Camera Focusing Device Lens Direction Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Autofocusing devices in cameras cannot detect the direction along the optical axis in which the lens position is offset relative to the focusing position, leading to inefficiencies in focus adjustment, especially when the subject moves or when filters like the ND filter are inserted.
Innovation Solution
A focusing device that includes an optical system, an image sensor, an edge detection unit, a differential value calculation unit, and a decision-making unit to determine the moving direction of the focusing lens based on edge strength differential values across color components, allowing for precise focus adjustment without requiring extensive contrast detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional contrast detection autofocus is used, then focus adjustment can be performed, but the direction of lens offset cannot be detected and extensive contrast detection is required
Solution Approach 1:
The patent segments the image signal into multiple color components (R, G, B) and performs edge detection separately for each color component. By calculating differential values for each color component's edge strength and comparing them, the system can determine the lens offset direction without requiring extensive contrast detection. This segmentation approach enables precise direction detection while simplifying the overall focus adjustment process.
2Measurement precision
If extensive contrast detection is performed for focus adjustment, then accurate focus can be achieved, but processing time increases
Solution Approach 1:
The patent performs preliminary edge detection on the image signal and calculates edge strength for multiple color components before focus adjustment. By pre-calculating differential values and determining the lens offset direction in advance, the system eliminates the need for extensive iterative contrast detection during focus adjustment. This preliminary action significantly reduces processing time while maintaining focus accuracy.
3Illumination intensity
If filter insertion is performed to adjust incident light, then exposure control is improved, but focus position shifts occur
Solution Approach 1:
The patent implements a feedback mechanism that detects changes in edge strength differential values after filter insertion and automatically adjusts the lens position to compensate for focus shifts. By continuously monitoring the differential values and comparing them before and after filter insertion, the system can detect focus position changes and perform corrective adjustments, thereby maintaining focus accuracy despite filter-induced shifts.
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
Enables rapid and accurate focus adjustment during live view imaging by determining the lens movement direction based on color component edge strength differentials, improving processing speed and maintaining focus without frequent adjustments.
Implementation Method 1
an optical system that includes a focusing lens; an image sensor that captures a subject image formed via the optical system
Implementation Method 2
an image sensor that captures a subject image formed via the optical system and outputs an image signal containing a plurality of color components
Data Source
AI summary
A focusing device comprises: an image capturing unit that captures a subject image formed via an optical system including a lens for executing focus adjustment and outputs an output signal; an edge detection unit that detects an edge signal among the output signal in correspondence to each color component among a plurality of color components contained in an image based upon the output signal; a calculation unit that calculates edge differential values each of which is a differential value of the edge signal in correspondence to the each color component; and a control unit that controls a moving direction along which the lens is to move based upon a comparison of the edge differential values.