Structured Light Camera Depth Measurement Using Color Filter Separation
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Solution Overview
Problem
Existing 3D depth measurement methods using structured light cameras face challenges such as low accuracy for long distances, difficulty in recognizing dark, translucent, and glinting representations, and a limited depth measurement range due to shadow zones and noise.
Innovation Solution
A method and apparatus utilizing a structured light camera system with multiple projectors and an optical sensor, where overlapping light patterns are filtered using a color filter to enhance feature point localization and reduce shadow zones, increasing the depth measurement range and accuracy by combining position information from multiple feature points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a single structured light projector is used, then the device configuration is simple, but the depth measurement range is limited due to shadow zones
Solution Approach 1:
The patent divides the illumination task into multiple projectors, each projecting light patterns from different positions. This segmentation allows coverage of different spatial regions, reducing shadow zones and extending the measurable depth range while maintaining manageable device complexity through modular architecture
Solution Approach 2:
The patent transitions from a single projector configuration to a multi-projector array, adding spatial dimensionality to the illumination system. This dimensional expansion enables light to reach previously shadowed areas from multiple angles, effectively extending the depth measurement range
2Measurement precision
If multiple light patterns are projected to increase feature points, then the depth measurement accuracy improves, but the noise and shadowing effects increase
Solution Approach 1:
The patent introduces a color filter as an intermediary component that selectively transmits specific wavelength ranges. This filter mediates between the multiple light patterns and the sensor, allowing only desired spectral components to pass through, thereby reducing noise from unwanted light sources while preserving the feature points needed for accurate depth measurement
Solution Approach 2:
The patent applies different wavelength ranges to different spatial regions by using multiple projectors with distinct spectral characteristics. Each projector illuminates specific areas with optimized wavelength ranges, allowing the system to maintain high measurement precision in each local region while minimizing shadowing effects through complementary coverage
3Area of stationary object
If the depth measurement range is extended to cover long distances, then the comprehensive 3D data capture improves, but the measurement accuracy decreases
Solution Approach 1:
The patent segments the depth measurement task across multiple projectors positioned at different locations. Each projector handles a specific spatial zone, allowing the system to maintain appropriate measurement precision in each segment while collectively covering an extended depth range from short to long distances
Solution Approach 2:
The patent varies the wavelength parameters of light across different projectors, with each projector optimized for specific distance ranges. This parameter differentiation allows the system to maintain high measurement accuracy across the entire extended depth range by using appropriate wavelength-range combinations for each distance segment
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 improves depth measurement accuracy, reduces shadow zones, and extends the depth measurement range, increasing the density of 3D points while minimizing noise and shadowing effects, enabling more precise and comprehensive 3D data capture.
Implementation Method 1
separating a third light pattern into a filtered first pattern and a filtered second pattern by filtering the third light pattern using a color filter
Implementation Method 2
the third light pattern being generated by overlap between the first light pattern and the second light pattern which have been reflected from an object
Data Source
AI summary
A three-dimensional depth measuring method using a structured light camera comprising a first projector, a second projector, and an optical sensor, according to the present disclosure, comprises: a step in which a first light pattern is projected by the first projector; a step in which a second light pattern is projected by the second projector; a step of filtering, by a color filter, a third light pattern in which the first light pattern and the second light pattern reflected from an object overlap, so as to separate the third light pattern into a first filtered pattern and a second filtered pattern; a step of localizing the first filtered pattern and classifying first feature points of the first filtered pattern; a step of localizing the second filtered pattern and classifying second feature points of the second filtered pattern; and a step of obtaining position information of the object on the basis of the first feature points and the second feature points.