Split Signal Corrector for Direct Conversion Detector Arrays
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Solution Overview
Problem
Direct conversion photon counting detectors face spectral degradation due to signal splitting between pixels, particularly as pixel size decreases, leading to compromised performance and accuracy in image reconstruction.
Innovation Solution
A digital signal processing approach is implemented to identify and correct split signals by combining the values of neighboring pixels with coincident detections, using a split signal corrector that sums the values of pixels with the largest magnitude and sets the other pixel values to zero, thereby reconstructing the full charge signal and reducing noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pixel size is decreased to reduce pixel count rate and pulse pile-up, then performance is improved, but signal splitting between pixels increases causing spectral degradation
Solution Approach 1:
The patent combines signals from multiple detector pixels that detect coincident photons. By merging the charge signals from pixels that share a photon detection event, the system reconstructs the full energy signal that would have been captured by a single larger pixel, thereby preventing spectral degradation while maintaining the benefits of smaller pixel sizes for reduced count rate and pulse pile-up.
2Measurement precision
If all neighboring signals are combined above a trigger threshold to improve spectrum, then spectral accuracy is improved, but variable losses occur and noise increases
Solution Approach 1:
The system uses feedback through coincidence detection to identify which neighboring pixel signals should be combined. By detecting coincident photon events and using this information to selectively combine only the relevant signals, the system avoids combining noise from non-coincident signals while still recovering the full energy signal, thereby preventing both signal loss and noise increase.
3Measurement precision
If all neighboring signals are combined without thresholding to recover signal, then signal recovery is improved, but noise from increased number of pixels increases
Solution Approach 1:
The coincidence detection mechanism provides feedback that identifies which signals should be combined. Only signals from pixels that detect coincident photons are combined, which ensures that the full energy signal is recovered without adding noise from unrelated pixels. This selective combining based on coincidence feedback prevents noise increase while maintaining signal recovery.
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
This method effectively mitigates signal losses and improves spectral accuracy by reconstructing the full energy signal, enhancing image quality and reducing noise, particularly in computed tomography and other modalities using direct conversion detectors.
Implementation Method 1
direct conversion detectors, which include a direct conversion material such as CdTe or Cd(Zn)Te with detector pixels attached thereto. With direct conversion, incident radiation is converted directly to a charge signal indicative of the energy of the radiation
Data Source
AI summary
A system (100) includes a photon counting detector array (116) including a direct conversion material (118) and a plurality of detector pixels (120) affixed thereto, and a split signal corrector (126) that corrects the output of the plurality of detector pixels for split signals. A method includes receiving an output signal of each of a plurality of detector pixels affixed to a direction conversion material of photon counting detector array, and correcting the output of the plurality of detector pixels for split signals. A computer readable storage medium encoded with computer readable instructions, which, when executed by a processer, cause the processor to: receive an output signal of each of a plurality of detector pixels affixed to a direction conversion material of photon counting detector array, and correct the output of the plurality of detector pixels for split signals.