Time-of-Flight Sensor Depth Calculation via Linear Phase Shift

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Solution Overview

Problem

Conventional time-of-flight (ToF) sensors rely on complex trigonometric functions for depth calculation, which are computationally intensive and produce imprecise results.

Innovation Solution

A method and apparatus that determine depth information by calculating a general phase shift and incremental phase shift of reflected light relative to transmitted light using a linear relationship, eliminating the need for complex trigonometric functions and improving accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional trigonometric functions are used for depth calculation in ToF sensors, then depth information can be obtained, but computational intensity increases and precision decreases

Engineering Contradiction:

Improvedepth information precisionVSAvoidcomputational intensity

Core Design Contradiction:

Measurement precisionVSPower

Solution Approach 1:

The patent replaces complex trigonometric calculations with a simplified linear calculation method. Instead of using traditional trigonometric functions to calculate phase shift and depth, the invention uses a direct linear relationship between phase shift and depth, eliminating the need for computationally intensive trigonometric operations while maintaining measurement accuracy.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the calculation parameters from trigonometric functions to linear relationships. By expressing depth as a linear function of phase shift rather than using trigonometric relationships, the computational complexity is reduced while preserving the essential measurement capability.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If conventional trigonometric functions are used for depth calculation, then depth information can be obtained, but the system becomes more resource-intensive

Engineering Contradiction:

Improvedepth information accuracyVSAvoidsystem resource requirements

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent substitutes complex trigonometric computation systems with a simplified linear calculation system. This replacement reduces the computational resources required, simplifying the overall system architecture while maintaining the ability to accurately determine depth information from phase shift measurements.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If conventional depth calculation methods are used, then depth information is obtained, but computational time and complexity increase

Engineering Contradiction:

Improvedepth measurement accuracyVSAvoidcomputational time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces time-consuming trigonometric calculations with immediate linear calculations. The linear relationship allows for direct computation of depth from phase shift without requiring iterative or complex mathematical operations, thereby reducing computational time while preserving measurement accuracy.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 reduces computational intensity while providing more accurate depth information for ToF sensors, making them less resource-intensive and more precise.

Implementation Method 1

A time-of-flight (ToF) sensor may determine the distances of objects in its vicinity by measuring the time for light to travel from the sensor, to an object, and (after reflection) back to the sensor

Methodology Applied

Scientific EffectTime of flight: Time of Flight

Implementation Method 2

one or more light receptors to detect and/or capture the reflected light from the object

Methodology Applied

Scientific EffectLight reflection: Reflection

Data Source

PatentUS11448739B2Derivation of depth information from time-of-flight (TOF) sensor data

Publication Date: 2022.09.20 SYNAPTICS INC

AI summary

A time-of-flight sensor includes a light source to transmit periodic bursts light in a direction of one or more objects and an array of optical sensing elements to detect light reflected from the one or more objects and generate sensor data corresponding to the detected light. A distance calculator determines depth information of the one or more objects by determining a general phase shift of the reflected light relative to the transmitted light based on a first frame of the sensor data and a second frame of the sensor data, calculating an incremental phase shift of the reflected light relative to the transmitted light based on a linear relationship between the first frame and the second frame in relation to the general phase shift, and combining the general phase shift with the incremental phase shift to determine an actual phase shift of the reflected light relative to the transmitted light.