Imaging Device Visual Parameter Calibration via Lens Position Ratio
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Solution Overview
Problem
Conventional automatic exposure and autofocus systems in cameras fail to maintain consistent luminance and contrast readings due to varying lens positions, leading to unsatisfactory image capture quality.
Innovation Solution
A method is introduced where the imaging device calculates a ratio of visual parameter difference to lens position difference between two predetermined positions, allowing for the determination of a target visual parameter that stabilizes luminance or contrast across different lens positions by updating the current visual parameter based on this ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional automatic exposure and autofocus systems are used, then the camera can automatically adjust aperture, shutter speed, and focus, but the luminance and contrast readings vary depending on lens position, leading to unsatisfactory image quality
Solution Approach 1:
The patent changes the parameter of luminance/contrast readings by introducing a calibration value that compensates for lens position variations. The system calculates a ratio between visual parameter difference and lens position difference, then uses this ratio to adjust readings dynamically based on current lens position, transforming the unreliable readings into calibrated accurate values
Solution Approach 2:
The patent implements a feedback mechanism where the system continuously monitors lens position and uses the pre-determined ratio to calculate calibration values that are fed back to adjust the luminance and contrast readings. This closed-loop feedback ensures readings remain accurate regardless of lens position changes
2Adaptability or versatility
If lens position is changed to achieve different focal lengths or focus distances, then the imaging device can capture images at various distances and focal lengths, but the luminance and contrast readings become inconsistent
Solution Approach 1:
The patent performs preliminary calibration by pre-determining the ratio between visual parameter difference and lens position difference at different focal lengths. This preliminary action creates a lookup table or calibration data that enables accurate readings without requiring real-time complex calculations when lens position changes
Solution Approach 2:
The system adjusts the reading parameter by applying a calibration value that is specific to the current lens position and focal length combination, transforming the inconsistent raw readings into accurate calibrated values while maintaining full lens position flexibility
Data Source
AI summary
A method of automatically calibrating a visual parameter, such as luminance or contrast, for an imaging device is disclosed. A ratio of visual parameter difference to lens position difference between two predetermined lens positions is pre-determined for a predetermined focal length. A target visual parameter is then obtained according to the pre-determined ratio, a current visual parameter and lens position difference between a current lens position and a target lens position. Finally, the current visual parameter is updated by the target visual parameter in an automatic mode.