Active Autofocus Window for Portable Imaging Devices
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Solution Overview
Problem
Existing autofocusing systems in portable imaging devices are too slow to capture fast-changing events in focus, often resulting in out-of-focus images, and require precise aiming of a focus window, which may not guarantee the desired object is in focus.
Innovation Solution
A method for portable imaging devices that involves moving a movable focusing frame on a display to identify an area of interest, analyzing the image within the frame to determine the optimal focus setting, and applying that setting to the entire image, using techniques such as plenoptic camera settings or wavefront coding to achieve focus at a desired depth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional mechanical autofocus systems are used, then focusing accuracy can be achieved, but the focusing speed is too slow to capture fast-changing events
Solution Approach 1:
The patent replaces the mechanical autofocus system with a computational approach. Multiple images captured at different focal depths are processed using image processing algorithms to generate a single composite image with extended depth of field. This substitution eliminates mechanical moving parts and achieves instantaneous focusing without mechanical adjustment delays.
Solution Approach 2:
The system performs preliminary capture of multiple images at different focal depths simultaneously or in rapid succession before the final image processing. By capturing all necessary focal planes in advance, the system eliminates the need for sequential mechanical adjustment during the shooting moment, enabling fast capture of fast-changing events.
2Ease of operation
If a focus window is used for manual autofocus, then focusing control is provided, but precise aiming is required which complicates the operation
Solution Approach 1:
The system automatically processes multiple captured images through computational algorithms to generate the final focused image. The user simply captures images without needing to manually adjust focus or precisely aim a focus window. The computational system performs the focusing task itself, eliminating the need for user intervention in focus adjustment and removing the requirement for precise aiming.
3Measurement precision
If a smaller aperture is used to increase depth of field, then more of the image is in focus, but light intake is reduced
Solution Approach 1:
The system changes the parameter of aperture size to a larger opening to maximize light intake. Instead of relying on a small aperture for depth of field, the computational method processes multiple images captured at different focal depths to achieve extended depth of field. This parameter change allows the aperture to be opened wider, improving light intake and signal-to-noise ratio while maintaining deep focus through computational processing.
Data Source
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AI summary
The present invention provides a method for changing the depth at which an image is focused in a portable imaging device (10). In addition, the invention provides an imaging device for this purpose. The imaging device (10) comprises an image recording arrangement (24) comprising a lens system and an image sensor for recording images, and a display arrangement (22) for presentation of the recorded images. The method comprises the step of moving a movable focusing frame (400) covering a part of a recorded image presented on the display (22) so as to identify an area of interest in the presented image; analyzing the image within the frame (400) to obtain a setting required to focus the image within the frame (400); applying the obtained setting to the full presented image so as to focus the presented image at the depth defined by the current position of the movable focusing frame (400).