TOF Depth Distortion Correction via Multi-Reflection Separation

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Solution Overview

Problem

Time-of-flight (TOF) image capturing apparatuses face distortion in depth images due to multiple reflection of light, which affects the accuracy of depth information obtained, especially in wide field of view scenarios where direct and multi-reflective light beams mix, causing errors in depth measurement.

Innovation Solution

The apparatus emits light beams with different phases, captures original images, determines original depth values based on phase delays, calculates imaginary intensities of multi-reflective light beams in high-intensity regions, and corrects these values to generate corrected depth images, reducing distortion caused by multiple reflections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If light beams are emitted to capture depth information in wide field of view scenarios, then depth coverage is improved, but depth measurement accuracy deteriorates due to multiple reflection of light

Engineering Contradiction:

Improvefield of viewVSAvoiddepth measurement accuracy

Core Design Contradiction:

Area of stationary objectVSMeasurement precision

Solution Approach 1:

The patent segments the captured light signals into direct light components and multi-reflective light components based on their different propagation paths and characteristics. By separating these components and processing them differently, the system maintains wide field of view coverage while improving depth measurement accuracy by eliminating the distorting effect of multi-reflective light.

Inventive Principle:

Principle #1Segmentation

2Use of energy by moving object

If multiple reflection light beams are included in depth measurement, then light utilization is improved, but depth value accuracy deteriorates due to distortion

Engineering Contradiction:

Improvelight utilizationVSAvoiddepth value accuracy

Core Design Contradiction:

Use of energy by moving objectVSMeasurement precision

Solution Approach 1:

The patent converts the harmful effect of multi-reflective light (which causes depth distortion) into a beneficial separation process. By identifying and isolating multi-reflective light components from direct light components, the system eliminates their harmful distorting effect while maintaining efficient use of available light signals for depth measurement.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Illumination intensity

If direct and multi-reflective light beams are mixed in capture, then signal intensity is improved, but depth image accuracy deteriorates due to distortion

Engineering Contradiction:

Improvesignal intensityVSAvoiddepth image accuracy

Core Design Contradiction:

Illumination intensityVSMeasurement precision

Solution Approach 1:

The patent extracts and removes the multi-reflective light components from the mixed light signals captured in wide field of view scenarios. By taking out the distorting multi-reflective light portion separately from the useful direct light portion, the system maintains adequate signal intensity while improving depth image accuracy through selective extraction and removal of harmful components.

Inventive Principle:

Principle #2Taking out (Extraction)

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 method effectively reduces distortion in depth images by accurately accounting for multi-reflective light effects, improving the accuracy of depth measurements and reducing errors in TOF imaging systems.

Implementation Method 1

emitting light beams having different phases from each other to a subject

Methodology Applied

Scientific EffectLight: Light

Implementation Method 2

determining original depth values of original depth images obtained from the plurality of original images, based on phase delays of the reflected light beams

Methodology Applied

Scientific EffectPhase delay:

Implementation Method 3

an optical shutter; an image sensor configured to sense the light beams reflected from the subject and incident onto the optical shutter

Methodology Applied

Scientific Effect:

Data Source

PatentUS10430956B2Time-of-flight (TOF) capturing apparatus and image processing method of reducing distortion of depth caused by multiple reflection

Publication Date: 2019.10.01 SAMSUNG ELECTRONICS CO LTD

AI summary

An image processing method for reducing distortion of a depth image may include: obtaining a plurality of original images based on light beams which are emitted to and reflected from a subject; determining original depth values of original depth images obtained from the plurality of original images, based on phase delays of the light beams, the reflected light beams comprising multi-reflective light beams that distort the original depth values; determining imaginary intensities of the multi-reflective light beams with respective to each phase of the multi-reflective light beams, based on regions having intensities greater than a predetermined intensity in the original depth images; correcting the original depth values of the original depth images, based on the imaginary intensities of the multi-reflective light beams; and generating corrected depth images based on the corrected original depth values.