Auto Focus System with Dynamic Reference Pattern Adjustment
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Solution Overview
Problem
Existing auto focus systems struggle to maintain accurate focus on moving subjects and adapt to changes in subject size due to changes in camera distance or focal length, leading to difficulties in detecting the target subject, especially when the reference pattern image becomes smaller or larger.
Innovation Solution
The auto focus system incorporates a reference pattern image acquisition range setting device, a position detecting device, and a size changing device to adjust the reference pattern frame's size and position based on the subject's movement and focal length changes, ensuring the target subject remains in focus by maintaining the image size within the reference pattern frame.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If the reference pattern image is stored initially and used for pattern matching, then the AF area can automatically follow the target subject, but the pattern matching fails when the subject's image size changes due to distance or focal length changes
Solution Approach 1:
The reference pattern image is dynamically updated based on the detected target subject image, allowing the system to adapt to changes in subject appearance, size, and position. This dynamic updating ensures the reference pattern remains accurate even when the subject moves or the camera parameters change.
Solution Approach 2:
The system uses feedback from the pattern matching process to continuously update the reference pattern image. By comparing the detected target subject with the reference pattern and using the result to update the reference, the system maintains accurate tracking despite changes in subject size or appearance.
2Adaptability or versatility
If the reference pattern image is updated by capturing from new photographing images, then the pattern can adapt to subject changes, but background images are included when the subject size becomes smaller
Solution Approach 1:
The system extracts only the relevant local region containing the target subject from the photographing image, rather than using the entire image. By carefully selecting and cropping the region around the detected target, the reference pattern contains only the subject without background contamination.
Solution Approach 2:
The photographing image is segmented to separate the target subject from the background. The system identifies the subject boundaries and extracts only the subject portion for the reference pattern, effectively isolating the target from surrounding background elements.
3Ease of operation
If a fixed rectangular AF area is set at the center of the photographing range, then the system is simple to operate, but it cannot follow moving target subjects
Solution Approach 1:
The AF area transitions from a fixed position to a dynamic position that automatically follows the target subject. The system continuously updates the AF area location based on target detection, enabling automatic tracking of moving subjects without requiring manual repositioning.
Solution Approach 2:
The system automatically adjusts the AF area position without operator intervention. By using automated pattern matching and target detection, the system serves itself in repositioning the focus area, eliminating the need for manual trackball or joystick manipulation.
4Adaptability or versatility
If the operator manually moves the AF area position using operating devices, then the target subject can be followed, but the operation requires trouble and attention
Solution Approach 1:
The system performs automatic target tracking without requiring operator manipulation. The pattern matching and AF area repositioning are executed autonomously by the system, freeing the operator from continuous manual control while maintaining accurate subject following.
Solution Approach 2:
The manual mechanical operation of moving the AF area using trackball or joystick is replaced with an automated image processing and pattern recognition system. This substitution eliminates the need for physical manipulation while achieving the same tracking function through computational methods.
Data Source
AI summary
The present invention provides an auto focus system capable of having an AF area which is a target range of auto focus (AF) automatically follow a follow-up target subject as a focusing target, wherein the system changes a size of a range for capturing an image of the follow-up target subject as a reference pattern image out of the range of a photographing image according to a target subject distance and a focal length of a photographing lens so as to appropriately perform detection of the image of the target subject and automatic follow-up of the AF area even in the case where the size of the image of the target subject in the photographing image of the camera changes such as the case where the distance between the camera and the follow-up target subject changes or the case where the focal length of the photographing lens (optical system of the camera) changes.