Spatially Coded Structured Light Generator for Sunlight Robustness
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing 3D mapping systems using structured light triangulation struggle with robustness to sunlight and require multiple frame captures to construct a 3D map, leading to complex optical systems and insufficient intensity from single laser emitters.
Innovation Solution
A spatially coded structured light generator using an array of monolithically integrated surface-emitting laser diodes, where the positions of the diodes form a non-regular unique pattern, projected via refractive or diffractive optics to create a robust structured light pattern from a single frame capture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the intensity of the structured light pattern is increased to achieve robustness to sunlight, then the system can operate in sunlight conditions, but the complexity of the optical subsystem increases due to requiring multiple lasers and beam-combining techniques
Solution Approach 1:
The patent divides the single high-power laser source into multiple lower-power laser diodes arranged in an array. Each diode emits light that is spatially coded and projected through the optical system. This segmentation allows achieving the required total intensity through parallel emission from multiple diodes rather than using a single high-power laser, thereby avoiding the complexity of beam-combining techniques while maintaining sunlight robustness.
Solution Approach 2:
The patent combines the output from multiple laser diodes in space to form a unified structured light pattern. The array of diodes is integrated monolithically and their combined light output is projected through a single refractive or diffractive optical system, merging multiple simple sources into one effective illumination system without requiring complex beam-combining optics.
2Device complexity
If a single laser emitter is used to simplify the optical system, then the device complexity is reduced, but the intensity is insufficient to be robust with respect to sunlight
Solution Approach 1:
Instead of using a single laser emitter, the patent segments the light source into an array of multiple laser diodes. Each diode contributes to the overall illumination intensity, and their combined output achieves the required brightness for sunlight robustness while keeping each individual emitter simple and manageable.
Solution Approach 2:
The patent transitions from a single-point light source to a distributed array of light sources arranged in two dimensions. This spatial distribution across multiple diodes in an array configuration enables intensity scaling by adding more emitters in the array, rather than increasing the power of a single emitter, thus achieving higher intensity without proportional increases in system complexity.
3Loss of information
If time-multiplexing strategy is used to solve the correspondence problem, then the correspondence can be determined, but multiple frame captures are required which reduces productivity
Solution Approach 1:
The patent segments the spatial information across multiple independently addressable laser diodes in the array. Each diode can be controlled to emit with a specific spatial code, allowing all correspondence information to be encoded simultaneously in a single projected pattern rather than requiring temporal sequencing of multiple patterns.
Solution Approach 2:
The patent changes the encoding parameter from temporal variation (time-multiplexing different patterns over time) to spatial variation (encoding unique information in the spatial positions and intensities of multiple diodes). This allows the correspondence problem to be solved by analyzing the spatial distribution of light in a single captured frame, eliminating the need for multiple temporal captures and improving mapping speed.
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 robustness to sunlight and constructs a 3D map from a single frame capture with a simple optical subsystem, leveraging the power scaling of integrated laser diodes for enhanced intensity and information content.
Implementation Method 1
A spatially coded structured light is generated by an array of laser diodes. The laser diodes are of the surface-emitting type, where the light is emitted in the direction perpendicular to the semiconductor wafer surface.
Implementation Method 2
The light output by the lasers is projected by a refractive or diffractive optical system into the space to be monitored to form the structured light pattern.
Implementation Method 3
The light output by the lasers is projected by a refractive or diffractive optical system into the space to be monitored to form the structured light pattern.
Data Source
AI summary
A spatially coded structured light is generated by an array of laser diodes (1) in order to perform structured light triangulation. The laser diodes (1a-c) are VCSEL, where the light is emitted in the direction perpendicular to the semiconductor wafer surface. Plural such laser diodes (1a-c) are integrated monolithically to form an array (1). The position of the individual laser diodes in the array is coded spatially to form a non-regular unique pattern. The light output by the lasers is projected by a refractive or diffractive optical system (2) into the space to be monitored to form the structured light pattern. An object (5) to be investigated may be illuminated by the VCSEL array (1) and a camera (3) captures the frames. A processing unit (4) controls the power of VCSEL (1a-c) and processes the data from the camera (3).