3D Machine-Vision System With Dual Camera Pairs
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Solution Overview
Problem
Current 3D machine-vision systems face challenges in capturing accurate 3D images at high speeds and achieving a large depth of field, particularly in the electronics manufacturing industry, where complex assembly tasks require precise vision and inspection capabilities.
Innovation Solution
A 3D machine-vision system is designed with two pairs of cameras, utilizing a laser-based structured-light projector that includes a digital micromirror device and a beam expander, along with tilted image sensors, to enhance image capturing speed and depth of field, while reducing specular reflection through dual illumination setups.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single camera is used for 3D imaging, then the device complexity is reduced, but the depth of field is insufficient
Solution Approach 1:
The imaging system is segmented into multiple specialized camera pairs: first camera pair optimized for structured light capture, second camera pair for normal illumination capture, and third camera pair for specular reflection reduction. Each pair targets specific depth ranges, collectively achieving extended depth of field without requiring excessive complexity in a single camera system.
Solution Approach 2:
The patent introduces temporal dimension by capturing images at different time points with different illumination conditions. The first camera pair captures structured light patterns, the second captures normal illumination, and the third captures specular reflections. By combining information across time and illumination dimensions, the system achieves extended depth of field.
2Productivity
If high-speed image capturing is implemented, then productivity is improved, but measurement precision deteriorates
Solution Approach 1:
The system performs preliminary actions by capturing multiple images under different illumination conditions (structured light, normal light, specular reflections) before final 3D reconstruction. This preliminary multi-condition capture enables high-speed processing while maintaining precision, as the decomposition of imaging tasks across multiple specialized cameras allows parallel processing.
Solution Approach 2:
The patent uses multiple camera pairs as copies, each specialized for different imaging functions. The first camera pair copies the imaging function for structured light, the second for normal illumination, and the third for specular reflection detection. This copying approach enables high-speed parallel capture while maintaining high measurement precision through specialized optimization of each copy.
3Manufacturing precision
If specular reflection is reduced through image processing, then manufacturing precision is improved, but loss of time increases
Solution Approach 1:
The third camera pair performs preliminary capture of specular reflection components under normal illumination. By separating specular reflection capture from the main structured light imaging, the system eliminates the need for time-consuming post-processing to remove specular highlights. The preliminary separation enables direct use of captured images for inspection, reducing processing time while maintaining manufacturing precision.
Solution Approach 2:
The system extracts specular reflection information using the third camera pair dedicated to capturing normal illumination images. By taking out the specular reflection component as a separate imaging task, the main structured light imaging pipeline remains unaffected and can proceed at high speed. The extracted specular information is then used to improve manufacturing precision by compensating for reflection artifacts.
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 high-speed image capturing and increased depth of field, enabling accurate 3D imaging and reducing specular reflections, thereby improving the precision and efficiency of robotic assembly tasks in electronics manufacturing.
Implementation Method 1
a collimator for collimating light emitted by the light source
Implementation Method 2
a digital micromirror device (DMD) for reflecting the collimated light
Implementation Method 3
a beam expander for expanding a light beam reflected off the DMD
Implementation Method 4
The structured-light projector can include a laser-based light source
Data Source
AI summary
One embodiment can provide a machine-vision system. The machine-vision system can include a structured-light projector, a first camera positioned on a first side of the structured-light projector, and a second camera positioned on a second side of the structured-light projector. The first and second cameras are configured to capture images under illumination of the structured-light projector. The structured-light projector can include a laser-based light source.