A count rate-dependent method for spectral distortion correction in photon counting CT

2018 ◽  
Author(s):  
Jannis Dickmann ◽  
Joscha Maier ◽  
Stefan Sawall ◽  
Marc Kachelriess ◽  
Christian Broennimann ◽  
...  
Keyword(s):  
Count Rate ◽  
Photon Counting ◽  
Distortion Correction ◽  
Spectral Distortion ◽  
Rate Dependent

scholarly journals A neural network-based method for spectral distortion correction in photon counting x-ray CT

2016 ◽  
Vol 61 (16) ◽  
pp. 6132-6153 ◽  
Author(s):  
Mengheng Touch ◽  
Darin P Clark ◽  
William Barber ◽  
Cristian T Badea
Keyword(s):  
Neural Network ◽  
Photon Counting ◽  
Distortion Correction ◽  
Spectral Distortion ◽  
X Ray

scholarly journals Image-based spectral distortion correction for photon-counting x-ray detectors

2012 ◽  
Vol 39 (4) ◽  
pp. 1864-1876 ◽  
Author(s):  
Huanjun Ding ◽  
Sabee Molloi
Keyword(s):  
Photon Counting ◽  
Distortion Correction ◽  
Spectral Distortion ◽  
X Ray

scholarly journals Design of a Real-Time Breakdown Voltage and On-Chip Temperature Monitoring System for Single Photon Avalanche Diodes

Electronics ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 25
Author(s):  
Shijie Deng ◽  
Alan P. Morrison ◽  
Yong Guo ◽  
Chuanxin Teng ◽  
Ming Chen ◽  
...  
Keyword(s):  
Real Time ◽  
Breakdown Voltage ◽  
Count Rate ◽  
Single Photon ◽  
Photon Counting ◽  
Temperature Monitoring ◽  
Dark Count ◽  
Chip Temperature ◽  
Avalanche Diodes ◽  
On Chip

The design and implementation of a real-time breakdown voltage and on-chip temperature monitoring system for single photon avalanche diodes (SPADs) is described in this work. In the system, an on-chip shaded (active area of the detector covered by a metal layer) SPAD is used to provide a dark count rate for the breakdown voltage and temperature calculation. A bias circuit was designed to provide a bias voltage scanning for the shaded SPAD. A microcontroller records the pulses from the anode of the shaded SPAD and calculates its real-time dark count rate. An algorithm was developed for the microcontroller to calculate the SPAD’s breakdown voltage and the on-chip temperature in real time. Experimental results show that the system is capable of measuring the SPAD’s breakdown voltage with a mismatch of less than 1.2%. Results also show that the system can provide real-time on-chip temperature monitoring for the range of −10 to 50 °C with errors of less than 1.7 °C. The system proposed can be used for the real-time SPAD’s breakdown voltage and temperature estimation for dual-SPADs or SPAD arrays chip where identical detectors are fabricated on the same chip and one or more dummy SPADs are shaded. With the breakdown voltage and the on-chip temperature monitoring, intelligent control logic can be developed to optimize the performance of the SPAD-based photon counting system by adjusting the parameters such as excess bias voltage and dead-time. This is particularly useful for SPAD photon counting systems used in complex working environments such as the applications in 3D LIDAR imaging for geodesy, geology, geomorphology, forestry, atmospheric physics and autonomous vehicles.

scholarly journals High Dynamic Range Imaging with TDC-Based CMOS SPAD Arrays

Instruments ◽  
2019 ◽  
Vol 3 (3) ◽  
pp. 38 ◽  
Author(s):  
Majid Zarghami ◽  
Leonardo Gasparini ◽  
Matteo Perenzoni ◽  
Lucio Pancheri
Keyword(s):  
Dynamic Range ◽  
Single Photon ◽  
Photon Counting ◽  
Complementary Metal Oxide Semiconductor ◽  
High Dynamic Range ◽  
Oxide Semiconductor ◽  
Photon Flux ◽  
Integration Time ◽  
Rate Dependent ◽  
High Dynamic

This paper investigates the use of image sensors based on complementary metal–oxide–semiconductor (CMOS) single-photon avalanche diodes (SPADs) in high dynamic range (HDR) imaging by combining photon counts and timestamps. The proposed method is validated experimentally with an SPAD detector based on a per-pixel time-to-digital converter (TDC) architecture. The detector, featuring 32 × 32 pixels with 44.64-µm pitch, 19.48% fill factor, and time-resolving capability of ~295-ps, was fabricated in a 150-nm CMOS standard technology. At high photon flux densities, the pixel output is saturated when operating in photon-counting mode, thus limiting the DR of this imager. This limitation can be overcome by exploiting the distribution of photon arrival times in each pixel, which shows an exponential behavior with a decay rate dependent on the photon flux level. By fitting the histogram curve with the exponential decay function, the extracted time constant is used to estimate the photon count. This approach achieves 138.7-dB dynamic range within 30-ms of integration time, and can be further extended by using a timestamping mechanism with a higher resolution.

Impact of photon counting detector spectral distortion on virtual non-contrast CT imaging

2020 ◽  
Author(s):  
Mang Feng ◽  
Xu Ji ◽  
Ran Zhang ◽  
Jessica R. Miller ◽  
Guang-Hong Chen ◽  
...  
Keyword(s):  
Photon Counting ◽  
Ct Imaging ◽  
Spectral Distortion ◽  
Photon Counting Detector ◽  
Contrast Ct
Sign in / Sign up

Export Citation Format

Share Document