Image Acquisition Geometry for Specular Reflection Object Inspection
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Solution Overview
Problem
Existing image acquisition devices struggle to efficiently detect objects with a property of reflecting light on inspection targets due to difficulties in distinguishing specularly reflected light from diffused light.
Innovation Solution
The device employs a configuration where the straight line connecting the light irradiation unit center and the imaging lens optical axis is inclined by 2 to 120 degrees, and the solid angle of the light irradiation unit is set to 0 to 0.15 steradians, enhancing the ratio of specularly reflected light intensity over diffused light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the light irradiation unit uses a conventional configuration, then the inspection device can acquire general image data, but it cannot efficiently detect objects with light-reflecting properties due to insufficient distinction between specularly reflected light and diffused light
Solution Approach 1:
The patent changes the geometric parameters of the light irradiation unit by setting the straight line connecting the light irradiation unit center and the imaging lens optical axis intersection to be inclined at 2 to 120 degrees, and setting the solid angle to 0 to 0.15 steradians. These parameter changes enable efficient detection of light-reflecting objects by optimizing the ratio of specularly reflected light to diffused light.
2Illumination intensity
If the solid angle of the light irradiation unit is increased, then more light reaches the target object, but the ratio of specularly reflected light intensity to diffused light intensity decreases, reducing detection efficiency
Solution Approach 1:
The patent optimizes the solid angle parameter of the light irradiation unit to be 0 to 0.15 steradians, which creates an optimal balance between providing sufficient light intensity on the target object and maintaining a high ratio of specularly reflected light to diffused light for efficient detection of light-reflecting objects.
3Device complexity
If the inclination angle of the light irradiation unit is set to 0 degrees (parallel to optical axis), then the setup is simple, but the specularly reflected light cannot be efficiently directed to the imaging device
Solution Approach 1:
The patent introduces asymmetry by setting the straight line connecting the light irradiation unit center and the imaging lens optical axis intersection to be inclined at 2 to 120 degrees relative to the optical axis. This asymmetric configuration enables the specularly reflected light to be efficiently directed toward the imaging device, resolving the limitation of parallel alignment.
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 efficient detection of light-reflecting objects by increasing the intensity ratio of specularly reflected light, enabling accurate image data acquisition.
Implementation Method 1
an imaging device that detects light that is specularly reflected by the target object in the light
Data Source
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AI summary
An image acquisition device 1 includes an illumination device 2 that irradiates a target object S with light from a range of a light irradiation unit 2a, and an imaging device 7 that detects light that is specularly reflected by the target object S in the light, via an imaging lens 7a, in which a straight line connecting a center of the light irradiation unit 2a and an intersection between an optical axis of the imaging lens 7a and the target object S is set to be inclined by 2 degrees or more and 120 degrees or less with respect to the optical axis, and a solid angle of the light irradiation unit 2a as viewed from the intersection is set to 0 steradians or more and 0.15 steradians or less.