Camera Autofocus Using Multiple Distance-Based Focus Windows
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Solution Overview
Problem
Existing auto-focusing technologies in cameras face challenges in maintaining image quality when using small focus windows, particularly under conditions of low illumination or wide zoom, leading to reduced data availability and impaired focusing performance.
Innovation Solution
A camera device and method that utilizes multiple non-overlapping focus windows based on distance information, adjusting the number and placement of windows based on image type and conditions, such as low illumination or zoom-wide magnification, to enhance data utilization and focusing accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the focus window size is decreased to minimize image shaking at zoom wide position, then image stability is improved, but the amount of data for auto-focusing is reduced
Solution Approach 1:
The patent divides the image into multiple focus windows (first focus window and second focus window) instead of using a single small focus window. This segmentation allows the system to maintain small individual windows for stability while collectively gathering sufficient data across multiple windows for accurate auto-focusing.
2Device complexity
If a single focus window is used to simplify the focusing process, then device complexity is reduced, but auto-focusing performance deteriorates under low-illumination conditions
Solution Approach 1:
The patent dynamically adjusts the number and configuration of focus windows based on imaging conditions. Under low-illumination conditions, it uses multiple focus windows to improve reliability, while under normal conditions, it can use a single focus window to maintain simplicity. This dynamic adaptation resolves the contradiction between complexity and reliability.
3Quantity of substance
If multiple focus windows are used to increase data availability, then auto-focusing performance is improved, but device complexity increases
Solution Approach 1:
The patent applies local quality by setting different focus windows at different positions (first focus window at a first position, second focus window at a second position) with specific characteristics suited to their locations. Each window is optimized for its local imaging conditions, allowing the system to gather more data without uniformly increasing complexity across the entire system.
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
Improves auto-focusing performance by increasing data availability and accuracy, especially in low-illumination conditions and wide zoom scenarios, by using multiple focus windows strategically set based on distance information and image characteristics.
Implementation Method 1
The distance information may include at least one of an absolute distance obtained through a time of flight (ToF) of electromagnetic waves
Data Source
AI summary
A camera device includes: a lens configured to receive light incident from a subject; an image sensor configured to capture an image of the subject using the received light; a distance measurer configured to identify a plurality of positions having same distance information in the image; a window setter configured to set one or more focus windows in the image based on the plurality of positions; a focus position estimator configured to determine a focus position for capturing the image using pixels within the one or more focus windows; and a lens controller configured to control a position of the lens according to the determined focus position.