Autofocus Jitter Filtering via Gyroscope Offset
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Solution Overview
Problem
Existing autofocus systems in imaging devices can result in out-of-focus images due to jitter, as they may incorrectly identify local maximum focus values caused by external interference as the optimal focus position.
Innovation Solution
A focusing method that employs contrast-detection autofocus mode, utilizing a gyroscope to measure rotation angular velocity and filter out focus values affected by jitter, ensuring only valid focus values are used to determine the optimal focus position within a preset offset range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If contrast-detection autofocus mode is used to determine focus position, then focusing speed is improved, but focusing accuracy deteriorates due to jitter-induced false peak detection
Solution Approach 1:
An offset value representing jitter magnitude is introduced as an intermediary parameter to mediate between the focus value and the determination of optimal focus position. The offset value acts as a threshold that filters out false peaks caused by jitter, allowing the system to maintain fast contrast-detection autofocus while improving accuracy by ignoring focus values that exceed the jitter threshold
Solution Approach 2:
The system changes the parameter used for focus determination from solely relying on focus value magnitude to considering both focus value and offset value. By introducing the offset value parameter that quantifies jitter, the system transforms the single-parameter optimization problem into a two-parameter evaluation, enabling accurate focus detection even in the presence of jitter
2Ease of operation
If focus determination is based on maximum focus value, then focusing simplicity is improved, but reliability deteriorates due to jitter causing out-of-focus conditions
Solution Approach 1:
The offset value serves as an intermediary that preserves the simplicity of maximum-based focus determination while adding reliability. Instead of complicating the focus determination logic, the system simply adds a jitter threshold check: if the offset value exceeds the preset threshold, the focus determination is invalidated. This maintains operational simplicity while significantly improving reliability under jitter conditions
Solution Approach 2:
The harmful effect of jitter is extracted and isolated into a separate offset value parameter. By separating the jitter measurement from the focus value calculation, the system can independently evaluate and filter out jitter-induced errors without affecting the simplicity of the main focus determination process. The offset value is extracted as a distinct metric that can be compared against a threshold to reject unreliable focus measurements
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
This approach prevents out-of-focus issues by accurately identifying and filtering out focus values distorted by jitter, allowing for precise focusing on the target object.
Implementation Method 1
obtain a current offset value of the imaging apparatus correspondingly, wherein the offset value is a rotation angular velocity obtained by a gyroscope
Data Source
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AI summary
The present disclosure relates to a focusing method, a focusing apparatus, a computer readable storage medium and a terminal. The focusing method includes: controlling an imaging apparatus to employ a contrast-detection autofocus mode to focus on a target object to be captured; obtaining a current focus value and a current offset value of the imaging apparatus correspondingly each time the imaging apparatus is driven to move; obtaining a plurality of focus values of validity from the obtained focus values according to the obtained offset values; and determining a maximum value from the plurality of focus values of validity.