Image Processing Shading Correction for Variable Exposure Times
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Solution Overview
Problem
Conventional microscope systems face challenges in achieving sufficient shading correction when exposure times differ between specimen photography and shading pattern acquisition.
Innovation Solution
An image processing apparatus that includes a γ property storing section, a shading data storing section, and a revised pattern calculating section to calculate and apply a revised shading pattern based on the ratio of exposure times, enabling optimal shading correction for image data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single shading pattern is used for all exposure times, then device complexity is reduced, but shading correction precision deteriorates when exposure times differ
Solution Approach 1:
The system performs preliminary calculation of a pre-correction pattern from the acquired shading pattern, then stores this pre-processed data for rapid revision during actual shooting. This preliminary preparation enables quick adaptation to different exposure times without requiring multiple pre-acquired shading patterns, thus reducing device complexity while maintaining correction precision.
Solution Approach 2:
The system changes the parameter of the shading pattern by calculating a revised pattern through gamma correction and exposure time ratio multiplication. This parameter transformation allows a single acquired shading pattern to be adapted to multiple exposure times, resolving the contradiction between using a single pattern (simplicity) and achieving precision across varying exposure conditions.
2Manufacturing precision
If multiple shading patterns are acquired for different exposure times, then shading correction precision is improved, but loss of time increases due to multiple acquisitions
Solution Approach 1:
Only one shading pattern is acquired in advance, and a pre-correction pattern is calculated from it. This preliminary action creates a reusable base pattern that can be quickly revised for different exposure times, eliminating the need to acquire multiple shading patterns and thus saving time while maintaining precision.
Solution Approach 2:
Instead of acquiring multiple original shading patterns, the system creates a copy (pre-correction pattern) from a single acquired pattern, then generates revised copies through computational adjustment. This copying approach reduces acquisition time while providing exposure-time-specific correction patterns.
3Measurement precision
If exposure time is increased to improve image quality, then image quality improves, but reliability of shading correction deteriorates due to exposure time mismatch
Solution Approach 1:
The system changes the exposure time parameter of the shading pattern through mathematical adjustment (multiplying by exposure time ratio and applying gamma correction). This allows the shading pattern to be adapted to any exposure time, ensuring reliable shading correction regardless of whether the exposure time is increased for improved image quality.
Solution Approach 2:
The shading correction system becomes dynamic by calculating revised patterns in real-time based on the actual exposure time used. Rather than being static and tied to a specific exposure time, the system adapts the shading pattern dynamically, ensuring reliability across varying exposure conditions that may be chosen to optimize image quality.
Data Source
AI summary
Optimal shading correction is achieved even when exposure times are different. An apparatus includes a section that stores a γ property of an image pickup device, a section that stores a shading pattern acquired by the image pickup device, and a first exposure time, a section that stores image data acquired by the image pickup device and a second exposure time, a section that calculates a pre-correction pattern, based on the stored shading pattern and the stored γ property, a section that calculates a revised pattern by performing γ correction for the calculated pre-correction pattern after multiplying the calculated pre-correction pattern by a ratio of the second exposure time to the first exposure time, and a section that performs shading correction for the stored image data by using the calculated revised pattern.