Multispectral Imaging With Continuously Graded Filter
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Solution Overview
Problem
Conventional multispectral sensors are limited by fixed narrow bandwidth filters, which restrict their performance and adaptability in capturing a wide range of electromagnetic spectrum information.
Innovation Solution
A multispectral imaging apparatus and method utilizing a continuously graded color filter with detectors configured in a pattern, allowing for variable spectral bandwidth and employing a time delayed integration method to enhance sensitivity by summing outputs from adjacent detector rows, thereby generating multiple spectrum response functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If fixed narrow bandwidth filters are used in conventional multispectral sensors, then the sensor configuration is compact, but the performance is limited and adaptability is reduced
Solution Approach 1:
The patent replaces fixed filters with a continuously variable optical filter that can dynamically adjust its spectral transmission characteristics. The filter's optical properties change continuously along its length, allowing real-time adjustment of spectral bandwidth and central wavelength without mechanical filter changes, thus achieving adaptability while maintaining compactness.
Solution Approach 2:
The invention changes the optical parameters (wavelength, bandwidth) of the filter continuously along its length rather than using discrete fixed filters. This allows the sensor to access multiple spectral bands by simply changing the position or orientation of the filter, providing versatile spectral coverage without adding complex filter assemblies.
2Loss of information
If fixed narrow bandwidth filters are used, then the sensor structure is simple, but the ability to capture information across a wide range of electromagnetic spectrum is limited
Solution Approach 1:
The continuously variable optical filter serves multiple spectral measurement functions within a single component. By adjusting the filter position or orientation, the same physical filter can provide different spectral passbands, making the sensor universally applicable to multiple spectral regions without requiring separate fixed filters for each band.
Solution Approach 2:
The patent adds a spatial dimension (continuous gradient along the filter length) to the spectral filtering function. Instead of using multiple discrete filters in one dimension, a single filter with continuous variation in the orthogonal dimension provides access to multiple spectral bands, capturing comprehensive spectral information without increasing filter count.
3Measurement precision
If detector outputs are summed using time delayed integration, then the sensitivity in specific wavelength bands is increased, but the processing complexity increases
Solution Approach 1:
The system performs preliminary temporal alignment of detector signals from different rows before summation. By pre-synchronizing the timing of signals based on their positional delays, the system prepares the data for optimal integration, ensuring that signals corresponding to the same spectral feature are aligned and can be coherently summed to enhance signal-to-noise ratio.
Solution Approach 2:
The time delayed integration method continuously processes detector outputs by maintaining a running sum of aligned signals over time. This continuous integration accumulates useful spectral information while averaging out random noise, providing sustained improvement in measurement precision without requiring discrete processing steps.
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 real-time adjustment of spectral bandwidth, improves signal-to-noise ratio, and allows for the generation of multiple spectrum response functions without changing filters, enhancing the adaptability and sensitivity of multispectral imaging systems.
Implementation Method 1
positioning a continuously graded color filter in front of a plurality of detectors, wherein wavelengths of energy passed by the filter vary smoothly as a function of location along the length of the filter, and wherein longitudinally adjacent points on the filter pass wavelengths of energy of overlapping bands
Implementation Method 2
a plurality of detectors located on a first side of the filter and configured in a pattern having a plurality of rows each having a plurality of detectors to output signals generated in response to an image moving across the length of the filter
Data Source
Figure 1A
Figure 1B~1C
Figure 2
AI summary
A method for multispectral imaging that includes positioning a continuously graded color filter in front of a plurality of detectors. Wavelengths of energy passed by the filter vary smoothly along the filter length and the detectors are configured in a pattern having a plurality of rows each having a plurality of detectors. Each of the plurality of rows is oriented across the length of the filter. The method also includes measuring outputs of the detectors in response to moving an image along the length of the filter and generating a spectrum response function for the image based on the outputs of two or more rows of the detectors using a time delayed integration method.