Autofocus Mechanism Using Motion Sensor Filtering
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Solution Overview
Problem
Existing autofocus systems in image capturing devices face challenges in continuously maintaining focus without distance information, especially in low-light conditions and when the device is unstable, leading to slower focus adjustment and potential image blur.
Innovation Solution
A continuous autofocus mechanism that performs autofocus scans, determines focus scores based on contrast, and adjusts lens positions using motion sensors to stabilize the device and filter unstable focus scores, allowing for refocusing without direct distance measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If passive autofocus systems use contrast detection to determine focus, then the system can operate without additional active sensors, but the focusing speed is slower especially in dim light
Solution Approach 1:
The system performs preliminary actions by using motion sensors to detect device stability before initiating autofocus, and by performing initial contrast detection scans to establish baseline focus scores. This preliminary assessment allows the system to prepare optimal autofocus parameters in advance, reducing the time required during actual focusing operations.
Solution Approach 2:
The patent replaces traditional mechanical or active sensing autofocus systems with a contrast-detection-based passive system enhanced by motion sensor data. Instead of using active distance measurement sensors or complex mechanical focus adjustment mechanisms, the system substitutes these with image contrast analysis combined with motion-induced focus score filtering, achieving reliable autofocus without additional active sensors.
2Productivity
If autofocus is performed when the device is unstable or shaking, then continuous focus maintenance is attempted, but focus accuracy decreases leading to blurred images
Solution Approach 1:
The system implements feedback by continuously monitoring device stability through motion sensors and using this information to modulate autofocus operations. Focus scores obtained during unstable periods are filtered or weighted differently based on motion data, and the system adjusts its focusing behavior in real-time based on the feedback from stability measurements, preventing inaccurate focus adjustments during shaking.
Solution Approach 2:
The autofocus system dynamically adapts its operation based on real-time stability conditions. When motion sensors detect device shaking, the system dynamically adjusts by deferring autofocus operations or filtering out focus scores obtained during unstable periods. This dynamic behavior allows the system to maintain continuous focus monitoring while selectively executing focus adjustments only when stability conditions are favorable.
3Measurement precision
If the system performs full autofocus scans frequently to ensure focus accuracy, then focus precision is maintained, but the processing time and energy consumption increase
Solution Approach 1:
Instead of performing complete autofocus scans at every interval, the system applies partial action by using motion sensor data to selectively filter and evaluate only the necessary portion of focus scores. When stability data indicates good conditions, the system performs more thorough focus assessments; when instability is detected, it performs minimal or deferred scanning. This partial action approach maintains focus precision while reducing unnecessary processing time and energy consumption.
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
Ensures proper focus between the image capturing device and subject, improving focus speed and stability, even in low-contrast scenes and during device movement, by using contrast-detect focusing and motion data to adjust lens positions effectively.
Implementation Method 1
one or more motion sensors can be used to determine whether the image capturing device is stable enough to perform autofocusing
Implementation Method 2
Contrast measurement is achieved by measuring contrast within a sensor field, through the lens. The intensity difference between adjacent pixels of the sensor naturally increases with correct image focus.
Data Source
AI summary
At least certain embodiments described herein provide a continuous autofocus mechanism for an image capturing device. The continuous autofocus mechanism can perform an autofocus scan for a lens of the image capturing device and obtain focus scores associated with the autofocus scan. The continuous autofocus mechanism can determine an acceptable band of focus scores based on the obtained focus scores. Next, the continuous autofocus mechanism can determine whether a current focus score is within the acceptable band of focus scores. A refocus scan may be performed if the current focus score is outside of the acceptable band of focus scores.