3D Camera Nonlinear Distance Error Correction via Pulse Phase Shift
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Solution Overview
Problem
Existing 3-dimensional distance measuring cameras, such as TOF cameras, face space constraints and high equipment costs due to the need for extensive physical movement to correct nonlinear distance errors, which also prolongs the error correction time.
Innovation Solution
A method using a pulse phase shift to adjust and correct distance nonlinearity by adjusting the phase of the output light pulse, calculating and storing distance-error correction values, and determining measurement completion without physically moving the camera, allowing for error correction at a fixed position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a stage is used to move the camera to multiple measuring points for error correction, then distance measurement accuracy is improved, but space requirements increase and equipment costs increase
Solution Approach 1:
The patent replaces the mechanical stage system with an electrical phase control system. Instead of physically moving the camera through mechanical means, the invention adjusts the phase of the modulated light signal electronically to simulate measurements at different distances, thereby eliminating the need for a mechanical stage and reducing space requirements while maintaining measurement accuracy
Solution Approach 2:
The invention changes the phase parameter of the modulated light signal to achieve equivalent measurement effects without physical movement. By varying the phase shift amount, the system simulates measurements at different object distances, allowing accurate error correction to be performed in a fixed position rather than requiring physical displacement of the camera
2Measurement precision
If a stage is used to move the camera to multiple measuring points for error correction, then distance measurement accuracy is improved, but equipment costs increase
Solution Approach 1:
The patent replaces the mechanical stage system with an electrical phase control system. Instead of physically moving the camera through mechanical means, the invention adjusts the phase of the modulated light signal electronically to simulate measurements at different distances, thereby eliminating the need for a mechanical stage and reducing space requirements while maintaining measurement accuracy
Solution Approach 2:
The invention uses a simple phase shifter component that is much cheaper than a mechanical stage system. The phase shifter can be implemented using basic electronic circuits or software control, providing the same functional capability at a fraction of the cost and complexity of mechanical positioning equipment
3Measurement precision
If the camera is moved to multiple measuring points by an operator for error measurement, then distance measurement accuracy is improved, but correction time increases
Solution Approach 1:
The invention uses periodic phase modulation of the light signal to perform multiple virtual measurements in rapid succession. By cycling through different phase shift values, the system collects error data for multiple simulated distances without physical movement, dramatically reducing the time required compared to manual operator movement
Solution Approach 2:
The system pre-calculates and stores error correction values for various distances based on phase shift measurements. Once the correction lookup table is created, actual distance measurements can be quickly corrected without requiring real-time physical movement or complex calculations, significantly reducing correction time
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 overcomes space constraints, reduces equipment costs, and significantly shortens the error correction time by enabling phase shifting within a fixed space, achieving equivalent correction results without the need for a moving stage.
Implementation Method 1
A 3-dimensional distance measuring camera, such as a time of flight (TOF) camera or the like, emits light to a subject, calculates the reflected and returned light through an equation using a sinusoidal phase, and converts a calculation result into distance information
Implementation Method 2
a phase adjusting step of adjusting a phase of an output light pulse output from a light-emitting unit by a control unit
Data Source
AI summary
This application relates to a method of correcting a nonlinear distance error of a 3-dimensional distance measuring camera using a pulse phase shift. In one aspect, the method includes adjusting a phase of an output light pulse output from a light-emitting unit, outputting the phase-adjusted output light pulse to a subject, and receiving a reflected-light pulse reflected from the subject. The method may also include mapping the adjusted phase of the output light pulse to an estimated actual distance so as to correspond thereto and calculating a measured distance using a time difference between a time point at which the output light pulse is output and a time point at which the reflected-light pulse is received. The method may further include calculating and storing a distance-error correction value for correcting a difference between the estimated actual distance and the measured distance.