Dual Sensor Autofocusing for Microscope Speed and Accuracy
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Solution Overview
Problem
Conventional microscopes face challenges in achieving rapid and accurate autofocusing, especially when dealing with thin biological samples and variable sample thickness, due to limitations in existing autofocusing methods that either rely on a single reference point or require time-consuming multiple image acquisitions.
Innovation Solution
A digital optical microscope employs a primary image sensor and an auxiliary image sensor with different frame rates and pixel counts, where the auxiliary image sensor generates images at a faster rate and lower pixel count to quickly adjust the focal distance, allowing for rapid autofocusing without relying on the primary image sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional microscopes use a single reference point for autofocusing, then the autofocusing speed is improved, but the focusing accuracy deteriorates
Solution Approach 1:
The patent divides the autofocusing task into two independent parts: a primary image sensor for high-quality image capture and an auxiliary image sensor for rapid focusing. The auxiliary sensor captures multiple images at different focal distances to determine the optimal focus point, while the primary sensor captures the final high-quality image. This segmentation allows each sensor to specialize in its function, resolving the contradiction between speed and accuracy.
Solution Approach 2:
The auxiliary image sensor acts as an intermediary between the light source and the primary image sensor. It captures intermediate images at multiple focal planes to provide focus information, which then guides the primary sensor's positioning. This intermediary approach enables rapid focus determination without sacrificing the primary sensor's ability to capture high-quality images.
2Measurement precision
If conventional microscopes obtain multiple images at multiple focal distances for accurate autofocusing, then the focusing accuracy is improved, but the time delay increases
Solution Approach 1:
The auxiliary image sensor performs preliminary capture of multiple images at different focal distances before the primary image is taken. By pre-determining the optimal focal plane through rapid auxiliary imaging, the system eliminates the need to wait for multiple sequential captures during the actual imaging process, significantly reducing time delay while maintaining accuracy.
Solution Approach 2:
The auxiliary image sensor captures more images than strictly necessary for focus determination, using a lower-resolution sensor to oversample the focal plane. This excessive action allows the system to rapidly identify the optimal focus point through algorithms that analyze the captured images, achieving both speed and accuracy without requiring minimal captures.
3Device complexity
If the primary image sensor is used for both imaging and autofocusing, then the device complexity is reduced, but the image quality deteriorates due to time delays
Solution Approach 1:
The patent segments the imaging function into two separate sensors: a primary image sensor dedicated to high-quality image capture and an auxiliary image sensor dedicated to autofocusing. This segmentation allows each sensor to optimize its performance for its specific function, with the primary sensor capturing high-quality images without the time delays introduced by simultaneous autofocus operations.
Solution Approach 2:
The auxiliary image sensor creates a simplified copy or representation of the sample at lower resolution, using this copy to determine focus parameters. This copying approach allows rapid focus determination without requiring the primary high-resolution sensor to be occupied with autofocus operations, thereby maintaining image quality while reducing the effective complexity through functional specialization.
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 enables rapid and accurate autofocusing, reducing time delays and improving image quality by using the auxiliary image sensor to determine the optimal focal distance for the primary image sensor, suitable for high-throughput applications like pharmaceutical screening and microassembly.
Implementation Method 1
a beam splitter that splits light that is collected from a sample and passes through the objective lens into a primary light path and an auxiliary light path
Implementation Method 2
an objective lens, a beam splitter that splits light that is collected from a sample and passes through the objective lens
Data Source
AI summary
A digital optical microscope includes a primary image sensor that generates a primary image of a sample at a primary frame rate, an auxiliary image sensor that generates an auxiliary image of the sample at an auxiliary frame rate that is faster than the primary frame rate, and a controller that adjusts a focal distance between an objective lens and the sample along an optical axis in response to the auxiliary image, thereby autofocusing the primary image on the sample. The primary image sensor generates the primary image in response to the autofocusing.