Autofocus Control System for Power Reduction in Camera Modules
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Solution Overview
Problem
Handheld electronic devices with camera modules face significant power consumption issues due to continuous autofocus operations, leading to reduced battery life and undesirable delays between capturing an image and the user's intent to take a picture.
Innovation Solution
Implementing an intelligent autofocus method that analyzes the degree of change between successive frames to determine if autofocus is necessary, only running the autofocus routine when the change is below a predetermined threshold, thereby conserving power and reducing delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If continuous autofocus routine is run to reduce delay, then response speed is improved, but power consumption increases
Solution Approach 1:
The autofocus system dynamically adjusts its operation mode based on detected scene changes. When changes are detected, continuous autofocus is activated to reduce delay. When no changes are detected, autofocus is suspended to conserve power. This dynamic adaptation resolves the contradiction between speed and power consumption.
Solution Approach 2:
Instead of continuous operation, the system uses periodic frame analysis to detect scene changes. Autofocus is activated only during periods when changes are detected, creating a periodic on-demand operation pattern rather than continuous operation, thereby reducing overall power consumption while maintaining responsiveness.
2Measurement precision
If full autofocus scan is performed, then focus accuracy is improved, but time delay increases
Solution Approach 1:
The system performs preliminary detection of scene changes by analyzing frame differences before initiating a full autofocus scan. This preliminary action allows the system to determine whether a full scan is necessary, reducing unnecessary full scans and their associated delays while maintaining focus accuracy when needed.
Solution Approach 2:
Instead of always performing a complete autofocus scan, the system performs partial autofocus operations only when scene changes are detected. This partial action approach reduces the time delay associated with full scans while maintaining sufficient focus accuracy for changed regions.
3Use of energy by moving object
If autofocus is disabled to save power, then power consumption is reduced, but image quality deteriorates
Solution Approach 1:
The system continuously monitors frame changes and uses this feedback to determine when autofocus operations are necessary. This feedback mechanism ensures that autofocus is activated only when scene changes indicate it is needed to maintain image quality, preventing both unnecessary power consumption and quality deterioration.
Solution Approach 2:
The autofocus system serves itself by automatically detecting when its intervention is needed through frame change analysis. It activates itself only when necessary to maintain image quality, eliminating the need for continuous operation while preserving quality when required.
Data Source
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AI summary
A method and apparatus providing an autofocus routine in a camera apparatus having a processor is disclosed. The camera apparatus is adapted to detect a number of images and communicate image signals representative thereof to the processor. The method includes determining that a degree of change between a first image signal and a second image signal is below a predetermined threshold and responsive thereto, performing the autofocus routine.