Auto Focus Lens Direction Determination for Speed
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Solution Overview
Problem
Digital photographing apparatuses face challenges in auto focusing speed, leading to increased time consumption and potential missed opportunities for capturing images, as existing methods are inefficient in determining the correct focus lens movement direction.
Innovation Solution
An auto focusing method that determines the current position of the focus lens, assesses image blurring, and adjusts the motion direction based on whether the subject is at a close or far distance, allowing for precise and rapid focus adjustments by moving the focus lens within predetermined ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the focus lens moves through a large part of the possible positions to search for a high focus value, then the focusing accuracy is improved, but the auto focusing time increases
Solution Approach 1:
The patent applies preliminary action by using image recognition to pre-identify the subject and estimate its distance before the focus lens begins its search. This preliminary information allows the system to start the focus search from a more accurate initial position rather than scanning the entire range, thereby reducing the time required while maintaining focusing accuracy.
Solution Approach 2:
The patent implements feedback by continuously monitoring image blur levels during the focus search process and using this information to adjust the lens movement in real-time. The system evaluates image quality at each position and uses this feedback to determine whether to continue moving in the current direction or reverse direction, enabling a more efficient search that reaches the optimal focus position faster.
2Reliability
If the focus lens searches through all possible positions, then the reliability of finding the correct focus is improved, but the productivity of image capture is reduced
Solution Approach 1:
The system performs preliminary subject detection and distance estimation using image recognition algorithms before initiating the focus search. This preliminary action provides reliable information about the likely focus position, allowing the lens to start its search closer to the target position and reduce the overall search time while maintaining high reliability.
Solution Approach 2:
The patent applies partial action by limiting the focus search to a reduced range based on the estimated subject distance and uncertainty. Instead of scanning the entire possible lens position range, the system performs a focused search within a narrower window around the predicted position, achieving sufficient reliability with less time and motion.
3Speed
If the focus lens moves rapidly to save time, then the auto focusing speed is improved, but the precision of determining the correct focus position deteriorates
Solution Approach 1:
The patent implements dynamics by adjusting the lens movement speed based on the search phase and observed image quality. During the initial phase, the lens moves at higher speed to cover distance quickly, but when approaching the optimal focus region (indicated by improving image sharpness), the system automatically reduces speed to allow for more precise positioning and accurate determination of the peak focus position.
Solution Approach 2:
The system uses periodic evaluation of image blur levels at different lens positions to identify the focus trajectory. By sampling image quality at regular intervals and analyzing the pattern of blur changes, the system can detect when it is approaching the optimal focus position and adjust its movement accordingly, maintaining speed while ensuring precision.
Data Source
AI summary
An auto focusing method for improving an auto focusing speed by implementing auto focusing by determining a motion direction of the focus lens at a current position of the focus lens, a recording medium for recording the auto focusing method, and an auto focusing apparatus. The auto focusing method is implemented by determining a current position of a focus lens; determining whether a first image input at the current position of the focus lens has image blurring; if the current position of the focus lens is a position for long range focusing and the first image has image blurring, determining that a motion direction of the focus lens is toward longer range focusing; and if the current position of the focus lens is a position for long range focusing and the first image has image blurring, determining that the motion direction of the focus lens is toward closer range focusing.