Hybrid ToF-Imager Module for Blooming-Resistant Depth Sensing

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Solution Overview

Problem

Imaging sensors provide high-quality, high-resolution 2D images but lack depth information, while Time-of-Flight (ToF) sensors offer low-resolution depth information and are prone to stray light blooming, especially with highly reflective or absorbing materials.

Innovation Solution

A hybrid imaging system combining ToF sensors and imaging sensors, with spatially registered optical paths, uses continuous or pulsed illumination and a controller for sensor fusion, including deep neural networks to enhance depth information accuracy and resolution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If ToF sensors are used to provide depth information, then depth measurement capability is improved, but resolution and accuracy deteriorate due to stray light blooming

Engineering Contradiction:
Improvedepth measurement capabilityVSAvoiddepth information resolution
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

The patent combines ToF sensors and imaging sensors into a hybrid system where the ToF sensor captures depth information and the imaging sensor captures high-resolution 2D images. The controller integrates data from both sensors, using the imaging sensor's high-resolution data to compensate for the ToF sensor's low resolution and blooming effects, thereby achieving both depth measurement capability and high resolution.

Inventive Principle:
Principle #5Merging (Combining)

2Measurement precision

If ToF sensors image highly reflective or absorbing materials, then depth information is obtained, but accuracy deteriorates due to blooming effects

Engineering Contradiction:
Improvedepth information accuracyVSAvoidblooming effects from reflective or absorbing materials
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The imaging sensor acts as an intermediary that captures the optical scene including reflections and absorptions. The controller uses this intermediary data to identify and correct blooming artifacts in the ToF depth information, particularly for highly reflective or absorbing materials, thereby maintaining measurement accuracy under challenging optical conditions.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Manufacturing precision

If imaging sensors are used, then high-resolution 2D images are obtained, but depth information is lost

Engineering Contradiction:
Improveimage resolutionVSAvoiddepth information
Core Design Contradiction:
Manufacturing precisionVSLoss of information

Solution Approach 1:

The hybrid imaging system achieves multi-functionality where the system can simultaneously provide high-resolution 2D imaging through the imaging sensor and depth information through the ToF sensor. The controller integrates both data streams, allowing the system to deliver both high-resolution images and accurate depth information, effectively making the system universal for both imaging and ranging applications.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

The hybrid system provides more accurate, higher-resolution depth information by integrating ToF and imaging sensors, reducing blooming effects and enhancing depth map clarity.

Implementation Method 1

Time-of-Flight (ToF) sensors typically provide low-resolution depth information about a scene

Methodology Applied
Scientific EffectTime of flight: Time of Flight

Implementation Method 2

Imaging sensors typically provide high quality, high-resolution, two-dimensional images of a scene

Methodology Applied
Scientific EffectLight detection: Photoelectric Effect

Data Source

PatentEP3818392B1Hybrid time-of-flight and imager module
Publication Date: 2025.12.31 WAYMO LLC
  • EP3818392B1 patent drawingFigure 1
  • EP3818392B1 patent drawingFigure 2
  • EP3818392B1 patent drawingFigure 3A

AI summary

The present disclosure relates to systems and methods that provide both an image of a scene and depth information for the scene. An example system includes at least one time-of- flight (ToF) sensor and an imaging sensor. The ToF sensor and the imaging sensor are configured to receive light from a scene. The system also includes at least one light source and a controller that carries out operations. The operations include causing the at least one light source to illuminate at least a portion of the scene with illumination light according to an illumination schedule. The operations also include causing the at least one ToF sensor to provide information indicative of a depth map of the scene based on the illumination light. The operations additionally include causing the imaging sensor to provide information indicative of an image of the scene based on the illumination light.