# US 12,007,505 B2 · Projector with spatial light modulation

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- Number: US 12,007,505 B2
- Document ID: US12007505B2
- Status: Granted
- Kind: B2
- Application number: 18/120,903
- Filed: 2023-03-13
- Published: 2023-07-06
- Granted: 2024-06-11
- Earliest claimed: 2016-09-30
- Assignees: Magic Leap, Inc.
- Applicants: Magic Leap, Inc.
- Inventors: David Cohen; Assaf Pellman; Robert D. Tekolste; Shlomo Felzenshtein; Giora Yahav
- Web page: https://patentgrep.com/patent/US12007505B2

## CPC

- G01S 7/4815: {using multiple transmitters}
- G01S 7/484: Transmitters
- G01S 7/4876: {by removing unwanted signals (G01S7/495 takes precedence)}
- G01S 17/18: wherein range gates are used
- G01S 17/894: Three-dimensional [3D] imaging with simultaneous measurement of time-of-flight at a two-dimensional [2D] array of receiver pixels, e.g. time-of-flight cameras or flash lidar
- G02B 19/0009: {having refractive surfaces only}
- G02B 27/425: {in illumination systems (mask illumination systems in photolithographic systems G03F7/70158)}
- G06T 7/521: from laser ranging, e.g. using interferometry; from the projection of structured light
- H04N 23/56: provided with illuminating means
- G02B 19/009: {for use with infrared radiation}
- G06T 2207/10028: Range image; Depth image; 3D point clouds
- G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

A time of flight based depth detection system is disclosed that includes a projector configured to sequentially emit multiple complementary illumination patterns. A sensor of the depth detection system is configured to capture the light from the illumination patterns reflecting off objects within the sensor's field of view. The data captured by the sensor can be used to filter out erroneous readings caused by light reflecting off multiple surfaces prior to returning to the sensor.

## Claims

### Claim 1

A depth detection system, comprising:
a projection system, comprising:
a projector housing having a rigid substrate,
a first light source configured to emit light through a first plurality of light shaping components and produce a first illumination pattern, the first light source being mounted to the rigid substrate, and
a second light source configured to emit light through a second plurality of light shaping components and produce a second illumination pattern complementary to the first illumination pattern, the second light source being mounted to the rigid substrate adjacent to the first light source;
an imaging sensor proximate the projection system and configured to receive light emitted by the first and second light sources after being reflected off objects within a field of view of the imaging sensor; and
a processor configured to calculate a distance between the depth detection system and the objects within the field of view of the imaging sensor by measuring an amount of time for light emitted by the first and second light sources to reflect off the objects within the field of view of the imaging sensor and return to the imaging sensor and by filtering out sensor readings associated with light reflected off surfaces outside the field of view of the imaging sensor.

### Claim 2 (depends on 1)

The depth detection system as recited in claim 1, wherein the processor filters sensor readings associated with light reflected off surfaces outside of the field of view of the imaging sensor by identifying the light emitted by the first light source that reflects off areas within the field of view of the imaging sensor corresponding to the second illumination pattern.

### Claim 3 (depends on 1)

The depth detection system as recited in claim 1, wherein the first and second illumination patterns comprise a series of parallel bars.

### Claim 4 (depends on 1)

The depth detection system as recited in claim 1, wherein the first plurality of light shaping components comprises a collimating optical element, a refractive optical element, a diffractive optical element, and a micro-lens array.

### Claim 5

A method of operating a depth detection system, the method comprising:
emitting, by a first light source of a projection system of the depth detection system, light through a first plurality of light shaping components to produce a first illumination pattern, the first light source being mounted to a rigid substrate of the projection system;
emitting, by a second light source of the projection system, light through a second plurality of light shaping components to produce a second illumination pattern complementary to the first illumination pattern, the second light source being mounted to the rigid substrate adjacent to the first light source;
receiving, by an imaging sensor proximate the projection system, light emitted by the first and second light sources after being reflected off objects within a field of view of the imaging sensor; and
calculating, by a processor of the depth detection system, a distance between the depth detection system and the objects within the field of view of the imaging sensor by measuring an amount of time for light emitted by the first and second light sources to reflect off the objects within the field of view of the imaging sensor and return to the imaging sensor and by filtering out sensor readings associated with light reflected off surfaces outside the field of view of the imaging sensor.

### Claim 6 (depends on 5)

The method of operating the depth detection system as recited in claim 5, further comprising:
filtering, by the processor of the depth detection system, sensor readings associated with light reflected off surfaces outside of the field of view of the imaging sensor by identifying the light emitted by the first light source that reflects off areas within the field of view of the imaging sensor corresponding to the second illumination pattern.

### Claim 7 (depends on 5)

The method of operating the depth detection system as recited in claim 5, wherein the first and second illumination patterns comprise a series of parallel bars.

### Claim 8 (depends on 5)

The method of operating the depth detection system as recited in claim 5, wherein the first plurality of light shaping components comprises a collimating optical element, a refractive optical element, a diffractive optical element, and a micro-lens array.