Dynamic Swathe Width Adjustment for Image Scanning Focus
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Solution Overview
Problem
Image scanning apparatuses face challenges in maintaining focus across the width of a swathe due to uneven biological samples, as the height variation exceeds the depth of focus and mechanical tolerances lead to tilting, making it impossible to dynamically adjust focus for the entire swathe width.
Innovation Solution
A method that uses scan lines to measure surface unevenness and sets a swathe width value to keep the swathe in focus by adjusting the imaging plane, allowing for focused imaging even when the sample is tilted, by calculating differential focus or using focus merit functions to determine optimal swathe width.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the swathe width is increased to improve scanning efficiency, then productivity increases, but the height variation of the sample across the swathe width exceeds the depth of focus, causing loss of focus
Solution Approach 1:
The patent implements dynamic focus adjustment during the acquisition of each swathe. The focus setting is continuously modified based on real-time measurement of the sample surface height along the scan length direction, enabling the system to maintain focus despite the increased swathe width that would otherwise cause focus loss across the broader area.
Solution Approach 2:
The system incorporates a feedback mechanism where the actual sample surface height is measured during scanning, and this measurement is used to adjust the focus setting dynamically. This closed-loop control ensures that the focus quality is maintained across the entire swathe width while allowing larger swathes to be scanned, thus improving productivity without sacrificing image quality.
2Loss of time
If the swathe width is increased to reduce the number of scans, then the scanning time is reduced, but mechanical tolerances cause the sample surface to be tilted relative to the imaging plane, making it impossible to keep the entire swathe in focus
Solution Approach 1:
The patent employs dynamic focus adjustment that operates throughout the acquisition of each swathe. As the scanner moves across the sample surface, the focus setting is continuously adapted to compensate for tilts and height variations caused by mechanical tolerances. This dynamic compensation allows wider swathes to be scanned in fewer passes, reducing total scanning time while maintaining focus uniformity across each swathe.
3Manufacturing precision
If dynamic focus adjustment is implemented along the scan length direction, then focus quality is improved, but it cannot compensate for height variations across the scan width direction at one time
Solution Approach 1:
The system extends dynamic focus adjustment to operate in both the scan length and scan width directions. By continuously monitoring sample height variations across the entire swathe area and adjusting focus dynamically, the system overcomes the limitation of static or one-dimensional focus control, enabling adaptability to height variations across the full swathe width while maintaining focus quality along the scan length.
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
This approach ensures that swathes are kept substantially in focus across their width, even when the sample is uneven, by dynamically adjusting the swathe width based on measured tilt and focus quality, enhancing image quality and scanning efficiency.
Implementation Method 1
an imaging lens 1 which focuses light originating from a sample located on a slide 6 onto a line scan detector 2
Implementation Method 2
The imaging lens 1 and the line scan detector 2 together make up an imaging system of the image scanning apparatus
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
Image scanning apparatus and method of operating an image scanning apparatus, the image scanning apparatus including a line scan detector and being configured to image a surface of an object mounted in the image scanning apparatus in a plurality of swathes, wherein each swathe is formed by a group of scan lines, each scan line being acquired using the scan line detector from a respective elongate region of the surface of the object extending in a scan width direction, wherein each group of scan lines is acquired whilst the object is moved relative to the scan line detector in a scan length direction.