Dual-Pattern 3D Optical Dimensioning Under Thermal Misalignment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional optical 3D dimensioning systems face accuracy issues due to variations in projector, camera, and projector-camera pair positions and orientations caused by thermal changes, structural deformations, and material thermal expansion, which are difficult to calibrate and correct.
Innovation Solution
A dual-pattern optical system using a single piece optical component with a light emitting assembly that generates non-repeating full field patterns, employing a single projector with a beam splitter to produce two distinct patterns, which are encoded for improved alignment and separation, minimizing overlap and enhancing measurement robustness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single projector is used with a beam splitter to generate dual patterns, then device complexity and manufacturing cost are reduced, but pattern separation accuracy and alignment precision become more difficult to maintain under thermal variations
Solution Approach 1:
The patent combines two pattern generation functions into a single projector system using a beam splitter. The single projector projects both the first pattern (e.g., vertical lines) and the second pattern (e.g., horizontal lines) simultaneously or sequentially, reducing device complexity while maintaining measurement capability through integrated optical path splitting.
Solution Approach 2:
The patent encodes the two patterns with distinct characteristics (different orientations, frequencies, or temporal sequences) to enable differentiation by the camera. This parameter encoding allows the system to distinguish and process each pattern independently despite using a single projector, maintaining pattern separation accuracy under varying conditions.
2Ease of manufacture
If multiple materials with different thermal expansion coefficients are used in camera module, then manufacturing flexibility and cost are improved, but thermal expansion causes pattern image position shifts and dimensioning errors
Solution Approach 1:
The patent acknowledges that thermal expansion causes both projector and camera to shift by similar amounts. By using the same dual-pattern approach for both projection and capture, the system makes the dimensioning calculation invariant to these shifts. The harm of thermal expansion is converted into a benefit where systematic shifts cancel out in the relative measurement.
Solution Approach 2:
The patent uses identical materials (e.g., aluminum) for both the projector housing and camera housing to ensure they experience similar thermal expansion characteristics. This homogeneity in material selection ensures that thermal shifts affect both components uniformly, maintaining the relative geometric relationship needed for accurate dimensioning.
3Measurement precision
If calibration is used to correct position and orientation variations, then dimensioning accuracy is partially improved, but non-calibratable variations from shock, vibration, and thermal gradients remain uncorrected
Solution Approach 1:
The patent segments the measurement into two independent pattern projections that can be processed separately. By encoding features in different orientations (vertical and horizontal lines), the system can independently measure dimensional changes in different directions, making the overall measurement less sensitive to single-axis thermal or mechanical distortions that calibration cannot correct.
Solution Approach 2:
The patent transforms the measurement approach by using pattern encoding (frequency, orientation, temporal sequence) instead of relying solely on geometric calibration. This parameter-based encoding allows the system to identify and measure features even when absolute positions shift due to uncalibratable effects like shock or thermal gradients.
4Device complexity
If conventional single-pattern projection is used, then system simplicity is maintained, but pattern overlap and reduced measurement robustness occur
Solution Approach 1:
The patent uses temporal sequencing to project the first pattern and second pattern at different times or in different phases. This periodic action allows the camera to capture distinct patterns without overlap, improving measurement robustness while maintaining system simplicity through time-division multiplexing of the projection.
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
The system achieves accurate 3D dimensioning by minimizing the impact of camera focusing and distortion changes, reducing manufacturing costs, and improving pattern matching accuracy, even with variations in camera position.
Implementation Method 1
an imaging assembly configured to sense light scattered and/or reflected of the object
Implementation Method 2
an imaging assembly configured to sense light scattered and/or reflected of the object
Implementation Method 3
employing a single projector with a beam splitter to produce two distinct patterns
Data Source
Figure 1A
Figure 1B
Figure 2A~2B
AI summary
A computer-implemented method of analyzing a dual-pattern, the computer implemented method comprising: projecting a full-field dual-pattern to a full projection field, the full-field dual-pattern comprising a full-field left pattern and a full-field right pattern associated with a baseline offset; identifying at least one portion of the full-field left pattern; identifying at least one portion of the full-field right pattern matching the portion of the full-field left pattern; determining a dimensioning offset between features of the portion of the full-field left pattern and features of the portion of the full-field right pattern; and calculating the dimensioning parameters of an object based on the dimensioning offset and the baseline offset.