Autofocus Z-Scan Parameter Adaptation for Optical Imaging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing autofocus methods are inefficient and slow due to overscanning, especially in medical visualization systems with variable optical zoom, as they typically use a small step width in scanning focal planes, which can lead to inaccuracies in finding the best focal plane, especially when the depth of field is low.
Innovation Solution
Adapting at least one parameter of the z-scan, such as scanning range, number of focal planes, or scanning frequency, based on the current optical zoom level and estimated working distance, allowing for a dynamic adjustment of the z-scan to quickly and accurately find the best focal plane by optimizing the scanning parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a small step width is used in scanning focal planes, then the accuracy of finding the best focal plane is improved, but the autofocus method becomes inefficient and slow due to overscanning
Solution Approach 1:
The patent applies dynamics by making the scanning parameters adaptive rather than fixed. The controller dynamically adjusts the step width and scanning range based on the current zoom level and depth of field conditions. When zoom is increased or depth of field decreases, the system automatically reduces step width to maintain accuracy, while when zoom is decreased or depth of field increases, it increases step width to improve speed. This dynamic adaptation resolves the contradiction between accuracy and efficiency.
Solution Approach 2:
The patent changes the parameters of the z-scan (scanning range, step width, number of focal planes) based on the current optical zoom level and estimated working distance. By adjusting these parameters dynamically, the system optimizes the balance between scanning accuracy and processing speed, avoiding both overscanning and underscanning conditions that would respectively cause inefficiency or inaccuracy.
2Productivity
If the spatial resolution is reduced in scanning focal planes to accelerate the method, then the speed is improved, but the best focal plane cannot be found with sufficient accuracy, especially with low depth of field
Solution Approach 1:
The system dynamically adjusts the scanning resolution (step width) based on real-time conditions including zoom level and depth of field. Rather than using a fixed low resolution to maintain speed, the system increases resolution automatically when depth of field is low or zoom is high, ensuring accuracy is maintained under critical conditions while still achieving speed improvements when conditions permit.
Solution Approach 2:
The patent changes the scanning parameters adaptively based on the current optical state. When the depth of field is low or zoom level is high, the system increases the number of scanned focal planes and reduces step width to maintain accuracy. When depth of field is sufficient, it reduces scanning density to improve speed, thus dynamically optimizing the parameter set for each operating condition.
3Device complexity
If a fixed scanning range is used, then the device complexity is reduced, but the autofocus method cannot adapt to changes in zoom level and working distance
Solution Approach 1:
The patent implements a dynamic scanning range that automatically adjusts based on the current zoom level and working distance. The controller modifies the z-scan parameters in real-time to match the optical conditions, allowing the system to adapt to different magnification levels and object distances without requiring multiple fixed scanning configurations or complex manual adjustment mechanisms.
Solution Approach 2:
The system changes the scanning parameters (range, step width, number of planes) as a function of the current optical zoom level and estimated working distance. This parameter adaptation allows a single autofocus system to effectively handle various working conditions, from wide-angle to telephoto zoom and from close-up to distant imaging, maintaining both simplicity and versatility.
Data Source
AI summary
To improve the accuracy and the speed of an autofocus method, using which a present best focal plane (13) may be found in an automated manner, which enables a best possible image quality for an object (3), which is located at a specific working distance (11) to an optical imaging system (1), it is provided that at least one parameter used during a z-scan (17) be adapted in an automated manner as a function of a presently set optical zoom level and/or a current estimated value of the working distance (11). During the z-scan (17), a present location of a focal plane (12) of the optical imaging system (1) is displaced within a scanning range (14) along an optical z-axis (8) of the imaging system (1), wherein the individual focal planes (12) are each evaluated to identify the best focal plane (13) among them.