Depth Image Generation Using Optical Shutter Voltage Oscillation

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Solution Overview

Problem

Existing 3D image generation techniques, such as stereo vision and time-of-flight methods, face accuracy issues with increasing object distances and are surface-dependent, making it difficult to obtain precise depth information.

Innovation Solution

A depth image generating apparatus that efficiently controls the optical shutter and light source using a driver to oscillate the driving voltage around a bias voltage, adjusts based on temperature and depth information, and employs a lookup table for optimal control variables to correct depth information, ensuring accurate depth measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If temperature compensation is implemented by oscillating driving voltage around bias voltage, then depth measurement accuracy is improved, but device complexity increases

Engineering Contradiction:
Improvedepth measurement accuracyVSAvoidcontrol circuit complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies dynamics by oscillating the driving voltage around a bias voltage rather than using a fixed voltage. The driving voltage varies dynamically based on temperature compensation values, allowing the optical shutter's transmissivity to be maintained at optimal levels despite temperature changes. This dynamic voltage adjustment compensates for temperature-induced drift in the optical shutter's characteristics, thereby improving depth measurement accuracy without requiring hardware modifications.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the electrical parameter (driving voltage) to compensate for temperature effects. By calculating temperature compensation values and adjusting the driving voltage accordingly, the system maintains optimal operation of the optical shutter across varying temperatures. This parameter change approach allows a single component (the optical shutter) to operate effectively under different thermal conditions, improving measurement accuracy while avoiding complex thermal management systems.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If optical shutter transmissivity is precisely controlled through voltage oscillation, then depth information precision is improved, but power consumption increases

Engineering Contradiction:
Improvedepth information precisionVSAvoidpower consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent employs periodic action by oscillating the driving voltage around a bias voltage at a specific frequency. This periodic voltage variation causes the optical shutter's transmissivity to modulate periodically, which is essential for the time-of-flight depth measurement technique. The periodic modulation allows the system to encode depth information in the phase of the modulated light, enabling precise depth measurement while using a relatively simple voltage control scheme that avoids continuous high-power operation.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent implements feedback by measuring the actual transmissivity of the optical shutter at different temperatures and using this information to calculate temperature compensation values. These compensation values are then fed back to adjust the driving voltage, creating a closed-loop control system. This feedback mechanism ensures that the optical shutter operates at optimal transmissivity levels despite temperature variations, improving depth measurement precision while avoiding excessive power consumption by making adjustments only when necessary.

Inventive Principle:
Principle #23Feedback

3Reliability

If temperature compensation is applied across multiple operating conditions, then reliability of depth measurement is improved, but control system complexity increases

Engineering Contradiction:
Improvedepth measurement reliabilityVSAvoidcontrol system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-measuring and storing the transmissivity characteristics of the optical shutter at multiple different temperatures before actual depth measurement operations. These pre-acquired characteristics are used to calculate temperature compensation values that are stored in memory. During operation, the system simply retrieves the appropriate compensation value based on the current temperature, rather than performing complex real-time calculations. This preliminary preparation improves measurement reliability across varying temperatures while keeping the control system relatively simple.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent addresses temperature variations by introducing a temperature dimension to the control system. Instead of trying to maintain fixed voltage conditions, the system accepts temperature as a variable parameter and adjusts the driving voltage accordingly. By measuring temperature and selecting compensation values from a temperature-dependent lookup table, the system transforms a potential source of error (temperature variation) into a controllable parameter, thereby improving reliability without requiring complex real-time thermal management hardware.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 enhances the accuracy and reliability of depth image generation by effectively modulating the optical shutter and light source, improving depth information precision across varying distances and temperatures, and reducing power consumption.

Implementation Method 1

an optical shutter 130 that is arranged on a traveling path of the reflected light and modulates a waveform of the reflected light by changing the transmissivity of the reflected light

Methodology Applied
Scientific EffectElectro-optic effect: Electro-Optic Effects

Implementation Method 2

a light source 120 that emits light to an object 10

Methodology Applied
Scientific EffectLight emission: Light

Implementation Method 3

a reflected light that is reflected by the object 10 and passes through the optical shutter 130, the reflected light including depth information regarding the object 10

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP3163317B1Method and apparatus for generating depth image
Publication Date: 2021.11.17 SAMSUNG ELECTRONICS CO LTD
  • EP3163317B1 patent drawingFigure 1
  • EP3163317B1 patent drawingFigure 2(a)~2(b)
  • EP3163317B1 patent drawingFigure 3

AI summary

A depth image generating apparatus includes a light source (120) configured to emit light; an optical shutter (130) provided on a path of the light reflected by an object and configured to modulate a waveform of the reflected light by changing a transmissivity of the optical shutter with respect to the reflected light; a driver (140) configured to apply a driving voltage to the light source and a driving voltage to the optical shutter; a temperature measurer (150) configured to measure a temperature of the optical shutter; a controller (110) configured to control driving voltages; and a depth information obtainer (160) configured to generate an image corresponding to the reflected light that passes through the optical shutter, extract a phase difference between a phase of the light emitted by the light source to the object and a phase of the reflected light, and obtain depth information regarding the object based on the phase difference.