromatic light of different colors, and

wherein the content is displayed by the display element to the user for a content frame having a first time period, the monochromatic light being emitted for a second time period after the first time period has elapsed, and prior to display of additional content for a subsequent content frame; and

an optics block configured to direct light from the display element to an exit pupil of the HMD;

a camera assembly configured to:

capture images of the portion of the face illuminated by the display element with the monochromatic light of different colors; and

a controller configured to:

update a facial model that describes the portion of the face based at least in part on the captured images including the monochromatic light of different colors.

2. The HMD of claim 1 , wherein the monochromatic light is a structured light pattern.

3. The HMD of claim 1 , wherein the controller is further configured to:

determine a color representation of the portion of the face using the captured images of the portion of the face illuminated with the different monochromatic light; and

update the facial model with the determined color representation.

4. The HMD of claim 1 , wherein the display element illuminates the portion of the face using a structured light pattern, the captured images including an image of the face illuminated with the structured light pattern, the controller further configured to:

generate facial depth data using the image of the face illuminated with the structured light pattern; and

update the facial model using the facial depth data.

5. The HMD of claim 4 , wherein the controller is further configured to:

update a virtual face of an avatar of the user using the facial model of the user.

6. The HMD of claim 1 , wherein the display element comprises a first subset of pixels and a second subset of pixels, the first subset of pixels displaying the content at a first frame rate, the second subset of pixels illuminating the portion of the face at a second frame rate different than the first frame rate.

7. The HMD of claim 1 , wherein the display element is further configured to sequentially illuminate the face with monochromatic light of different colors in one or more structured light patterns, and the captured images include a set of images of the portion of the face illuminated with the different monochromatic light in the one or more structured light patterns, and the controller is further configured to:

generate facial depth data using one or more of the set of images;

determine a color representation of the portion of the face using some of the first set of images; and

generate the facial model with the facial depth data and the determined color representation.

8. A method comprising:

displaying, by a display element of a head mounted display (HMD), content to a user wearing the HMD, wherein the content is displayed by the display element to the user for a content frame having a first time period;

sequentially illuminating, by the display element, a portion of a face inside the HMD with monochromatic light of different colors, wherein the monochromatic light is emitted for a second time period after the first time period has elapsed, and prior to display of additional content for a subsequent content frame;

capturing, by a camera assembly of the HMD, images of the portion of the face illuminated by the display element with the monochromatic light of different colors;

updating a facial model that describes the portion of the face based at least in part on the captured images including the monochromatic light of different colors and the cap.

9. The method of claim 8 , wherein the monochromatic light is a structured light pattern.

10. The method of claim 8 , further comprising:

determining a color representation of the portion of the face using the captured images of the portion of the face illuminated with the monochromatic light; and

updating the facial model with the determined color representation.

11. The method of claim 8 , further comprising:

illuminating, by the display element, the portion of the face using a structured light pattern, wherein the captured images include an image of the face illuminated with the structured light pattern;

generating facial depth data using the image of the face illuminated with the structured light pattern; and

updating the facial model using the facial depth data.

12. The method of claim 11 , further comprising:

updating a virtual face of an avatar of the user using the facial model of the user.

13. The method of claim 8 , wherein the display element comprises a first subset of pixels and a second subset of pixels, the first subset of pixels displaying the content at a first frame rate, the second subset of pixels illuminating the portion of the face at a second frame rate different than the first frame rate.

14. The method of claim 8 , further comprising:

illuminating sequentially, by the display element, the face with monochromatic light of different colors in one or more structured light patterns, wherein the captured images include a set of images of the portion of the face illuminated with the monochromatic light in the one or more structured light patterns;

generating facial depth data using one or more of the set of images;

determining a color representation of the portion of the face using some of the first set of images; and

generating the facial model with the facial depth data and the determined color representation.