Digital Deconvolution Filter for Photon Counting Linearity
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Solution Overview
Problem
Existing photon counting methods face limitations in linear dynamic range due to nonlinearities at high photon count rates, requiring trade-offs between detector types and suffering from sensitivity mismatches and noise contributions, which compromise accurate quantitation and dynamic range extension.
Innovation Solution
A quantitative optical microscopy arrangement using a digital deconvolution filter with coefficients based on linear discriminant analysis to extend the linear range of photon counting, allowing for accurate determination of the mean Poisson distribution and maintaining signal-to-noise ratio across a wide range of photon fluxes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If photon counting is used to detect low intensity light, then sensitivity is improved, but nonlinearities occur at high photon count rates
Solution Approach 1:
The patent segments the detection process by using multiple detectors with different neutral density filter configurations. Each detector is optimized for a specific photon flux range, allowing the system to maintain linearity across a broad dynamic range by selecting or combining results from appropriate detector segments.
Solution Approach 2:
The patent changes the optical parameters of the detection system by using multiple detectors with different neutral density filter densities. This allows each detector to operate in its linear range for different photon flux levels, effectively extending the overall linear dynamic range while maintaining sensitivity.
2Quantity of substance
If multiple photo detectors and fiber-optic beam splitters are used to extend linear dynamic range, then measurement range is improved, but device complexity increases
Solution Approach 1:
The patent creates a universal detection system where multiple detectors with different neutral density configurations work together as an integrated unit. The system can handle a wide range of photon fluxes using the same detector array, with software algorithms selecting appropriate detectors based on signal levels, thereby extending dynamic range without proportionally increasing complexity.
3Quantity of substance
If multiple detectors are combined to extend linear range, then measurement capability is improved, but noise contribution increases
Solution Approach 1:
The patent extracts and removes noise contributions by using detectors with different neutral density filter configurations. By selecting detectors operating in their optimal linear range for specific signal levels and using algorithms to combine results, the system minimizes noise accumulation while extending dynamic range.
4Adaptability or versatility
If sensitivity mismatch occurs in instrument responses from single photon counting with ADC, then detection flexibility is improved, but quantitation accuracy worsens
Solution Approach 1:
The patent addresses sensitivity mismatch by using detectors with different neutral density filter densities, effectively changing the optical parameters to match different photon flux levels. This allows each detector to operate with optimized sensitivity for its intended range, maintaining quantitation accuracy across the full dynamic range while preserving detection flexibility.
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 solution effectively extends the linear range of photon counting to approximately 74 simultaneous photons, maintaining signal-to-noise ratios close to the theoretical limit and enabling continuous quantitation across a broad dynamic range, from low-light to high-light conditions.
Implementation Method 1
a detector configured to receive light reflected from or emitted through the sample. The detector has an optical-voltaic converter configured to convert the received light into a representative voltage
Data Source
AI summary
A quantitative optical microscopy arrangement is described. Specifically, a digital filter derived from linear discriminant analysis is described for recovering impulse responses in applications that may include photon counting from a high speed photodetector and applied to remove ringing distortions from impedance mismatch in multiphoton fluorescence microscopy. Training of the digital filter is achieved by defining temporally coincident and non-coincident transients and identifying the projection within filter-space that best separates the two classes. The training allows rapid data analysis by digital filtering. The LDA filter is also capable of recovering deconvolved impulses for single photon counting from highly distorted ringing waveforms from an impedance mismatched photomultiplier tube. The LDA filter is also successful in removing these ringing distortions from two-photon excited fluorescence micrographs and may extend the dynamic range of photon counting by about three orders of magnitude through minimization of detector paralysis.