Digital Microscope Sensor Oversampling for Resolution Mismatch
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Solution Overview
Problem
Digital microscopes face undersampling issues due to the mismatch between the optical resolution of the objective lens and the image sensor, leading to suboptimal image quality and efficiency in imaging and processing.
Innovation Solution
A digital microscope design where the image sensor has a higher maximum image resolution than the objective lens, enabling localized oversampling and improved image quality through the use of a CMOS image sensor with a fine pixel pitch and high pixel count, along with adjustable magnification and optical components like lenses and filters, to achieve higher contrast and noise suppression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the image sensor resolution is increased to match or exceed the optical resolution of the objective lens, then the image quality and measurement precision are improved, but the device complexity and cost increase
Solution Approach 1:
The patent changes the key parameter of pixel pitch to 1.67 μm, which is smaller than the optical resolution limit, enabling the image sensor to capture finer details than traditional sensors matched to optical resolution. This parameter change resolves the contradiction by pushing the sensor resolution beyond the optical diffraction limit through advanced sensor design.
Solution Approach 2:
The patent performs preliminary optical conditioning through the objective lens to pre-focus and condition the light before it reaches the image sensor. This preliminary optical action ensures that the high-resolution sensor captures optimally focused images, maximizing the benefit of the fine pixel pitch while maintaining system simplicity.
2Measurement precision
If the pixel pitch is reduced to increase image sensor resolution, then the measurement precision is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent specifies a concrete pixel pitch parameter of 1.67 μm, which balances fine resolution with manufacturability. This specific parameter choice resolves the contradiction by providing a realistic manufacturing target that achieves sub-optical-resolution sampling without requiring impossible manufacturing precision.
Solution Approach 2:
The patent replaces mechanical/optical resolution limitations with electronic sensor resolution. Instead of relying on optical magnification and mechanical focusing alone, the system uses the electronic pixel array to achieve fine resolution, substituting optical-mechanical constraints with electronic detection capabilities.
3Productivity
If the refresh rate is increased to improve imaging speed, then the productivity is improved, but the image quality and signal-to-noise ratio deteriorate
Solution Approach 1:
The patent uses excessive sampling action by capturing images at a refresh rate that samples beyond the optical resolution limit. This excessive sampling in the temporal and spatial domains provides redundant information that can be processed to maintain high image quality even at high refresh rates, resolving the contradiction between speed and quality.
Solution Approach 2:
The system uses the high-resolution sensor data as feedback to optimize imaging parameters. By analyzing the captured images at high refresh rates, the system can adjust exposure, gain, and other parameters to maintain optimal signal-to-noise ratio while preserving high temporal resolution for dynamic imaging.
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 design results in higher-order oversampling, enabling rapid and aberration-free 3D microscopy, rapid autofocusing, high spectral resolution, and improved dynamic range, while allowing faster digitization of samples compared to prior art microscopes.
Implementation Method 1
an image sensor for converting the image, depicted on the image sensor by the objective lens, into an electrical signal
Data Source
AI summary
The present invention relates to a digital microscope that includes an objective lens for enlarged optical imaging of a sample in an image plane. An image with an optical resolution may be represented in the image plane by means of the objective lens. The microscope also includes an image sensor for converting the image, depicted on the image sensor by the objective lens, into an electrical signal. The image sensor includes a matrix of pixels by means of which a maximum image resolution of the image sensor is determined, which is finer than the optical resolution of the objective lens. The objective lens has a maximum magnification factor of at most 40. The optical resolution of the objective lens is defined as a minimum distance between two structures that are distinguishable in the image. The maximum image resolution of the image sensor is defined by a pixel pitch. A quotient of the minimum distance between two structures that are distinguishable in the image and the pixel pitch defines a scanning factor that is at least 5.