Video Stream Sharpening Filter for Autofocus Blurriness
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Solution Overview
Problem
Existing autofocus methods in video cameras result in some images in a stream being out of focus during the optimization process, causing visual annoyance and issues in image processing, as the focus adjustments lead to a pulsating blurriness and potential false positives in motion detection algorithms.
Innovation Solution
A method that involves acquiring images at different focus-motor positions, applying a sharpening filter to enhance the sharpness of images acquired during focus adjustments, and using a scaling operation to harmonize the field of view, thereby reducing the noticeable effects of the autofocus check and maintaining a consistent image stream.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If autofocus operation is performed by iteratively adjusting focus-motor position and acquiring images, then optimal focus is achieved, but some images in the stream become out of focus causing visual annoyance
Solution Approach 1:
A sharpening filter is introduced as an intermediary processing step between the image acquisition and display stages. The filter compensates for the blurriness caused by focus adjustments by enhancing edges and details, thereby mediating between the need for focus optimization and the desire to avoid visual annoyance.
Solution Approach 2:
The patent changes the parameter of image sharpness by applying different sharpening filter strengths based on the focus state. When images are acquired during focus adjustment, a stronger sharpening filter is applied to compensate for the expected blurriness, while normal images use standard processing.
2Object-affected harmful factors
If out of focus images are hidden from the operator, then visual annoyance is reduced, but potentially useful information is lost
Solution Approach 1:
Instead of hiding out-of-focus images, the patent extracts and processes them separately by applying enhanced sharpening filters. This allows the images to be retained and made usable, extracting the useful information from the potentially annoying blurriness through computational processing.
3Manufacturing precision
If sharpening filter is applied to images during focus adjustments, then image sharpness is enhanced, but processing complexity increases
Solution Approach 1:
The patent applies sharpening filters selectively only to images acquired during focus adjustment operations, rather than to all images continuously. This partial application reduces the overall processing burden while still addressing the specific problem of blurriness during autofocus.
Data Source
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AI summary
A method for processing images of an image stream acquired during an in-focus check, comprises acquiring a first image at a first focus-motor position and acquiring a second image at a second focus-motor position shifted in a first direction in relation to the first focus-motor position. The first sharpness value is calculated for the first image and a second sharpness value is calculated for the second image. A sharpening filter is applied on the second image, wherein the sharpening filter is enhanced in relation to any sharpening filter applied to the first image, thus enhancing the sharpness value thereof before adding to a display stream.