Time-of-Flight Object Detection Circuitry Reflectivity Analysis

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Solution Overview

Problem

Existing time-of-flight object detection systems face challenges such as distance-dependent active light reflectance signals, increased motion blur, and suboptimal exposure control, which hinder accurate object detection and recognition, particularly in applications like automotive and mobile face recognition.

Innovation Solution

A time-of-flight object detection circuitry and method that obtain reflectivity data, determine the reflectivity of a scene, and generate distance-independent time-of-flight image data to improve object region detection and recognition by combining active light reflectance, depth, and surface characteristic signals, with dynamic exposure and gain control based on reflectivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If time-of-flight measurement is performed using active light reflectance, then distance information can be obtained, but the signal becomes distance-dependent causing detection inaccuracies

Engineering Contradiction:
Improveobject detection accuracyVSAvoiddistance-independent reflectivity information
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent transforms the distance-dependent active light reflectance signal into a distance-independent reflectivity signal by applying computational corrections. The system calculates reflectivity values that are normalized across different distances, enabling accurate material identification and object detection regardless of distance variations. This parameter transformation resolves the contradiction by preserving reflectivity information while eliminating distance dependency.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If exposure time is extended to improve signal quality, then measurement precision increases, but motion blur increases reducing detection accuracy

Engineering Contradiction:
Improvesignal qualityVSAvoidmotion blur
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent implements dynamic exposure control that adapts exposure time based on scene reflectivity characteristics. By continuously monitoring reflectivity data and adjusting exposure parameters in real-time, the system optimizes the balance between signal quality and motion blur. This dynamic adjustment allows shorter exposures for highly reflective surfaces and longer exposures for darker surfaces, resolving the contradiction adaptively.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system employs feedback mechanisms where reflectivity measurements from previous frames inform exposure settings for subsequent frames. This closed-loop control enables the system to anticipate lighting conditions and adjust exposure accordingly, improving signal quality while minimizing motion blur through predictive adaptation rather than reactive correction.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If gain is increased to amplify weak signals, then signal quality improves, but noise increases reducing detection reliability

Engineering Contradiction:
Improvesignal amplificationVSAvoidnoise level
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent transforms gain adjustment from a blanket amplification approach to a spatially and temporally selective process. By analyzing reflectivity patterns and temporal signal characteristics, the system applies gain only where and when needed, preserving weak signals while suppressing noise amplification. This selective parameter modification resolves the contradiction by making gain application context-dependent rather than uniform.

Inventive Principle:
Principle #35Parameter changes

4Measurement precision

If reflectivity-based object detection is implemented, then object region detection accuracy improves, but computational complexity increases

Engineering Contradiction:
Improveobject region detection accuracyVSAvoidcomputational processing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the computational process into distinct stages: reflectivity calculation, threshold comparison, and region identification. By dividing the complex detection task into modular segments that can be processed independently and in parallel, the system achieves high detection accuracy while managing computational complexity through structured decomposition of the processing pipeline.

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 enables efficient object detection and recognition by generating distance-independent reflectivity signals for improved feature extraction and object classification, enhancing the accuracy of object detection and recognition in various applications.

Implementation Method 1

in a case of iToF (indirect time-of-flight), a phase shift is measured, which is indicative of the run-time

Methodology Applied
Scientific EffectPhase shift:

Implementation Method 2

a run-time of emitted light, which is reflected at a scene, is measured for determining a distance to the scene

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentUS20230033352A1Time-of-flight object detection circuitry and time-of-flight object detection method
Publication Date: 2023.02.02 SONY SEMICON SOLUTIONS CORP
  • US20230033352A1 patent drawing
  • US20230033352A1 patent drawing
  • US20230033352A1 patent drawing

AI summary

The present disclosure generally pertains to a time-of-flight object detection circuitry configured to: obtain reflectivity data being indicative of reflectivity of a scene; determine the reflectivity of the scene; determine a region of an object in the scene based on the determined reflectivity; and generate time-of-flight image data based on the determined region of the object for detecting the object.