Fluorescence Imaging System Using Digital FIR Filters for Phase Alignment
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Solution Overview
Problem
Endoscopes face limitations in fluorescence imaging due to low quantum efficiency of image sensors, leading to reduced sensitivity and contrast in captured images, particularly when using infrared light for fluorescent dye imaging.
Innovation Solution
An enhanced fluorescence imaging system that includes a light source emitting infrared and white light, paired with image sensors and data processing hardware that employs digital finite impulse response filters to enhance image data, aligning and adjusting sensitivity and contrast to improve image quality, and correct for misregistration and diffusion-based contrast loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If image sensors with higher quantum efficiencies are used, then sensitivity and contrast are improved, but phase misalignment and contrast loss occur
Solution Approach 1:
The imaging system uses separate image sensors for white light and infrared light, processing each channel independently through dedicated image processing circuits that handle alignment and contrast enhancement separately, avoiding the phase misalignment issues that occur when using a single sensor for both wavelengths
Solution Approach 2:
The patent introduces an intermediary image processing circuit that receives both white light and infrared image data, performs spatial alignment and contrast enhancement as intermediate processing steps, and then combines the processed channels to produce the final enhanced fluorescence image
2Measurement precision
If digital FIR filters are applied to enhance infrared image data, then sensitivity and contrast are improved, but processing complexity increases
Solution Approach 1:
The system creates a processed copy of the infrared image data by applying digital FIR filters to enhance contrast and sensitivity, while the original unprocessed data is retained for reference, allowing the enhanced version to be displayed without permanently altering the acquisition system
Solution Approach 2:
The patent applies parameter changes through digital FIR filters that modify the frequency response and amplitude characteristics of the infrared image signal, adjusting contrast and sensitivity by changing signal parameters rather than altering the physical imaging hardware
3Productivity
If white light and infrared light are captured simultaneously, then imaging speed is improved, but color filter array modulation causes contrast loss
Solution Approach 1:
The imaging system segments the spectral information by using separate dedicated sensors for white light and infrared light, eliminating the color filter array modulation artifacts that occur when a single sensor must handle both wavelengths, while maintaining simultaneous capture capability
Solution Approach 2:
The patent extracts the infrared signal component from the combined light path by using a separate infrared-sensitive sensor, isolating it from the white light channel to prevent color filter array modulation from degrading the contrast accuracy of the fluorescence 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
The system significantly improves the sensitivity and contrast of infrared image data, effectively reconstructing fluorescent dye images with minimal color filter array modulation and maximally flat spatial frequency response, enhancing diagnostic capabilities in medical procedures.
Implementation Method 1
the infrared light is used to irradiate medication (e.g., dye) administered to a patient with infrared light, which in turn causes the medication to emit fluorescence light
Implementation Method 2
filtering the infrared image data with fluorescence image enhancer having a first digital finite impulse response (FIR) filter configured to produce a magnitude response of zero at a horizontal Nyquist frequency and a vertical Nyquist frequency
Implementation Method 3
The second digital FIR filter is configured with a phase response to spatially align the white light image data with the infrared image data
Data Source
AI summary
A fluorescence imaging system is configured to generate a video image onto a display. The system includes a light source for emitting infrared light and white light, an infrared image sensor for capturing infrared image data, and a white light image sensor for capturing white light image data. Data processing hardware performs operations that include filtering the infrared image data with a first digital finite impulse response (FIR) filter configured to produce a magnitude response of zero at a horizontal Nyquist frequency and a vertical Nyquist frequency. The operations also include filtering the infrared image data with a second digital FIR filter configured with a phase response to spatially align the white light image data with the infrared image data. The operations also include combining the white light image data and the infrared image data into combined image data and transmitting the combined image data to the display.