Optical Inspection Using Inverted Pattern Light for Defect Detection
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Solution Overview
Problem
Existing optical inspection methods face challenges in accurately projecting pattern light with a trigonometric function wave, necessitating a large number of pixels, which increases complexity and resource requirements.
Innovation Solution
The method employs pattern light with two modulation modes - a basic and an inverted modulation mode - to project spatially intensity-modulated patterns onto an object, capturing images in each mode, and generating a singular light-scattered image by subtracting pixel values to intensify singular regions, thereby enhancing inspection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pattern light with a trigonometric function wave is used to accurately represent the object property, then measurement precision is improved, but device complexity increases due to requiring a large number of pixels
Solution Approach 1:
The patent divides the pattern light projection into two separate modulation modes (first and second modulation modes) with opposite phase characteristics. By segmenting the inspection process into these distinct modes and capturing images separately for each mode, the system can process information more efficiently without requiring a single complex high-resolution trigonometric pattern, thus reducing the pixel count requirement while maintaining measurement precision
Solution Approach 2:
The patent employs inverted modulation modes where the phase characteristics are opposite to each other. By using inversion in the modulation pattern, the system creates complementary information that can be processed to extract object properties accurately, avoiding the need for complex trigonometric wave projections and reducing the required pixel density
2Measurement precision
If a large number of pixels are used to form pattern light, then measurement precision is improved, but loss of energy increases due to higher resource requirements
Solution Approach 1:
By segmenting the pattern light into two simpler modulation modes rather than using a single complex trigonometric wave, the patent reduces the computational and hardware resources required. This segmentation allows for lower pixel density while maintaining the ability to accurately acquire object properties, thereby reducing energy consumption
Solution Approach 2:
The patent changes the modulation parameters from complex trigonometric functions to simpler binary inversion patterns. This parameter change reduces the complexity of the projection system, allowing for fewer pixels and lower resource requirements while still achieving accurate object property measurement through the inverted modulation technique
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 allows for precise detection of singular regions such as cracks or foreign objects by intensifying their light scattering characteristics, improving inspection accuracy and reducing the need for high pixel density.
Implementation Method 1
projects pattern light with spatial intensity modulation representable by a trigonometric function, onto an object, captures an image of the object each time pattern light is projected
Implementation Method 2
captures an image of the object each time pattern light is projected, and acquires the property of the object from a plurality of images obtained by image capturing
Implementation Method 3
generating a singular light-scattered image in which a singular region including uniquely-scattered light that is extracted based at least on the first image and the second image is intensified
Data Source
AI summary
According to one embodiment, an optical inspection method includes projecting first pattern light in a first basic modulation mode that periodically changes in bright and dark, onto an object, acquiring a first image by capturing an image of the object onto which the first pattern light has been projected, projecting second pattern light in a first inverted modulation mode in which bright and dark are inverted with respect to the first basic modulation mode, onto the object, acquiring a second image by capturing an image of the object onto which the second pattern light has been projected, and generating a singular light-scattered image in which a singular region including uniquely-scattered light that is extracted based at least on the first image and the second image is intensified.