Lens Control Apparatus for Moving Subject Focus Tracking
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Solution Overview
Problem
Existing camera systems face challenges in maintaining image quality when tracking moving subjects, as they often experience time lags and blurring due to temporary focus adjustments, especially during video shooting.
Innovation Solution
A lens control apparatus and method that includes a focus detection unit, a control unit, and a moving subject determination unit, which dynamically adjusts the focus lens drive based on defocus amounts and subject movement, allowing continuous focus adjustment and preventing blurring by transitioning between focus modes accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the focus lens is temporarily stopped upon detecting a focus result within the predetermined range, then the stability of the focus state is improved, but the responsiveness to moving subjects deteriorates, causing time lags and blurring
Solution Approach 1:
The patent applies dynamics by making the focus control system adaptable to different subject conditions. The control unit dynamically switches between two operational modes: a focusing stop mode for still subjects and a focus adjustment mode for moving subjects. This dynamic adaptation allows the system to optimize focus state stability when subjects are stationary while maintaining responsiveness when subjects are moving, thereby resolving the contradiction between stability and speed.
Solution Approach 2:
The patent changes the operational parameter of the focus lens control based on subject movement detection. When a moving subject is detected, the system changes from a mode that stops focus adjustment to a mode that continues focus adjustment. This parameter change allows the system to maintain both stability (by stopping when appropriate) and responsiveness (by continuing adjustment when needed), resolving the contradiction between focus state stability and tracking speed.
2Stability of the object's composition
If focus adjustment is temporarily stopped when a moving subject is determined to be in focus, then focus stability is improved, but image quality deteriorates due to blurring during time lag
Solution Approach 1:
The system dynamically adjusts its operational state based on real-time detection of subject movement. When a moving subject is detected, the control unit transitions to continuous focus adjustment mode, preventing the time lags and blurring that would otherwise occur. This dynamic behavior ensures that image quality is maintained for moving subjects while still allowing stability optimization for still subjects.
Solution Approach 2:
The patent implements feedback by continuously monitoring focus detection results and subject movement status. The control unit uses this feedback to determine whether to continue or stop focus adjustment. This feedback mechanism ensures that focus adjustment is maintained when needed for moving subjects, preventing blurring and maintaining image quality, while allowing stability optimization when subjects are stationary.
3Ease of operation
If a predetermined range for focus determination is used, then the ease of operation is improved, but the measurement precision of focus detection deteriorates for moving subjects
Solution Approach 1:
The patent applies local quality by implementing different focus determination criteria for different subject types. For still subjects, a predetermined range is used, providing simple operation. For moving subjects, continuous focus adjustment is performed without relying on the predetermined range, providing higher precision. This localized approach to different subject conditions resolves the contradiction between ease of operation and measurement precision.
Solution Approach 2:
The system dynamically selects the appropriate focus determination method based on subject movement detection. When a moving subject is detected, the system switches from using a fixed predetermined range to continuous focus adjustment mode. This dynamic selection allows the system to maintain simple operation for still subjects while achieving high precision for moving subjects, resolving the contradiction between ease of operation and measurement precision.
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
Improves image quality by ensuring continuous focus tracking of moving subjects, reducing time lags and blurring, and maintaining video quality even during rapid subject movements.
Implementation Method 1
an imaging element receiving and photoelectrically converting a pair of light rays with parallax
Data Source
AI summary
One or more lens control apparatuses, methods and storage mediums for use therewith are provided herein. In at least one lens control apparatus, a camera control unit determines that a subject is in focus if an amount of defocus is within a first range in a first mode where the camera control unit has not determined that the subject is a moving subject, and determines the focus state on a basis of the amount of defocus and a reversed state of a drive direction of a focus lens based on the amount of defocus in a second mode where the camera control unit has determined that the subject is a moving subject.