Imaging Device Restoration Filter Selection for Temperature Variation
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Solution Overview
Problem
Existing imaging devices face challenges in accurately determining subject distance due to lens barrel temperature variations, leading to incorrect restoration filter selection and overcorrection during image restoration processing, which degrades image resolution.
Innovation Solution
An imaging device that includes a first subject distance estimation unit, an estimation variation acquisition unit, and a restoration filter selection unit to calculate and adjust the subject distance, selecting a restoration filter corresponding to the infinity side closest to the estimated subject distance to prevent overcorrection and improve image resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a restoration filter is selected based on the focusing stop position of the focus lens, then the image restoration processing can be performed, but the subject distance measurement becomes incorrect when the lens barrel characteristic varies by temperature
Solution Approach 1:
The patent introduces a subject distance estimation unit that acts as an intermediary between the focus lens position detection and the restoration filter selection. This unit calculates the subject distance based on the focusing stop position while compensating for temperature variations through pre-stored lens barrel characteristic data, thereby mediating the inaccurate measurement to produce a corrected subject distance value for filter selection
Solution Approach 2:
The patent changes the parameter used for subject distance determination from the raw focusing stop position to a corrected subject distance value. The correction is achieved by applying temperature compensation using pre-stored lens barrel characteristics, transforming the inaccurate position-based measurement into an accurate distance value that accounts for thermal expansion effects
2Adaptability or versatility
If the focusing stop position of the focus lens is used to determine subject distance, then the restoration filter can be selected, but the accuracy of focusing determination decreases when the contrast of the subject is low
Solution Approach 1:
The patent performs preliminary action by pre-storing lens barrel characteristics for multiple temperatures in advance. These pre-stored characteristics are then used to correct the subject distance estimation regardless of the actual focusing conditions, ensuring reliable filter selection even when contrast detection accuracy is poor
3Productivity
If an inappropriate restoration filter is used, then the restoration processing can be performed, but overcorrection occurs and resolution is degraded
Solution Approach 1:
The patent implements feedback by using the corrected subject distance value (which accounts for temperature effects and estimation variations) to select the appropriate restoration filter. This feedback mechanism ensures that the filter selection is based on an accurate representation of the actual subject distance, preventing overcorrection and maintaining image resolution
Data Source
AI summary
According to the present invention, even if variation (estimation variation) is caused in a subject distance estimated at the time of imaging when restoration processing of a taken image is performed using a restoration filter corresponding to the subject distance, since an optimal restoration filter that conforms to a subject distance taking into account the maximum infinity-side estimation variation and does not cause overcorrection is selected, it is possible to prevent resolution degradation due to overcorrection and achieve the improvement of resolution by the restoration filter.