Time-of-Flight Camera Re-Illumination for Weak Signal Regions

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Solution Overview

Problem

Time-of-flight camera systems face design challenges such as high power consumption and cost due to the integration of a light source, particularly in battery-powered devices, which affects the strength and accuracy of optical signals.

Innovation Solution

Smart illumination techniques concentrate optical power into smaller regions of interest within the camera's field of view, adjusting the size, shape, and location of illumination to enhance received signal strength without increasing power draw.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a light source is integrated into the time-of-flight camera system, then depth capturing capability is improved, but power consumption increases

Engineering Contradiction:
Improvedepth capturing capabilityVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies local quality by concentrating illumination only in specific regions of interest within the field of view rather than uniformly illuminating the entire scene. The illuminator adjusts its illumination pattern to target only those areas where depth information is needed, thereby reducing overall power consumption while maintaining depth capturing capability in critical regions.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent implements dynamics by making the illumination pattern adaptive and changeable over time. The system dynamically adjusts the illumination regions based on detected object positions and identified areas of interest, allowing the illuminator to concentrate power where needed while minimizing power consumption in other areas. This dynamic adjustment enables the system to maintain reliable depth capturing capability with reduced overall power consumption.

Inventive Principle:
Principle #15Dynamics

2Illumination intensity

If illumination is concentrated into smaller regions of interest, then received optical signal strength is improved, but measurement precision in other regions deteriorates

Engineering Contradiction:
Improvereceived optical signal strengthVSAvoiddepth measurement accuracy in non-illuminated regions
Core Design Contradiction:
Illumination intensityVSMeasurement precision

Solution Approach 1:

The patent applies periodic action by sequentially illuminating different regions of interest over time. The system identifies multiple regions requiring depth measurement, illuminates them in succession rather than simultaneously, and combines the depth data to create a complete depth map. This periodic illumination of different regions allows the system to maintain high received optical signal strength in each illuminated region while ultimately achieving comprehensive depth measurement coverage across the entire field of view.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent implements preliminary action by first identifying regions of interest before illuminating them. The system analyzes the scene to determine which areas contain objects or features requiring depth measurement, then directs illumination specifically to those pre-identified regions. This preliminary identification step ensures that illumination is concentrated where needed, improving received optical signal strength in those regions while avoiding waste of illumination power in areas that do not require depth measurement.

Inventive Principle:
Principle #10Preliminary action

3Area of stationary object

If the entire field of view is illuminated, then coverage area is improved, but power consumption increases

Engineering Contradiction:
Improveillumination coverage areaVSAvoidpower consumption
Core Design Contradiction:
Area of stationary objectVSUse of energy by stationary object

Solution Approach 1:

The patent applies local quality by providing non-uniform illumination distribution across the field of view. Instead of illuminating the entire field of view with uniform intensity, the system concentrates illumination in specific local regions where objects or features of interest are detected. This approach maintains adequate illumination coverage in critical areas while significantly reducing power consumption by leaving other areas unilluminated or with minimal illumination.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent implements segmentation by dividing the field of view into multiple regions and selectively illuminating only those segments that contain objects or features requiring depth measurement. The system partitions the scene based on object detection and identifies specific regions of interest, then directs illumination to those segmented areas rather than illuminating the entire field of view. This segmentation strategy maintains effective coverage of important regions while reducing overall power consumption.

Inventive Principle:
Principle #1Segmentation

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach improves time-of-flight system performance by maintaining or enhancing received optical signal strength while minimizing power consumption and cost.

Implementation Method 1

measures, for each of multiple pixels of an image sensor, the time between the emission of the light and the reception of its reflected image upon the sensor

Methodology Applied
Scientific EffectTime of flight: Time of Flight

Data Source

PatentEP3346289B1Time-of-flight camera system and method to improve measurement quality of weak field-of-view signal regions
Publication Date: 2026.03.11 GOOGLE LLC
  • EP3346289B1 patent drawingFigure 1a(i)
  • EP3346289B1 patent drawingFigure 1a(ii)
  • EP3346289B1 patent drawingFigure 1b(i)

AI summary

A time-of-flight camera system is described. The time-of-flight camera system includes an illuminator to illuminate a region within the time-of-flight camera system's field of view. The time-of-flight camera system includes an image sensor to receive optical signals from the illumination for determining depth profile information within the field of view using time-of-flight measurement techniques. The image sensor has circuitry to determine one or more regions within the field of view where a received optical signal from the illuminating was weak. The illuminator is also to re-illuminate the one or more regions with stronger light than the one or more regions received during the illuminating. Each of the one or more regions being smaller than the region. The image sensor is also to receive optical signals from the re-illumination for determining depth profile information within the one or more regions.