Autofocus Triggering for Smooth Manual Focus Transitions
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional imaging apparatuses face challenges in maintaining a smooth and stable focus state, especially in scenes with multiple objects or poor visibility, leading to unstable focus changes during manual focusing and motion image capturing.
Innovation Solution
A control apparatus and imaging system that utilize a focus detector and controller to perform autofocus control based on phase difference between image signals, adjusting the focus lens position and aperture to maintain a smooth focus state by calculating defocus amounts, reliability, and correlation between image signals, allowing for continuous and stable focus adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the focus lens is moved to the in-focus position after driving is stopped, then the in-focus position can be accurately achieved, but the focus state change becomes unstable and cannot capture smooth images
Solution Approach 1:
The system calculates the in-focus position in advance during manual focusing operations and prepares the autofocus trigger conditions beforehand. When the focus lens approaches the calculated in-focus position, the system proactively triggers autofocus to maintain smooth focus state, preventing the instability caused by stopping and repositioning operations.
2Ease of operation
If manual focus operation is performed, then the user can focus on intended objects, but the driving speed of the focus lens fluctuates for each operation
Solution Approach 1:
The system continuously monitors the focus lens driving speed and position during manual focusing operations. By providing feedback on the current focus state and comparing it with the calculated in-focus position, the system dynamically adjusts the autofocus trigger conditions to maintain stable focus state changes while preserving user control.
3Stability of the object's composition
If autofocus is triggered when focus lens decelerates, then smooth focus state can be maintained, but the in-focus position may be exceeded or deceleration may occur at wrong positions for objects with deep depth of field
Solution Approach 1:
The system dynamically changes the autofocus trigger parameters based on the calculated in-focus position and current focus lens position. Instead of using fixed deceleration-based triggering, the system adjusts trigger conditions according to the relationship between current position and calculated in-focus position, ensuring accurate focusing while maintaining smooth focus state transitions.
4Stability of the object's composition
If the focus lens is continuously driven without stopping, then smooth focus state change can be achieved, but the in-focus position cannot be accurately reached without temporary stop operation
Solution Approach 1:
The system calculates the in-focus position in advance and sets trigger conditions that will activate autofocus when the focus lens approaches this pre-calculated position. This preliminary calculation allows the system to maintain continuous smooth driving while ensuring accurate in-focus positioning through proactive trigger activation.
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
The system achieves a smooth and stable focus state change during manual focusing, enhancing the quality of motion image capturing by accurately determining the in-focus position and adjusting focus parameters accordingly, even in complex scenes or deep depth of field conditions.
Implementation Method 1
a focus detector detects a defocus amount based on a phase difference between a pair of image signals generated based on light beams having passed through different pupil areas in the imaging optical system
Data Source
Figure 1
Figure 2~3
Figure 4A~4C
AI summary
A control apparatus (20) includes a focus detector (204) configured to detect a defocus amount based on a phase difference between a pair of image signals generated based on light beams having passed through mutually different pupil areas in an imaging optical system, and a controller (207) configured to control a focus lens in the imaging optical system. The controller is configured to perform an autofocus control based on the defocus amount detected by the focus detector, and a manual focus control based on an operation of a user via an operation member. The controller performs the autofocus control when a change amount relating to a speed of the focus lens in the manual focus control falls within a predetermined range.