Emitter Array Rotation for Non-Uniform 3D Dot Projection
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Solution Overview
Problem
Conventional structured light systems produce dot projections with uniformity issues in the x and y directions of the field of view, limiting accurate measurement capabilities of 3D sensing devices like ToF cameras.
Innovation Solution
The emitter array is oriented at a non-zero angle relative to the rectilinear axis of the submount, combined with a diffractive optical element, to generate a dot projection that is non-uniform in both x and y directions, enhancing the heterogeneity of the dot pattern and improving measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the emitter array is aligned with the rectilinear axis of the submount, then the manufacturing and alignment process is simplified, but the dot projection uniformity and measurement precision across the field of view deteriorates
Solution Approach 1:
The emitter array is intentionally rotated by a non-zero angle (e.g., 45 degrees) relative to the rectilinear axis of the submount, breaking the conventional symmetric alignment. This asymmetric orientation causes the dot projection pattern to exhibit non-uniform distribution across the field of view, which improves measurement precision by enhancing the heterogeneity of the projected dots while maintaining acceptable manufacturing complexity
Solution Approach 2:
The orientation angle of the emitter array is changed from the conventional 0 degrees (aligned with rectilinear axis) to a non-zero angle. This parameter change in the geometric configuration of the emitter array directly affects the dot projection pattern, creating improved measurement precision through enhanced spatial distribution of projected dots
2Measurement precision
If the emitter array is oriented at a non-zero angle, then the dot projection heterogeneity and measurement accuracy improve, but the alignment complexity and manufacturing difficulty increase
Solution Approach 1:
The deliberate asymmetric rotation of the emitter array at a non-zero angle creates a dot projection pattern with enhanced heterogeneity. This asymmetric configuration improves measurement accuracy by ensuring better spatial distribution of dots across the field of view, while the fixed angular orientation simplifies the alignment process during manufacturing
Solution Approach 2:
The emitter array is pre-oriented at the specific non-zero angle during the manufacturing process, establishing the correct geometric configuration before assembly. This preliminary action ensures that the improved measurement accuracy is achieved without requiring complex real-time alignment adjustments during system integration
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 configuration allows for more accurate measurements by increasing the non-uniformity of the dot projection, enabling improved performance of 3D sensing devices.
Implementation Method 1
The DOE diffracts a given beam of light such that diffracted orders of the given beam are transmitted by the DOE at different angles
Data Source
AI summary
A structured light system includes a camera module and a dot projection module. The dot projection module includes a submount, an emitter array disposed on the submount, and a diffractive optical element (DOE) disposed over the emitter array. The emitter array includes a plurality of emitters arranged in a periodic emitter pattern and the emitter array is oriented at a non-zero angle relative to a rectilinear axis of the submount.