Laser Autofocus Lens Positioning for Defocus Reduction
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Solution Overview
Problem
Existing autofocus systems in imaging devices face challenges such as prolonged search times for optimal focus, increased failure rates due to incorrect directional searches, and user experience issues with defocusing during the autofocus process, particularly in dynamic or multi-object environments.
Innovation Solution
The method involves capturing multiple frames, detecting changes in the scene using sensors like laser or dual cameras, estimating the optimal focus lens position based on distance data, and moving the lens towards this position while the scene is changing, initiating a fine autofocus search once stability is determined, thereby reducing defocus events and improving focus accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional autofocus search operations are used to find optimal lens position, then focus accuracy is achieved, but search time increases and defocus events occur during the search process
Solution Approach 1:
The system performs preliminary actions by detecting scene changes and pre-positioning the lens before initiating the autofocus search. By monitoring scene stability and preparing the lens position in advance, the system reduces the actual search time while maintaining focus accuracy.
Solution Approach 2:
The system continuously monitors scene stability and provides feedback to determine when to initiate autofocus search. This feedback mechanism allows the system to optimize search timing and reduce unnecessary search operations, thereby reducing search time while maintaining accuracy.
2Adaptability or versatility
If autofocus search operates in dynamic scenes, then continuous focusing capability is provided, but defocus events increase due to scene changes during search
Solution Approach 1:
The system dynamically adapts to scene changes by continuously monitoring scene stability and adjusting the autofocus search initiation accordingly. This dynamic approach allows the system to maintain focus stability in changing environments while preserving continuous focusing capability.
Solution Approach 2:
The system takes preliminary anti-action by detecting scene changes and delaying or adjusting autofocus search operations when scene instability is detected. This prevents defocus events caused by searching during unstable scenes while maintaining the ability to focus when conditions are favorable.
3Speed
If laser distance sensing is added to estimate lens position, then focus speed improves, but device complexity increases
Solution Approach 1:
The system uses laser distance sensing as an intermediary to estimate object distance and determine preliminary lens position. This intermediary measurement provides focus speed improvement by giving the system advance information about the required lens position, while the complexity is managed through integrated processing.
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
This approach significantly reduces defocus events by moving the lens closer to the optimal focus position before the autofocus search, enhancing the speed and accuracy of focusing, and improving overall image quality by minimizing the occurrence of defocusing during the preview phase.
Implementation Method 1
detecting a distance between the object and the imaging device for each of the image frames
Data Source
AI summary
Methods and imaging devices are disclosed for reducing defocus events occurring during autofocus search operations. For example, one method includes capturing a plurality of frames depicting a scene with an imaging device, selecting a portion of the scene of at least one frame that corresponds to an object of the scene, and detecting a change in the scene. The method further includes detecting a distance between the object and the imaging device for each of the plurality of frames, determining a lens position for each frame based on the determined distance of each frame and moving a lens toward the lens position of each frame while the scene continuously changes. The method also includes determining the scene is stable and initiating an autofocus search operation based on the determination that the scene is stable.