# US 10,484,616 B2 · Adaptive light source

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- Number: US 10,484,616 B2
- Document ID: US10484616B2
- Status: Granted
- Kind: B2
- Application number: 15/591,040
- Filed: 2017-05-09
- Published: 2017-08-31
- Granted: 2019-11-19
- Earliest claimed: 2015-11-10
- Assignees: Lumileds LLC
- Applicants: Lumileds LLC
- Inventors: Arjen Van der Sijde; Nicola Pfeffer; Quint Van Voorst-Vader; Yourii Martynov; Charles Schrama
- Web page: https://patentgrep.com/patent/US10484616B2

## CPC

- G03B 15/05: Combinations of cameras with electronic flash apparatus; Electronic flash units
- G06T 7/586: from multiple light sources, e.g. photometric stereo
- G06V 10/141: Control of illumination
- G06V 10/147: Details of sensors, e.g. sensor lenses (fingerprint or palmprint sensors G06V40/13; vascular sensors G06V40/145; eye sensors G06V40/19)
- G06V 20/10: Terrestrial scenes (scenes under surveillance with static cameras G06V20/52; scenes perceived from the exterior of a vehicle G06V20/56; scenes perceived from the interior of a vehicle G06V20/59)
- G06V 20/64: Three-dimensional [3D] objects
- G06V 40/166: {using acquisition arrangements}
- G06V 40/172: {Classification, e.g. identification}
- H04N 23/20: for generating image signals from infrared radiation only
- H04N 23/56: provided with illuminating means
- H04N 23/71: Circuitry for evaluating the brightness variation
- H04N 23/74: by influencing the scene brightness using illuminating means
- G03B 2215/0567: Solid-state light source, e.g. LED, laser
- H04N 23/69: Control of means for changing angle of the field of view, e.g. optical zoom objectives or electronic zooming
- G03B: APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR (optical parts of such apparatus G02B; photosensitive materials or processes for photographic purposes G03C; apparatus for processing exposed photographic materials G03D)
- G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06V: IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

A method includes capturing a first image of a scene, detecting a face in a section of the scene from the first image, and activating an infrared (IR) light source to selectively illuminate the section of the scene with IR light. The IR light source includes an array of IR light emitting diodes (LEDs). The method includes capturing a second image of the scene under selective IR lighting from the IR light source, detecting the face in the second image, and identifying a person based on the face in the second image.

## Claims

### Claim 1

A method, comprising:
capturing a first image of a scene;
detecting a face in a section of the scene from the first image;
creating a three dimensional profile of the face;
calculating an amount of infrared (IR) light to illuminate the section of the scene based on the first image and the three dimensional profile of the face;
activating an infrared (IR) light source to selectively illuminate the section of the scene with the amount of IR light, the IR light source comprising an array of IR light emitting diodes (LEDs);
capturing a second image of the scene under selective IR lighting from the IR light source;
detecting the face in the second image; and
identifying a person based on the face in the second image.

### Claim 2 (depends on 1)

The method of claim 1, prior to said capturing the first image of the scene, further comprising activating the IR light source to uniformly illuminate the scene with IR light by driving each of the IR LEDs in the array with a first individual current.

### Claim 3 (depends on 2)

The method of claim 2, wherein said activating the IR light source to selectively illuminate the section of the scene with IR light comprises selecting a group of IR LEDs in the array and driving each of the IR LEDs in the group with a second individual current that is greater than the first individual current.

### Claim 4 (depends on 3)

The method of claim 3, wherein a first total current comprising a sum of the first individual currents and a second total current comprising a sum of the second individual currents are equal.

### Claim 5 (depends on 1)

The method of claim 1, wherein said activating the IR light source to selectively illuminate the section of the scene with IR light comprises selecting a group of IR LEDs in the array and driving each of the IR LEDs in the group with a second individual current less than the first current, a first total current comprising a sum of the first individual currents being greater than a second total current comprising a sum of the second individual currents.

### Claim 6 (depends on 1)

The method of claim 1, wherein said capturing the first image of the scene occurs under ambient lighting.

### Claim 7 (depends on 6)

The method of claim 6, prior to said activating the IR light source to selectively illuminate the section of the scene with IR light, further comprising:
activating the IR light source to uniformly illuminate the scene with IR light;
capturing an intermediate image of the scene under uniform IR lighting from the IR light source;
detecting the face in the intermediate image; and
calculating the amount of IR light to illuminate the section of the scene based on brightness values of the face in the first image and the intermediate image.

### Claim 8 (depends on 7)

The method of claim 7, wherein said calculating the amount of IR light to illuminate the section of the scene is based on a difference between corresponding brightness value of the face from the first image and the intermediate image.

### Claim 9

A method, comprising:
capturing a first image of a scene;
detecting a face in a section of the scene from the first image;
creating a three dimensional profile of the face;
activating an infrared (IR) light source to uniformly illuminate the scene with uniform IR lighting, the IR light source comprising an array of IR light emitting diodes (LEDs);
capturing an intermediate image of the scene under the uniform IR lighting from the IR light source;
detecting the face in the intermediate image;
calculating an amount of IR light to illuminate the section of the scene based on brightness values of the face in the first and the intermediate images and the three dimensional profile of the face;
activating the IR light source to selectively illuminate the section of the scene with the amount of IR light;
capturing a second image of the scene under selective IR lighting from the IR light source;
detecting the face in the second image; and
identifying a person based on the face in the second image.

### Claim 10 (depends on 9)

The method of claim 9, wherein a first LED in the array emits IR light of a different emission spectrum than IR light emitted by a second LED in the array.

### Claim 11 (depends on 9)

The method of claim 9, wherein the array is a first array of IR LEDs, the IR light source further comprises a second array of IR LEDs, and the first array of IR LEDs and the second arrays of IR LEDs illuminate different portions of the face.

### Claim 12 (depends on 11)

The method of claim 11, wherein a first LED in the array emits IR light of a different emission spectrum than IR light emitted by a second LED in the array.

### Claim 13 (depends on 9)

The method of claim 9, wherein said identifying a person based on the face in the second image comprises comparing the face in the second image against facial images in a database and finding a match.

### Claim 14

A system, comprising:
a camera having a field of view;
an infrared (IR) light source comprising an array of IR light emitting diodes (LEDs);
nonvolatile memory storing instructions for a face detection and recognition application; and
a microprocessor encoded with instructions that, when executed by the microprocessor, cause the system to:
capture, with the camera, a first image of a scene;
detect a face in a section of the scene from the first image;
create a three dimensional profile of the face;
calculate an amount of IR light to illuminate the section of the scene based on the first image and the three dimensional profile of the face;
activate the IR light source to selectively illuminate the section of the scene with the amount of IR light;
capture, with the camera, a second image of the scene under selective IR lighting from the IR light source;
detect the face in the second image; and
identify a person based on the face in the second image.

### Claim 15 (depends on 14)

The system of claim 14, wherein the instructions that, when executed by the microprocessor, cause the system to, prior to said capturing the first image of the scene, activate the IR light source to uniformly illuminate the scene with IR light by driving each of the IR LEDs in the array with a first individual current.

### Claim 16 (depends on 15)

The system of claim 15, wherein said activating the IR light source to selectively illuminate the section of the scene with IR light comprises selecting a group of IR LEDs in the array and driving each of the IR LEDs in the group with a second individual current that is greater than the first individual current.

### Claim 17 (depends on 16)

The system of claim 16, wherein a first total current comprising a sum of the first individual currents and a second total current comprising a sum of the second individual currents are equal.

### Claim 18 (depends on 15)

The system of claim 15, wherein said activating the IR light source to selectively illuminate the section of the scene with IR light comprises selecting a group of IR LEDs in the array and driving each of the IR LEDs in the group with a second individual current less than the first individual current, a first total current comprising a sum of the first individual currents being greater than a second total current comprising a sum of the second individual currents.

### Claim 19 (depends on 14)

The system of claim 14, wherein said capturing the first image of the scene occurs under ambient lighting.

### Claim 20 (depends on 19)

The system of claim 19, wherein the instructions that, when executed by the microprocessor, cause the system to, prior to said activating the IR light source to selectively illuminate the section of the scene with IR light:
activate the IR light source to uniformly illuminate the scene with IR light capturing an intermediate image of the scene under uniform IR lighting from the IR light source;
detect the face in the intermediate image; and
calculate the amount of IR light to illuminate the section of the scene based on brightness values of the face in the first and the intermediate images.

### Claim 21 (depends on 20)

The system of claim 20, wherein said calculating the amount of IR light to illuminate the section of the scene is based on a difference between corresponding brightness value of the face from the first image and the intermediate image.

### Claim 22

A system, comprising:
a camera having a field of view;
an infrared (IR) light source comprising an array of IR light emitting diodes (LEDs);
nonvolatile memory storing instructions for a face detection and recognition application; and
a microprocessor encoded with instructions that, when executed by the microprocessor, cause the system to:
capture, with the camera, a first image of a scene;
detect a face in a section of the scene from the first image;
create a three dimensional profile of the face;
activate the IR light source to uniformly illuminate the scene with uniform IR lighting;
capture an intermediate image of the scene under the uniform IR lighting from the IR light source;
detect the face in the intermediate image;
calculate an amount of IR light to illuminate the section of the scene is based brightness values of the face in the first and the intermediate images and the three dimensional profile of the face;
activate the IR light source to selectively illuminate the section of the scene with the amount of IR light;
capture, with the camera, a second image of the scene under selective IR lighting from the IR light source;
detect the face in the second image; and
identify a person based on the face in the second image.

### Claim 23 (depends on 22)

The system of claim 22, wherein a first LED in the array emits IR light of a different emission spectrum than IR light emitted by a second LED in the array.

### Claim 24 (depends on 22)

The system of claim 22, wherein the array of IR LEDs is a first array of IR LEDs, the IR light source further comprises a second array of IR LEDs, the first and the second arrays of IR LEDs illuminate different portions of the face.

### Claim 25 (depends on 24)

The system of claim 24, wherein a first LED in the array emits IR light of a different emission spectrum than IR light emitted by a second LED in the array.

### Claim 26 (depends on 22)

The system of claim 22, wherein said identifying the person based on the face in the second image comprises comparing the face in the second image against facial images in a database and finding a match.

### Claim 27

A non-transitory, computer-readable storage medium encoded with instructions executable by a microprocessor to selectively illuminate a scene, the instructions, when executed by the microprocessor, cause performance of operations, the operations comprising:
capturing a first image of a scene;
detecting a face in a section of the scene from the first image;
creating a three dimensional profile of the face;
calculating an amount of infrared (IR) light to illuminate the section of the scene based on the first image and the three dimensional profile of the face;
activating an IR light source to selectively illuminate the section of the scene with the amount of IR light, the IR light source comprising an array of IR light emitting diodes (LEDs);
capturing a second image of the scene under selective IR lighting from the IR light source;
detecting the face in the second image; and
identifying a person based on the face in the second image.