Microscope Scanner Focus Analysis for Adaptive Rescanning
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Solution Overview
Problem
Whole Slide Imaging scanners face challenges in maintaining focus across the entire tissue sample due to slide distortions and non-uniform tissue thickness, leading to areas outside the depth of focus that are unsuitable for diagnosis, and analyzing large image datasets is computationally intensive and time-consuming.
Innovation Solution
A method that generates focus control data during the imaging scan to analyze efficacy, allowing for adjustments in scanning parameters to improve focus and reduce computational demands, including pre-scan for low-resolution image selection and automated image analysis to identify sample areas and surface details.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If focus tracking mechanism is used to maintain focus across the entire tissue sample, then imaging quality is improved, but device complexity increases and focus accuracy may still be insufficient due to slide distortions and non-uniform tissue thickness
Solution Approach 1:
The patent replaces the mechanical focus tracking mechanism with an optical/electronic solution. Instead of physically adjusting the focal plane across the slide, the system captures images at multiple focal depths and uses software algorithms to select or combine the in-focus regions, thereby eliminating complex mechanical movement while maintaining focus accuracy
Solution Approach 2:
The patent adds the depth dimension to the imaging process by capturing images at multiple focal planes (z-stack). This allows the system to overcome the limited depth of field of the objective lens by sampling across the entire depth range of the tissue sample, effectively extending the usable depth of focus without mechanical adjustment
2Measurement precision
If complete image analysis is performed to assess scan quality, then diagnostic accuracy is improved, but processing time increases significantly
Solution Approach 1:
The patent divides the large image dataset into smaller regions or tiles for analysis. Instead of processing the entire slide image at once, the system analyzes individual regions independently, which can be processed in parallel, thereby maintaining comprehensive quality assessment while significantly reducing overall processing time
Solution Approach 2:
The patent performs analysis on a subset of key regions rather than the complete image. By focusing computational resources on critical areas (such as regions with detected anomalies or representative sample areas), the system achieves sufficient quality assessment without the full computational burden of analyzing every pixel across the entire slide
3Measurement precision
If high-resolution scanning is performed across the entire slide, then image quality is improved, but scanning time and data volume increase
Solution Approach 1:
The patent applies different imaging strategies to different regions of the slide. High-resolution scanning is performed only on regions containing tissue samples or areas of diagnostic interest, while background or empty regions are scanned at lower resolution or skipped entirely, thereby maintaining diagnostic quality while reducing overall scanning time and data volume
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
Enables rapid assessment of scan quality, allowing for timely correction of focus errors and optimization of scanning parameters to ensure high-quality imaging with minimal delay and reduced processing resources.
Implementation Method 1
acquiring an image of the target at each of a plurality of locations along the image scan path using the detector array
Implementation Method 2
acquiring an image of the target at each of a plurality of locations along the image scan path using the detector array
Implementation Method 3
a Whole Slide Imaging scanner typically has a focus tracking mechanism such as that described by U.S. Pat. No. 9,116,035 to achieve the correct focus across all of the tissue
Implementation Method 4
the natural aperture of the imaging limits the depth of focus to around 1 μm
Data Source
AI summary
A method is provided for operating a microscope scanner. A first imaging scan is performed of one or more area(s) of interest, AOI, on a target including a sample. This involves moving a detector array relative to the target along an image scan path and acquiring an image of the target at each of a plurality of locations along the image scan path. Focus control data is generated during the imaging scan by calculating a focus merit value at each said location along the image scan path. The focal height of the detector array is then adjusted along the image scan path based on the focus merit values. The efficacy of the first imaging scan is analysed using the focus control data and a change to one or more scanning parameters from the first imaging scan is determined, for the performance of a second imaging scan, based on this analysis.