Light-based radar system for augmented reality
A system and method for measuring depth using an optical radar system are described. The system includes an optical radar, a camera, a display, and a processor. The optical radar emits a signal towards an object. The processor identifies an object depicted in an image captured with the camera. The processor generates the signal with a non-repeating pattern of amplitude and frequency, and computes a depth of the object based on a difference in phase angle between the signal emitted from the optical radar and a return signal received at the optical radar. The depth includes a distance between the optical radar and the object. The processor generates AR content based on the identified object and adjusts a characteristic of the AR content in the display based on the computed depth of the object.
1. A device comprising:
a camera configured to generate an image depicting an object;
a display;
a light modulator configured to modulate a light signal with a non-repeating pattern of random amplitude and random frequency;
an emitter coupled to the light modulator, the emitter being configured to generate the modulated light signal with the non-repeating pattern of amplitude and frequency, and to emit the modulated light signal;
a receiver configured to receive the return signal including the modulated light signal reflected back from the object;
a mirror configured to reflect the modulated light signal from the emitter towards the object;
a mirror controller coupled to the minor, the mirror controller being configured to adjust a direction of the mirror and to sweep the modulated light signal into a planar region defined by a first angle for horizontal sweeps and by a second angle for vertical sweeps; and
a hardware processor comprising an augmented reality (AR) application, the AR application being configured to:
identify the object depicted in the image;
compute a depth of the object based on a difference in phase angle between the emitted modulated light signal and the received return signal, the depth including a distance between the device and the object;
identify a first depth resolution of the planar region;
identify an area of interest in the planar region;
adjust the first angle and the second angle to sweep the modulated light signal in the area of interest at a second depth resolution that is higher than the first depth resolution, the second depth resolution having a higher density of sampling points than that of the first depth resolution; and
generate AR content based on the identified object and to adjust a characteristic of the AR content in the display based on the computed depth of the object.
2. The device of claim 1 , wherein the depth sensing module comprises:
a unique signal pattern generator coupled to the light modulator, the unique signal pattern generator being configured to select the random amplitude and random frequency of the modulated light signal; and
a depth computation module configured to determine a shift in the phase angle between the modulated light signal generated from the emitter and the modulated light signal received at the receiver.
3. The device of claim 2 , wherein the depth computation module is configured to identify a first pattern in a portion of the modulated light signal generated from the emitter, to identify a second pattern in a portion of the modulated light signal received at the receiver, to match the first pattern with the second pattern, and to determine the shift in the phase angle between the first pattern and the second pattern.
4. The device of claim 3 , wherein the depth computation module is configured to compute the distance between the device and the object based on the shift in the phase angle between the first pattern and the second pattern.
5. The device of claim 1 , wherein the display comprises a transparent display of a visor of a helmet,
wherein the rendering module adjusts a combination of at least a size of the AR content displayed in the transparent display and a depth of field of the AR content based on the measured depth of the object.
6. A method comprising:
identifying an object depicted in an image captured with a camera of a device;
modulating a light signal with a non-repeating pattern of random amplitude and random frequency;
reflecting the modulated light signal from the emitter on a mirror towards the object;
adjusting a direction of the mirror to sweep the modulated light signal into a planar region defined by a first angle for horizontal sweeps and by a second angle for vertical sweeps;
computing, using a processor of the device, a depth of the object based on a difference in phase angle between the emitted modulated light signal and the received return signal, the depth including a distance between the device and the object;
identifying a first depth resolution of the planar region;
identifying an area of interest in the planar region;
adjusting the first angle and the second angle to sweep the modulated light signal in the area of interest at a second depth resolution that is higher than the first depth resolution, the second depth resolution having a higher density of sampling points than that of the first depth resolution;
generating and displaying AR content based on the identified object in a display of the device; and
adjusting a characteristic of the AR content in the display based on the computed depth of the object.
7. The method of claim 6 , further comprising:
selecting the random amplitude and random frequency of the modulated light signal; and
determining a shift in the phase angle between the modulated light signal generated from the emitter and the modulated light signal received at the receiver.
8. The method of claim 7 , further comprising:
identifying a first pattern in a portion of the modulated light signal generated from the emitter;
identifying a second pattern in a portion of the modulated light signal received at the receiver;
matching the first pattern with the second pattern; and
determining the shift in the phase angle between the first pattern and the second pattern.
9. The method of claim 7 , further comprising:
computing the distance between the device and the object based on the shift in the phase angle between the first pattern and the second pattern.
10. A non-transitory machine-readable medium comprising instructions that, when executed by one or more processors of a machine, cause the machine to perform operations comprising:
modulating a light signal with a non-repeating pattern of random amplitude and random frequency;
reflecting the modulated light signal from the emitter on a mirror towards the object;
adjusting a direction of the mirror to sweep the modulated light signal into a planar region defined by a first angle for horizontal sweeps and by a second angle for vertical sweeps;
computing a depth of the object based on a difference in phase angle between the emitted modulated light signal and the received return signal, the depth including a distance between the device and the object;
identifying a first depth resolution of the planar region;
identifying an area of interest in the planar region;
adjusting the first angle and the second angle to sweep the modulated light signal in the area of interest at a second depth resolution that is higher than the first depth resolution, the second depth resolution having a higher density of sampling points than that of the first depth resolution;
generating and displaying AR content based on the identified object in a display of the device; and
adjusting a characteristic of the AR content in the display based on the computed depth of the object.