Angle-Variable Illumination for Faster Height Profile Imaging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing materials testing techniques, such as shape from shading (SFS), are time-consuming and prone to errors due to the complexity and inefficiency in obtaining a sufficient number of images for reconstructing the elevation profile of a sample object.
Innovation Solution
An optical system with an illumination module that employs angularly variable illumination geometries and digital post-processing of multiple images using transfer functions to determine a result image, which includes a height profile of the sample object, allowing for the detection of anomalies and impurities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If shape from shading (SFS) technique is used to reconstruct elevation profile, then height profile can be obtained, but the process becomes time-consuming and error-prone due to complexity in obtaining sufficient images
Solution Approach 1:
The patent changes the illumination parameters (angular positions) to capture multiple images from different angles. By systematically varying the illumination angle and capturing images at discrete angular positions, the method obtains sufficient data for accurate height profile reconstruction while streamlining the process compared to traditional SFS approaches
Solution Approach 2:
The patent performs preliminary calibration by capturing images at multiple predetermined angular positions and storing these reference images. This preliminary action creates a database of illumination-angle-specific images that can be efficiently processed later to generate the height profile, reducing processing time during actual measurement
2Measurement precision
If multiple images are captured for height profile reconstruction, then measurement accuracy improves, but device complexity and processing time increase
Solution Approach 1:
The patent segments the illumination process into discrete angular positions, with each position captured by a dedicated illumination element or adjustable light source. The imaging process is segmented into multiple captures at different angles, with each segment processed independently through transfer functions before being combined to form the complete height profile
Solution Approach 2:
The patent employs dynamic illumination geometry where the illumination angle can be adjusted to different predetermined positions. This dynamic capability allows the system to capture images from multiple angles using the same imaging hardware, reducing device complexity compared to having multiple fixed cameras while still achieving accurate elevation reconstruction
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
The invention relates to an optical system (100), comprising an illumination module (111), which is designed to illuminate a sample object (180, 181) with at least one angle-variable illumination geometry. The optical system also comprises an imaging optics, which is designed to generate, on a detector (114), an image of the sample object (180, 181) illuminated with the at least one angle-variable illumination geometry, and the detector (114), which is designed to detect at least one representation of the sample object (180, 181) on the basis of the image. The optical system further comprises a control unit, which is designed to determine a result image on the basis of a transfer function and the at least one image.