Lens Control Apparatus Zoom Speed Defocus Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional lens control systems during zooming struggle to maintain a focus state change inconspicuously, leading to potential image blur due to reduced focus lens responsiveness, especially at high zoom speeds or low frame rates where focus detection is less frequent.
Innovation Solution
A lens control apparatus with a correction unit that adjusts the defocus amount based on zoom speed and frame rate, using cam locus data to optimize focus lens positioning and reduce responsiveness accordingly, ensuring timely focus adjustment without causing noticeable focus state changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the focus lens responsiveness is reduced to make focus state change inconspicuous, then the focus state change becomes less noticeable, but the focus lens may not reach the focusing position in time when focus detection is less frequent
Solution Approach 1:
The patent applies dynamics by making the focus lens driving speed variable rather than fixed. The control unit adjusts the driving speed based on real-time zoom lens position and zoom speed, allowing the system to optimize focus adjustment timing under different zoom conditions. This dynamic adjustment resolves the contradiction by enabling timely focus positioning when needed while maintaining smooth transitions when appropriate.
Solution Approach 2:
The patent changes the parameter of focus lens driving speed based on zoom lens position and zoom speed. By calculating appropriate driving speeds that consider the current zoom state, the system can adjust focus responsiveness dynamically. This parameter change approach allows the focus lens to reach positioning targets timely during certain zoom conditions while maintaining inconspicuous focus changes during other conditions.
2Productivity
If focus detection is performed less frequently at high zoom speeds, then the processing load is reduced, but the focus lens may not be adjusted in time leading to significant image blur
Solution Approach 1:
The patent applies preliminary action by calculating and setting the target focus lens position in advance based on predicted zoom lens position and zoom speed. The control unit determines appropriate driving speeds before the focus adjustment is executed, allowing the system to prepare focus positioning strategies proactively. This ensures timely focus adjustment even when focus detection frequency is reduced during high-speed zooming.
Solution Approach 2:
The patent dynamically adjusts the focus detection and control strategy based on zoom speed. When zoom speed is high, the system modifies its approach by calculating target positions and driving speeds that account for the reduced detection frequency, ensuring focus adjustments are timed appropriately. This dynamic adaptation resolves the contradiction between reduced processing frequency and maintained focus timeliness.
3Adaptability or versatility
If focus detection is performed using signals from image sensor, then focus detection can be integrated with image capture, but the focus detection frequency is limited by the image sensor frame rate
Solution Approach 1:
The patent applies universality by using the image sensor to serve dual purposes: both image capture and focus detection. The same image sensor signals are processed for both functions, eliminating the need for separate focus detection hardware. This multi-functional approach allows focus detection to be integrated seamlessly with image capture operations.
Solution Approach 2:
The patent changes the processing approach by calculating target focus lens positions and driving speeds based on the available image sensor frame rate. By adapting the focus control parameters to match the sensor's temporal characteristics, the system maximizes the utility of the integrated approach while working within the frame rate constraints to maintain effective focus adjustment timing.
Data Source
AI summary
A lens control apparatus and a control method thereof are disclosed. The lens control apparatus includes a microprocessor which obtains a correction defocus amount so that the correction defocus amount obtained by the microprocessor when a zoom speed is a first speed is greater than the correction defocus amount obtained by the microprocessor when a zoom speed is a second speed which is less than the first speed.