Autofocus Region Weighting for Misaligned Target Focus
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Solution Overview
Problem
Existing autofocus systems struggle to efficiently perform focusing calculations on specific regions of interest in imaging apparatuses, particularly when the target subject and portion are not aligned or oriented correctly, leading to suboptimal focus control.
Innovation Solution
An automatic focus control device that identifies a high contribution degree region within a specific region based on the target subject and portion, adjusting reduction magnification and contribution degrees to enhance focusing accuracy, even when the target is not aligned or oriented correctly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the entire specific region is used for focusing calculation, then the focusing calculation covers a broad area, but the focusing accuracy on the target portion deteriorates when the target is not aligned or oriented correctly
Solution Approach 1:
The patent divides the specific region into multiple regions with different contribution degrees (high contribution degree region and low contribution degree region) based on the detected target subject and target portion. This segmentation allows the system to selectively weight different areas during focusing calculation, prioritizing the target portion while still considering surrounding areas, thereby maintaining focusing accuracy even when the target is not perfectly aligned or oriented.
2Measurement precision
If the focusing calculation region is reduced to only the high contribution degree region, then the focusing accuracy on the target portion is improved, but the calculation robustness deteriorates
Solution Approach 1:
The patent assigns different contribution degrees (weights) to different regions within the specific region rather than uniformly including or excluding them. The high contribution degree region (containing the target portion) has a higher weight in the focusing calculation, while the low contribution degree region (peripheral areas) has a lower but non-zero weight. This local quality differentiation improves focusing accuracy on the target while maintaining calculation robustness through the contribution of surrounding areas.
3Measurement precision
If the high contribution degree region is reduced in size, then the focusing calculation is more precise on the target portion, but the calculation time increases due to more complex region processing
Solution Approach 1:
The patent performs preliminary detection of the target subject and target portion to identify the high contribution degree region before executing the focusing calculation. By pre-defining the region boundaries and contribution degrees based on target detection results, the system avoids complex real-time region processing during the focusing calculation itself, thereby maintaining high focusing precision while reducing overall calculation time.
Data Source
AI summary
An imaging apparatus performs focusing calculation for calculating a focusing position of a focus lens based on a signal for calculation read out from an imaging element. A focus adjustment unit includes a setting unit and a focusing calculation unit. A detection unit detects, from a signal for image generation, a rectangular region including a target portion of a target subject of the focusing calculation and a peripheral portion of the target portion. The setting unit is configured to set a high contribution degree region where a degree of contribution to the focusing calculation is higher than other regions in the rectangular region, based on a combination of the target subject and the target portion. The focusing calculation unit performs, in a case where the high contribution degree region is set, the focusing calculation in accordance with the setting.