An optimised method for material identification using a photon counting detector

System-independent material classification through X-ray attenuation decomposition from spectral X-ray CT

“…The functions 1∕ 3 Figure 1: Illustration of the dual-energy CT, SRZE and SIMCAD methods. Left: in dual-energy X-ray CT, the sample attenuation is measured at low-and high energies with two different spectra that are overlapping and thus reduces the estimation performance [24,25]. Center: in classical spectral X-ray CT, the sample attenuation is measured at multiple energy bins using PCDs [23,28].…”

“…In material identification by radiography, Rinkel et al [24] presented through experimental data that the false detection rate when using 90 energy bins with a PCD was reduced by a factor of up to 2 and more than 3 (for thin objects) compared to an optimised dual-energy bins approach applied both on the same PCD data and to a dual-layer sandwich detector, re-spectively. Beldjoudi et al [20,25] showed through simulations in Radiography that PCDs with data condensed into two energy bins enhanced recognition of single materials by over 50% relative to dual-layer sandwich detectors. Increasing the number of energy bins resulted in a further rise of 80% in material identification with 90 energy bins compared to dual-layer sandwich detectors.…”

Non-invasive material discrimination using spectral x-ray radiography

“…21 Radiographic noise was assumed to be dominated by counting statistics and to follow a Poisson distribution. 26 Noise was added independently to the simulated data in each energy bin of each pixel using the Matlab function poissrnd.…”

“…This selection of bin thresholds is based on previous analyses. 26,27 RESULTS AND DISCUSSION Figure 2 shows simulated transmission data, d, recorded by the spectral detector for the object in Figure 1, summed over all energy bins. The slight profile of the plutonium wedge can be seen in the middle of the image.…”

“…17 For additional information, see the supplementary material. 29 A spectral shift has been used to measure the thickness of single-layer materials for security applications, 26 in medical imaging to improve contrast, 13 and to distinguish between different types of tissue with the use of contrast agents in computed tomography inspections. 18 In principle though, this information can also be used to determine the presence and quantity of specific materials in a composite object using single-view radiography.…”