Dual-Lens Autofocus Convergence Using Incremental Step Adjustment
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Solution Overview
Problem
Existing autofocus methods in digital cameras often result in long focusing times and increased power usage due to the incremental nature of focus adjustments, especially when the initial focal distance is far from the focus point, leading to inefficient focusing processes.
Innovation Solution
A method utilizing two zoom lenses with different initial focus positions, where the image processor adjusts both lenses in tandem by moving them in increments of two focus positions to quickly converge on the optimal focus distance, reducing unnecessary focus steps and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If incremental focus adjustments are used to find the focus point, then the autofocus function can be achieved, but the focusing time increases and power consumption increases
Solution Approach 1:
The patent applies preliminary action by using contrast detection to evaluate the focus quality at the current lens position before performing incremental focus adjustments. This allows the system to determine whether the current position is already near the optimal focus point, thereby avoiding unnecessary incremental adjustments and reducing focusing time while maintaining reliable autofocus functionality
2Reliability
If incremental focus adjustments are used to find the focus point, then the autofocus function can be achieved, but power consumption increases
Solution Approach 1:
The patent applies preliminary action by performing contrast evaluation at the current lens position before initiating incremental focus adjustments. This preliminary check allows the system to avoid unnecessary motor actuations and processing cycles, thereby reducing power consumption while ensuring the autofocus function operates reliably when needed
3Adaptability or versatility
If the current focal distance is far from the focus point, then the incremental autofocus method can still search for focus, but the focussing time becomes very long
Solution Approach 1:
The patent applies feedback by continuously evaluating contrast at each lens position during the focus search and using this information to guide subsequent focus adjustments. This feedback mechanism allows the system to adapt to large initial focus errors by systematically searching through focus distances and converging on the optimal point more efficiently, maintaining adaptability while reducing focusing time compared to blind incremental searching
Data Source
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AI summary
The present disclosure provides a multi-lens device and method having improved autofocus. The method comprises: determining from a first focus value and second focus value whether a focus distance of a first lens or a focus distance of a second lens corresponds to a peak focus position; and adjusting the focus distance of the first lens and second lens when neither the focus distance of the first lens nor the focus distance of the second lens corresponds to the peak focus position.