Techniques for using floodlight LEDs when imaging sensors have an insufficient level of detail for identifying hand gestures, and mixed-reality systems and methods of using these techniques

1 . A mixed-reality (MR) headset, comprising:

(i) a set of imaging sensors and (ii) a set of floodlight-emitting diodes (flood LEDs), the sets of imaging sensors and flood LEDs disposed along a front-facing portion of the MR headset; and

one or more processors configured to:

while the MR headset is being caused to present MR content:

in accordance with a determination that imaging data obtained from the set of imaging sensors has an insufficient level of detail to identify hand gestures:

cause illumination of a volume of physical space that includes a hand of a user using one or more flood LEDs of the set of flood LEDS,

wherein:

a virtual-third-eye center position is determined based on a position of the MR headset, wherein the virtual-third-eye center position corresponds to a point between eyes of the user, and

the volume of physical space is defined based on the virtual-third- eye center position.

2 . The MR headset of claim 1 , wherein the one or more flood LEDs comprise at least two flood LEDs positioned substantially equidistant from the virtual-third-eye center position.

3 . The MR headset of claim 1 , further comprising:

an LED driver configured to control operations of the one or more flood LEDS, wherein:

the LED driver comprises a set of safety interlocks to ensure compliance of the one or more flood LEDs with a set of safety standards, and

the set of safety standards comprises one or more of over-temperature protection (OTP), over-voltage protection (OVP), short-circuit protection (SCP), and/or a safety timer.

4 . The MR headset of claim 3 , wherein the LED driver is configured to prevent each respective flood LED of the one or more flood LEDs from operating at a 100% duty cycle.

5 . The MR headset of claim 1 , wherein:

a minimum amount of radiant exposure received by a target-hand interaction zone during activation of the flood LEDs is configured to be greater than a first radiance value; and

a maximum amount of radiant exposure received by the target-hand interaction zone during activation of the flood LEDs is configured to be less than a second radiance value.

6 . The MR headset of claim 1 , wherein the determination that the one or more imaging sensors of the set of imaging sensors are capturing imaging data having an insufficient level of detail to identify hand gestures is based on identifying one or more of:

a low-light environment;

challenging lighting conditions;

a cluttered background; and

a low-contrast background.

7 . The MR headset of claim 1 , further comprising:

one or more cover windows configured to surround each respective flood LED of the set of flood LEDs, wherein:

each respective flood LED is positioned such that a combined field of view corresponding to the one or more flood LEDs includes at least 80% coverage of the volume of physical space.

8 . The MR headset of claim 7 , wherein:

at least one of the one or more flood LEDs within a respective cover window of one or more cover windows is positioned at an angle with respect to a plane defined by a front surface of the front-facing portion, and

the respective cover window is configured and arranged such that a portion of a front surface of the respective cover window extends beyond the plane defined by the front surface of the front-facing portion.

9 . The MR headset of claim 7 , wherein each of the one or more cover windows is configured to have a transmission loss of less than 20%.

10 . The MR headset of claim 1 , wherein:

in accordance with determining that a first target-hand interaction zone-coverage threshold is required, a first set of the one or more flood LEDs is illuminated; and

in accordance with determining that a second target-hand interaction zone-coverage threshold is required, a second set of the one or more flood LEDs, distinct from the first set of one or more flood LEDs, is illuminated.

11 . The MR headset of claim 1 , wherein each of the one or more flood LEDs is configured to emit light having a wavelength between 800 and 900 nanometers.

12 . A non-transitory computer-readable storage medium including instructions that, when executed by one or more processors of an MR headset, cause the MR headset to perform operations comprising:

at the MR headset that includes (i) a set of imaging sensors, (ii) a set of flood LEDs, (iii) a display, (iv) memory, and (v) one or more processors, wherein the sets of imaging sensors and flood LEDs are disposed along a front-facing portion of the MR headset:

while the display is presenting MR content:

in accordance with a determination that one or more imaging sensors of the set of imaging sensors are capturing imaging data, illuminating, using one or more flood LEDs of the set of flood LEDs, a target-hand interaction zone,

wherein:

a virtual-third-eye center position is determined based on a position of the MR headset, wherein the virtual-third-eye center position corresponds to a point between eyes of a user, and

a volume of physical space is defined based on the virtual-third- eye center position.

13 . The non-transitory computer-readable storage medium of claim 12 , wherein the one or more flood LEDs comprise at least two flood LEDs positioned substantially equidistant from the virtual-third-eye center position.

14 . The non-transitory computer-readable storage medium of claim 12 , wherein:

the MR headset includes an LED driver configured to control operations of the one or more flood LEDs,

the LED driver comprises a set of safety interlocks to ensure compliance of the one or more flood LEDs with a set of safety standards, and

the set of safety standards comprises one or more of over-temperature protection (OTP), over-voltage protection (OVP), short-circuit protection (SCP), and/or a safety timer.

15 . A method, comprising:

at an MR headset that includes (i) a set of imaging sensors, (ii) a set of flood LEDs, (iii) a display, (iv) memory, and (v) one or more processors, wherein the sets of imaging sensors and flood LEDs are disposed along a front-facing portion of the MR headset:

while the display is presenting MR content:

in accordance with a determination that one or more imaging sensors of the set of imaging sensors are capturing imaging data,

illuminating, using one or more flood LEDs of the set of flood LEDs, a target-hand interaction zone,

wherein:

a virtual-third-eye center position is determined based on a position of the MR headset, wherein the virtual-third-eye center position corresponds to a point between eyes of a user, and

a volume of physical space is defined based on the virtual-third-eye center position.

16 . The method of claim 15 , wherein the one or more flood LEDs comprise at least two flood LEDs positioned substantially equidistant from the virtual-third-eye center position.

17 . The method of claim 15 , further comprising:

the MR headset includes an LED driver configured to control operations of the one or more flood LEDs,

the LED driver comprises a set of safety interlocks to ensure compliance of the one or more flood LEDs with a set of safety standards, and

the set of safety standards comprises one or more of over temperature protection (OTP), over voltage protection (OVP), short circuit protection (SCP), and/or a safety timer.