Photon Detector Baseline Shift Correction via Pulse Threshold Monitoring
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Solution Overview
Problem
Photon counting detector performance is degraded at high X-ray flux due to uncontrollable baseline shifts in the analogue signal, caused by changes in sensor material resistivity and electric fields, leading to compromised image quality and inaccurate photon counting.
Innovation Solution
A processing unit that continuously monitors and corrects baseline shifts by determining changes in the rate of exceeding pulse height thresholds, specifically set at the edges of a noise peak in the pulse height spectrum, allowing for precise baseline shift measurement and correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If photon counting detector operates at high X-ray flux, then detection capability is improved, but baseline shift occurs causing performance degradation
Solution Approach 1:
The patent implements a feedback mechanism where the processing unit continuously monitors the baseline of the analogue signal and determines baseline shifts by analyzing changes in the rate of exceeding pulse height thresholds. This real-time monitoring and correction feedback loop compensates for baseline drift caused by high flux operation, allowing the detector to maintain performance at high X-ray flux levels while correcting baseline instability.
2Measurement precision
If baseline shift occurs in analogue signal, then measurement accuracy deteriorates, but continuous monitoring enables real-time correction
Solution Approach 1:
The patent applies preliminary action by continuously determining the baseline shift before it significantly degrades measurement accuracy. The processing unit monitors the rate of exceeding pulse height thresholds in real-time and corrects the baseline shift proactively, preventing substantial deterioration of photon counting accuracy rather than reacting after damage occurs.
3Measurement precision
If pulse height threshold is set at edge of noise peak, then baseline shift sensitivity is improved, but threshold selection complexity increases
Solution Approach 1:
The patent utilizes parameter changes by setting the pulse height threshold at a specific characteristic point of the noise peak (the edge). This specific parameter selection optimizes the sensitivity of baseline shift detection, as changes in baseline cause rapid changes in the rate of exceeding this threshold. The processing unit analyzes the pulse height spectrum to identify the noise peak edge and sets the threshold accordingly, achieving high detection sensitivity through optimized parameter selection.
Data Source
AI summary
The present invention relates to determining baseline shift of an electrical signal generated by a photon detector (102) of an X-ray examination device (101). For this purpose, the photon detector comprises a processing unit (103) that is configured to determine a first crossing frequency of a first pulse height threshold by the electrical signal generated by the photon detector. The first pulse height threshold is located at a first edge of a noise peak in the pulse height spectrum of the electrical signal.