Camera System Focus Detection Pixel Illumination Correction
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Solution Overview
Problem
Existing camera systems face challenges in correcting focus detection pixel outputs due to changes in optical properties of the camera main body or interchangeable lenses, requiring frequent updates of correction coefficients.
Innovation Solution
A camera system configuration where the interchangeable lens stores pupil data and the camera main body stores illuminance correction data, allowing for automatic correction of focus detection pixel outputs without additional data updates, using equations to calculate corrected exit pupil positions and F-numbers based on image height, ensuring consistent illumination distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If correction coefficients are stored in the camera main body for each interchangeable lens, then focus detection accuracy is improved, but device complexity and data storage requirements increase
Solution Approach 1:
The correction coefficient data is segmented and distributed between two locations: pupil data (exit pupil position and F-number) is stored in the interchangeable lens, while illuminance correction data is stored in the camera main body. This segmentation reduces the burden on either component and simplifies the overall system architecture.
Solution Approach 2:
The pupil data is pre-stored in the interchangeable lens during lens manufacturing. When the lens is mounted, this preliminary data is automatically utilized by the camera main body to perform illuminance correction, eliminating the need for real-time measurement or complex calibration procedures.
2Measurement precision
If correction coefficients are updated for each optical property change, then focus detection accuracy is maintained, but loss of time and operational efficiency decrease
Solution Approach 1:
The pupil data characterizing the optical properties is pre-stored in the interchangeable lens during manufacturing. This eliminates the need for time-consuming updates when optical properties change, as the data is already available immediately upon lens attachment.
Solution Approach 2:
The interchangeable lens autonomously provides its own pupil data to the camera main body, eliminating the need for external calibration or manual updates. The system self-adjusts to different lenses automatically based on the embedded pupil data.
3Stability of the object's composition
If illuminance correction is applied to focus detection pixels, then non-uniformity of illuminance is reduced, but device complexity increases due to additional correction mechanisms
Solution Approach 1:
The illuminance correction process is segmented into two independent components: pupil data storage in the lens and illuminance correction data storage in the camera main body. This segmentation allows each component to remain relatively simple while achieving overall correction effectiveness.
Solution Approach 2:
The system utilizes parameter changes in the pupil data (exit pupil position and F-number) to dynamically adjust illuminance correction. By changing these parameters based on the attached lens, the system adapts to different optical configurations without requiring complex hardware modifications.
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
Enables accurate focus detection without the need for constant data updates, improving focus accuracy and reducing errors from optical property changes, while maintaining efficient operation across various lenses.
Implementation Method 1
an image sensor having a plurality of pixels which perform photoelectric conversion on luminous flux of a target object that has passed through the imaging lens
Data Source
Figure 1
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Figure 4~5
AI summary
A camera system (1) includes an interchangeable lens (100) and a camera main body (200). The interchangeable lens includes a lens side storage unit (108) that stores pupil related data according to an image height. The camera main body (200) includes an image sensor (208) including a plurality of imaging pixels for imaging, and a plurality of focus detection pixels for focus detection, a main body side storage unit (230) that stores correction data for correcting non-uniformity in illumination distribution by incident light to the focus detection pixel, and a correction unit (2222) that receives the pupil related data from the lens side storage unit (208), and corrects non-uniformity in illumination distribution of outputs of the focus detection pixels based on the correction data and the pupil related data.