Slide-Scanning Focus Mapping With Tilted Line-Scan Cameras
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Solution Overview
Problem
Conventional slide-scanning systems face challenges in achieving real-time focusing, which is essential for reducing scanning time and ensuring high-quality image data acquisition.
Innovation Solution
A method involving a focus map creation using both imaging and tilted focusing line-scan cameras to determine optimal focus points, with processes to remove outliers and adjust the objective lens position in real-time to maintain focus during scanning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional focusing methods are used in slide-scanning systems, then system complexity is reduced, but scanning time increases and image quality deteriorates
Solution Approach 1:
A dedicated focusing camera is introduced as an intermediary device to capture focus information separately from the main imaging camera. This focusing camera projects a focus pattern through the objective lens and detects focus quality, allowing the system to determine optimal focus points without complicating the main imaging path. The intermediary focusing camera enables real-time focusing while maintaining relatively simple system architecture.
Solution Approach 2:
The patent replaces traditional mechanical focusing methods with an optical-based focusing detection system. Instead of relying on mechanical movement and trial-and-error focusing, the system uses optical patterns captured by the focusing camera to dynamically determine focus quality and automatically adjust focus points, significantly reducing scanning time while maintaining system simplicity.
2Manufacturing precision
If real-time focusing is implemented using multiple cameras and focus maps, then image quality improves and scanning time reduces, but system complexity and processing requirements increase
Solution Approach 1:
The system segments the focusing function from the main imaging function by using a dedicated focusing camera separate from the imaging camera. The focus map is segmented into discrete focus points that can be independently determined and stored. This segmentation allows the system to manage complexity by dividing the focusing task into manageable components: pattern projection, pattern capture, focus point determination, and map storage.
Solution Approach 2:
The system performs preliminary focusing by capturing focus patterns and determining optimal focus points before actual image acquisition. The focus map is created in advance, storing predetermined focus points that guide the scanning process. This preliminary action eliminates the need for real-time focusing adjustments during scanning, reducing overall system complexity while maintaining high image quality.
3Manufacturing precision
If focus points are continuously adjusted during scanning, then image quality improves, but processing time and computational load increase
Solution Approach 1:
The system determines all optimal focus points and creates the complete focus map before actual image acquisition begins. This preliminary determination of focus points eliminates the need for continuous processing during scanning, as the system simply follows the pre-established focus map. The computational load is concentrated in the preliminary phase, while the scanning phase operates efficiently with minimal processing time.
Solution Approach 2:
The system skips continuous focus adjustments during scanning by using the pre-determined focus map. Instead of analyzing and adjusting focus for every frame during acquisition, the system rapidly moves through the scanning process using the stored focus points, significantly reducing processing time while maintaining focus precision through the predetermined map.
4Manufacturing precision
If outlier focus points are removed and restriping is performed, then image quality improves, but scanning time increases
Solution Approach 1:
The system implements feedback by analyzing the focus map to identify and remove outlier focus points that would degrade image quality. This feedback mechanism allows the system to detect problematic focus points and correct them through selective restriping, improving overall image quality while minimizing the impact on scanning efficiency by only reprocessing affected areas rather than the entire scan.
Data Source
AI summary
Real-time focusing in a slide-scanning system. In an embodiment, focus points are added to an initialized focus map while acquiring a plurality of image stripes of a sample on a glass slide. For each image stripe, a plurality of frames, collectively representing the image stripe, may be acquired using both an imaging line-scan camera and a tilted focusing line-scan camera. Focus points, representing positions of best focus for trusted frames, are added to the focus map. Outlying focus points are removed from the focus map. In some cases, one or more image stripes may be reacquired. Finally, the image stripes are assembled into a composite image of the sample.