Bipolar Time-Over-Threshold Radiation Signal Processing for Linear Detection
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Solution Overview
Problem
Conventional time-over-threshold (TOT) methods for processing radiation signals in medical imaging devices suffer from nonlinearity in pulse amplitude to time width conversion, leading to complex and costly signal processing systems.
Innovation Solution
A method and apparatus that convert unipolar analog radiation signals into bipolar signals with distinct rise and fall times, using threshold comparisons to generate digital pulses, allowing for improved linearity and time resolution by calculating energy and time information from the widths and starting times of these pulses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional TOT method with unipolar signal and single threshold is used, then device complexity is reduced, but measurement precision deteriorates due to nonlinear relationship between pulse amplitude and TOT time width
Solution Approach 1:
The single threshold comparison is segmented into two threshold comparisons (first threshold and second threshold with opposite polarity). This segmentation allows the system to measure both the positive and negative excursions of the bipolar signal, creating a more linear relationship between pulse amplitude and TOT time width while maintaining relatively simple circuitry.
Solution Approach 2:
The patent inverts the conventional approach by converting the unipolar signal to a bipolar signal and using threshold values of opposite polarity. Instead of measuring only the positive excursion from a single threshold, the system measures both positive and negative excursions, which linearizes the amplitude-to-time-width conversion.
2Ease of manufacture
If unipolar signal processing is used, then ease of manufacture is improved, but measurement precision deteriorates due to limited time resolution
Solution Approach 1:
The patent converts the unipolar signal to a bipolar signal with opposite polarity thresholds, which enhances time resolution by capturing both rising and falling edges of the signal. This inversion approach maintains ease of manufacture while significantly improving measurement precision.
Solution Approach 2:
The patent changes the signal parameter from unipolar to bipolar and adjusts the threshold parameters to opposite polarities. This parameter change enables faster rise time detection and improved time resolution without complicating the manufacturing process.
3Measurement precision
If bipolar signal with dual threshold comparison is used, then measurement precision is improved through linearized amplitude-time conversion, but device complexity increases
Solution Approach 1:
The dual threshold comparison is segmented into two independent comparator operations: one for the positive threshold and one for the negative threshold. This segmentation simplifies the overall device complexity by breaking down the complex measurement task into two straightforward comparison operations.
Solution Approach 2:
The bipolar signal processing approach serves multiple functions simultaneously: it linearizes the amplitude-to-time-width conversion, improves time resolution, and provides both energy and time information measurement. This multi-functionality justifies the slight increase in device complexity by delivering comprehensive measurement capabilities.
Data Source
AI summary
A radiation apparatus and a radiation signal processing method are provided. To elaborate, the apparatus includes an input unit including a radiation detector; an amplification unit configured to amplify a signal input through the radiation detector; a bipolar signal generation unit configured to generate a bipolar signal by converting the amplified signal; and a comparison unit configured to output a digital signal on the basis of comparison results of the bipolar signal with a preset first threshold value and a preset second threshold value. Herein, the comparison unit includes a first comparator configured to output a digital pulse in an interval where the bipolar signal is larger than the first threshold value and a second comparator configured to output a digital pulse in an interval where the bipolar signal is smaller than the second threshold value.