Hybrid depth detection and movement detection

A head-mounted device (HMD) comprising:

• one or more processors;
• and
• one or more computer-readable hardware storage devices having stored thereon computer executable instructions that are executable by the one or more processors to cause the HMD to perform a method for tracking movements of the HMD in a low light environment in conjunction with determining object depth, wherein the method comprises:
• at a first selected frequency, performing at least the following:
• causing a flood infrared (IR) light illuminator to emit a flood of IR light into the low light environment;
• causing a head tracking stereo camera pair to obtain one or more images of reflected IR light resulting from the flood of IR light and reflected visible light reflecting off of one or more objects in the low light environment, wherein the head tracking stereo camera pair includes a first camera and a second camera;
• and
• using the one or more images to track the movements of the HMD;
• and
• at a second selected frequency, performing at least the following:
• causing a dot-pattern IR illuminator to emit a dot-pattern IR illumination onto at least a part of the low light environment;
• causing the head tracking stereo camera pair to capture one or more images of reflected dot-pattern IR light resulting from the dot-pattern illumination and reflected visible light;
• and
• using the one or more images of the reflected dot-pattern IR light and the reflected visible light to construct a geometric surface for at least the part of the low light environment.

One or more hardware storage device(s) having stored thereon computer executable instructions that are executable by one or more processor(s) to cause a head-mounted device (HMD) to track movements of the HMD in a low light environment in conjunction with determining object depth by causing the HMD to at least perform the following:

• at a first selected frequency, performing at least the following:
• causing a flood infrared (IR) light illuminator to emit a flood of IR light into the low light environment;
• causing a head tracking stereo camera pair to obtain one or more images of reflected IR light resulting from the flood of IR light and reflected visible light reflecting off of one or more objects in the low light environment, wherein the head tracking stereo camera pair includes a first camera and a second camera;
• and
• using the one or more images to track the movements of the HMD;
• and
• at a second selected frequency, performing at least the following:
• causing a dot-pattern IR illuminator to emit a dot-pattern IR illumination onto at least a part of the low light environment;
• causing the head tracking stereo camera pair to capture one or more images of reflected dot-pattern IR light resulting from the dot-pattern illumination and reflected visible light;
• and
• using the one or more images of the reflected dot-pattern IR light and the reflected visible light to construct a geometric surface for at least the part of the low light environment.