Autofocus Control Apparatus with Variable Focus Detection Point Density
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Solution Overview
Problem
Conventional autofocus systems have a fixed focus target range and rely on a limited number of focus detection pixels, leading to decreased accuracy when focusing on small or moving subjects, as the focusing target range may not adequately cover the subject.
Innovation Solution
A control apparatus and method that dynamically adjust the density of focus detection points, concentrating them in a partial region corresponding to the subject and spacing them more sparsely in outer regions, to improve autofocus accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If focus detection pixels are uniformly distributed across the entire image pickup device, then the coverage area is maximized, but the density of focus detection points in specific regions is insufficient for accurate autofocus on small or moving subjects
Solution Approach 1:
The patent applies local quality by differentiating the density of focus detection points across different regions of the image pickup device. Specifically, a first density of focus detection points is used in a first region (where subjects are likely to be located) and a second, lower density is used in a second region. This allows high measurement precision in the first region for accurate autofocus on small or moving subjects, while reducing overall system complexity by not uniformly distributing detection points across the entire device surface.
2Measurement precision
If a fixed focusing target range is used, then the system is simple to implement, but the accuracy of autofocus decreases when the subject is small or moving
Solution Approach 1:
The patent implements dynamics by making the focusing target range adjustable rather than fixed. The system can dynamically change the position and size of the focusing target range based on detected subject characteristics. When a small or moving subject is detected, the system adjusts the focusing target range to appropriately cover the subject, thereby maintaining high autofocus accuracy while adapting to various shooting conditions.
3Measurement precision
If the focusing target range does not appropriately cover the subject, then the system is simpler to control, but autofocus accuracy decreases for small or moving subjects
Solution Approach 1:
The patent applies feedback by using subject detection results to automatically adjust the focusing target range. The system detects subjects and their characteristics (position, size, movement), then feeds this information back to adjust the focusing target range accordingly. This automated feedback mechanism maintains high autofocus accuracy for small or moving subjects while keeping the system easy to operate, as the adjustment occurs automatically without requiring manual user intervention.
Data Source
AI summary
Provided is a control apparatus including a focus detection control unit that sets a density of a focus detection point in a partial region specified, to be higher than a density of a focus detection point in a region excluding the partial region which corresponds to a position of an identified subject or a region specified by a user.