Progressive Auto-Focus Lens Control Method
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Solution Overview
Problem
Conventional auto-focus methods in digital cameras often result in prolonged focus times and unstable image capture due to inaccurate in-focus location calculations, especially when objects move or environmental factors like low light affect the process, leading to excessive or insufficient lens movement and a poor user experience.
Innovation Solution
A progressive auto-focus method that calculates the in-focus location and distance for the lens, transforming it into smaller progressive distances using a transform table or confidence values, allowing the lens to move progressively to the in-focus point, avoiding back-and-forth movements and maintaining image stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the lens is moved all at once to the calculated in-focus location, then the focus operation is completed quickly, but the lens may move too much or too little requiring back-and-forth adjustments which prolongs focus time
Solution Approach 1:
The patent divides the total in-focus distance into multiple progressive distances, moving the lens in steps rather than all at once. The lens control circuit calculates a progressive distance that is smaller than the total in-focus distance, moves the lens by this progressive distance, and then repeats the process until the optical system is in focus. This segmentation allows quick initial movement while enabling incremental adjustments for accurate focusing.
2Loss of time
If the lens is moved all at once to the calculated in-focus location, then the focus operation is completed quickly, but the suddenly clear and suddenly blurred image displayed during the focus process influences user experience
Solution Approach 1:
By segmenting the lens movement into progressive steps, the patent avoids the sudden clear-blur transition caused by single-step movement. The progressive distance approach allows the image to transition gradually through intermediate focus states, providing a smoother visual experience while still completing focus quickly.
Solution Approach 2:
The patent implements a dynamic focus process where the lens control circuit continuously adjusts the lens position based on real-time feedback from the focus circuit. The system dynamically determines whether to continue moving the lens by progressively repeating the calculation and movement process, creating a smooth adaptive transition rather than a static single-step jump.
3Extent of automation
If the in-focus location is calculated using phase detection or infrared ranging, then the focus operation can be performed, but environmental factors like low light may cause inaccurate calculations
Solution Approach 1:
The patent implements a feedback mechanism where the focus circuit continuously monitors whether the optical system is in focus after each lens movement. The lens control circuit receives feedback from the focus circuit and determines whether to continue moving the lens by progressively repeating the process. This feedback loop ensures accurate focusing even when initial calculations are affected by environmental factors.
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 accelerates focus speed, reduces focus time, and enhances the user experience by maintaining image stability and preventing sudden blurring or clarity issues during the focus process, even when objects move or environmental factors are unfavorable.
Implementation Method 1
the focus circuit includes a phase detection circuit, and the step of calculating the in-focus location of the optical system and the in-focus distance for moving the optical system to the in-focus location by the focus circuit includes receiving a plurality of image signals captured by the focus detection pixels when the image sensor captures the image by the phase detection circuit, and calculating a phase difference between the image signals captured by each pair of the focus detection pixels by the phase detection circuit
Data Source
AI summary
An image pick-up apparatus and a progressive auto-focus method thereof are provided. The image pick-up apparatus includes an optical system, an image sensor, a focus circuit and a lens control circuit. In the method, an image is captured by using the image sensor and whether the optical system is in focus when the image sensor captures the image is determined by the focus circuit. If the optical system is out of focus, an in-focus location of the optical system and an in-focus distance for moving the optical system to the in-focus location are calculated by the focus circuit. The in-focus distance is transformed into a shorter progressive distance and the optical system is controlled by the lens control circuit to move by the progressive distance. Aforesaid steps are repeated until the optical system is in focus and the image captured by the image sensor is output.