Windshield Optical Defect Detection via Oblique Line Analysis
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Solution Overview
Problem
Existing methods for detecting optical defects in glass plates, particularly those with vertical components, are inadequate as they fail to effectively identify distortions caused by defects along a direction with a vertical component, leading to discomfort for drivers due to significant image distortion.
Innovation Solution
A method involving a target with essentially horizontal, continuous, and uniformly dark lines is used to detect optical defects in glass plates, particularly windshields, by observing the glass at a given angle with respect to a direction perpendicular to the plate, with the viewing angle being greater than or equal to 30°, and recording the observation by photography to analyze the thickness of the lines for defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing detection methods using inclined bands or diamond patterns are used, then certain distortions can be detected, but vertical defects or defects with vertical components cannot be detected
Solution Approach 1:
The invention changes the orientation of the detection pattern from diagonal/diamond shapes to essentially horizontal lines. This dimensional change in pattern orientation enables the detection of vertical defects that were previously invisible to diagonal band patterns, thereby expanding detection coverage while maintaining measurement precision.
2Ease of operation
If the viewing angle is perpendicular to the glass plate, then the observation is straightforward, but vertical defects are not highlighted
Solution Approach 1:
The invention modifies the viewing angle parameter from perpendicular (0°) to an oblique angle of at least 30° relative to the perpendicular direction. This parameter change causes vertical defects to manifest as apparent thickness variations in the horizontal lines, thereby improving defect detection accuracy while maintaining operational simplicity through automated photographic recording.
3Measurement precision
If horizontal lines are used in the pattern, then vertical defects can be detected through thickness variations, but the method requires oblique viewing angles
Solution Approach 1:
The invention replaces manual visual inspection at oblique angles with an automated photographic detection system. The system captures images at the required oblique viewing angles and automatically analyzes line thickness variations, thereby maintaining high measurement precision for vertical defect detection while eliminating the operational complexity of manual oblique viewing.
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 method effectively detects optical defects that can generate cuts in observed images, highlighting undulations in the glass, thereby improving the accuracy of distortion detection and reducing driver discomfort by identifying defects that previous methods missed.
Implementation Method 1
observation of the staff through said glass plate at a given angle with respect to a direction perpendicular to said plate
Implementation Method 2
recording the observation by photography to analyze the thickness of the lines for defects
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a method for detecting optical distortions in a glass plate, such as a windshield. The method comprises: observing, with a CCD sensor (8), through the windshield (2), and at an angle of incidence (ß - ? + 32) of greater than 45º, a target (6) consisting of a series of horizontal lines; and detecting the reductions in thickness, the deviations, and/or the vertical offsetting of the lines in the observed image. The presence of reductions in thickness, deviations, and/or vertical offsetting at specific points over a plurality of adjacent lines, said defects at the specific points being aligned in a straight, transverse line, is indicative of the presence of a defect capable of cutting off the objects observed through the glass plate.