Variable Attenuator Infrared Imaging Spectroscopy Dynamic Range
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Imaging spectrometers face challenges in accurately measuring the reflected mid-infrared light from samples due to the insufficient dynamic range of detectors, which limits the ability to capture the full range of reflectivities, especially when the range exceeds the detector's capabilities.
Innovation Solution
An imaging scanner system that uses a variable attenuator and optical assembly to generate multiple images of a specimen with different light attenuation levels, combining these images to create a single image with a dynamic range greater than the detector's limit, while excluding pixels outside the detector's range and averaging pixels within the range to enhance accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single image is captured with the detector, then the imaging speed is fast, but the dynamic range of detected reflectivities is limited
Solution Approach 1:
The patent divides the dynamic range measurement into multiple segments by capturing multiple images at different attenuation levels. Each image captures a portion of the reflectivity range, and these segments are combined to achieve the full dynamic range. This resolves the contradiction by allowing fast single-shot imaging while extending the measurable dynamic range through computational combination of multiple segmented measurements.
Solution Approach 2:
The patent introduces a new dimension of measurement by varying the attenuation level as an additional parameter. Instead of trying to capture all reflectivities in a single image, the system captures images at multiple attenuation levels (creating a new dimension) and then combines them. This dimensional approach allows the detector to operate within its dynamic range limits while the system as a whole achieves extended dynamic range.
2Measurement precision
If multiple images are captured with different attenuation levels to expand dynamic range, then the dynamic range of detected images is expanded, but the number of exposures required increases
Solution Approach 1:
The patent performs preliminary characterization of the sample to identify regions with extreme reflectivities before capturing the full image set. This preliminary action allows the system to determine which regions require multiple attenuation levels, thereby reducing the number of exposures needed for the full dynamic range capture. Not all regions need the same number of exposures, so this selective approach minimizes time loss.
Solution Approach 2:
The patent applies different numbers of attenuation levels to different regions of the sample based on their local reflectivity characteristics. High-reflectivity regions receive more attenuation levels than low-reflectivity regions. This local quality approach optimizes the balance between dynamic range expansion and time consumption, as each region is processed according to its specific requirements rather than uniformly.
3Loss of information
If pixels outside the detector dynamic range are included in the combined image, then the image completeness is maintained, but the measurement accuracy is reduced
Solution Approach 1:
The patent uses feedback from the combined image to identify and correct problematic pixels. After initial combination of images at different attenuation levels, the system analyzes the result to identify pixels that still fall outside the valid dynamic range. These feedback-identified pixels are then reprocessed or corrected, ensuring that only accurate measurements are included in the final image. This feedback loop maintains image completeness while preserving measurement accuracy.
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
The system effectively expands the dynamic range of detected images, allowing for accurate measurement of a wide range of reflectivities without the need for point-by-point adjustments, thereby improving imaging speed and reducing the number of exposures required, while maintaining image quality and minimizing noise.
Implementation Method 1
a variable attenuator adapted to receive a light beam generated by an MIR laser and that generates an attenuated light beam therefrom
Implementation Method 2
an optical assembly that focuses the attenuated light beam to a point on the specimen
Implementation Method 3
A light detector measures an intensity of light leaving the point on the specimen
Implementation Method 4
The first wire-grid polarization filter is characterized by a first linear polarization pass direction and a first actuator for causing the first linear polarization pass direction to rotate relative to the light beam
Data Source
AI summary
An imaging scanner and a method for using the same are disclosed. The scanner includes a variable attenuator adapted to receive a light beam generated by a MIR laser and that generates an attenuated light beam therefrom characterized by an attenuation level. The scanner includes an optical assembly that focuses the attenuated light beam to a point on a specimen. A light detector measures an intensity of light leaving the point on the specimen, the light detector being characterized by a detector dynamic range. A controller forms a plurality of MIR images from the intensity as a function of position on the specimen, each of the plurality of MIR images being formed with a different level of attenuation of the light beam. The controller combines the plurality of MIR images to generate a combined MIR image having a dynamic range greater than the detector dynamic range.