A dual-mode industrial CT

A modified conjugate gradient method based on the Tikhonov system for computerized tomography (CT)

“…(3) into an optimization problem min J(x) = ‖Cx − p‖ 2 + λ‖Lx‖ 2 (5) where λ is a positive number, which is called the regularization parameter, L is the matrix corresponding to a certain linear operator, which always represents the first or second derivative operator, as shown in Eq. (6)…”

“…Because of the characteristics of non-invasiveness and visibility, CT is used in the industrial area for non-destructive testing (NDT) inspections, measurements and metrology, etc. [1]. Compared with other tomography techniques, e.g.…”

“…The degree of attenuation is dependent on the material composition and the size of the object [5]. Using the principle of radiation attenuation, measurements along different directions through the investigated object can reconstruct internal cross-sectional information of the scanned object.…”

<title>Laser-Compton photon radiography for nondestructive test of bulk materials</title>

“…Using the high-energy photons, nondestructive test of metals surrounded by concrete, for example, can be possible. Compared to the conventional gamma-ray radiography and CT systems using a radioactive isotopes, such as 241Am, 137Cs, and '°Co [2,3], the present method is suitable to scan bulk materials with reduced time and dose.…”

High-energy photon radiography system using laser-Compton scattering for inspection of bulk materials

“…8,9 One of them is a long penetrating distance of the high-energy photons, which is useful for scanning materials of high atomic numbers surrounded or hidden by materials of low atomic numbers, because the materials of low atomic numbers can be transparent for the high-energy photons. Photons with energies higher than about a few MeV are suitable for the inspection of the materials with high atomic numbers, such as iron and lead, because the total attenuation coefficient 10 is minimum around these energies.…”