Imaging Device Autofocus Control for Point Light Sources
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Solution Overview
Problem
Existing imaging devices face challenges in accurately performing autofocus processing, especially in low-light conditions where point light sources dominate, as the hill climbing AF technique struggles to determine the in-focus position due to low contrast and reduced sensitivity caused by pixel addition and filtering methods.
Innovation Solution
An imaging device with an autofocus detector, a point light source detector, and a filter selection section that adjusts the driving conditions and filter settings based on image data analysis to enhance sensitivity and accurately determine the focus position, even in environments with point light sources and people.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If pixel addition and filtering methods are used to increase sensitivity in low-light conditions, then sensitivity is improved, but autofocus accuracy deteriorates due to low contrast and reduced detail
Solution Approach 1:
The imaging device segments the image data processing by applying different filter types (first filter for general sensitivity enhancement, second filter for autofocus processing) and performs pixel addition selectively for different purposes, allowing sensitivity improvement without compromising autofocus accuracy
Solution Approach 2:
Different processing qualities are applied to different parts of the image data: pixel addition and first filtering are applied to enhance sensitivity for low-light imaging, while original or differently filtered image data is used for autofocus processing to maintain contrast and detail information
2Extent of automation
If hill climbing AF technique is used for autofocus processing, then autofocus automation is achieved, but autofocus accuracy deteriorates in night scenes with point light sources due to low contrast
Solution Approach 1:
The system changes the parameters of image data processing by selecting different filter types and pixel addition levels based on the detected scene conditions, particularly adapting to night scenes with point light sources to maintain sufficient contrast for accurate autofocus
3Use of energy by moving object
If multiple driving conditions are used for imaging element operation, then sensitivity can be optimized for different conditions, but device complexity increases
Solution Approach 1:
The imaging device dynamically switches between multiple driving conditions based on the imaging situation, allowing sensitivity optimization for different conditions while managing complexity through conditional logic rather than permanent hardware configurations
Data Source
AI summary
An imaging device includes an imaging element configured to output an image signal in accordance with a target image acquired via an imaging lens, an autofocus detector configured to decide a focus in accordance with image data obtained from the image signal, a lens movement section configured to move the imaging lens on the basis of the focus, a driving condition setting section configured to set a driving condition of the imaging element, a point light source detector configured to determine whether or not the target is a point light source target on the basis of a brightness component of the image data, a target detector configured to detect a certain target from the image data, and a filter selection section configured to select a filter through which the image data is to be transmitted.