Infrared species limited data tomography through Tikhonov reconstruction

Laser absorption spectroscopy for combustion diagnosis in reactive flows: A review

“…Many reconstruction techniques incorporate a prior information (sample-based or temporal prior information) through the Bayesian formulation (137,156,157). In general, a prior information such as smoothness of the subject and non-negativity constraint can be combined with the incomplete data to improve the image quality (158). The smoothing process provides the regularization necessary to render the inherently ill-posed problem tractable, while the non-negativity constraint maintains physically meaningful parameters.…”

“…The smoothing process provides the regularization necessary to render the inherently ill-posed problem tractable, while the non-negativity constraint maintains physically meaningful parameters. The first-order Tikhonov regularization spans the null space of A with a smoothing matrix L, which approximates the directional derivatives (155,158). For a Cartesian grid, L is defined as…”

978-1-60595-465-3 Research on Nondestructive Testing Based Back Projection Method in the Bearing Inspection

“…[4,5] Because the wave is propagated along the boundary-limited structure, it is a specific type of wave that is reflected and interfered by the interface during the forward propagation of the longitudinal and transverse waves, and its velocity and propagation form are different from those of the structural thickness and frequency are closely related [6] . According to the research of related literature, only a few scholars have used experimental and finite element simulation methods to study the propagation of guided wave propagation in inhomogeneous material.…”

“…In 1996, Chen introduced the time domain analysis method into the ultrasonic testing, which greatly solved the problem of weak defect signal analysis. [4,7] After continuous development, short-time Fourier transform, Cohen class time-frequency distribution, Wigner-Ville time-frequency distribution, wavelet transform, empirical mode decomposition and Hilbert-Huang transform are widely used in the current real-time detection.…”

“…[4,9] For example, Japanese BVV company developed the wheel of the ultrasonic detection system for the bearing surface defects detection, which can achieve rapid automated detection and switch A / B / C three scanning mode, but there is a certain detection blind spot. [2,6] Nishny in Russia company developed the ultrasonic testing system, with two liquid immersion to achieve automated testing, high reliability, can achieve the bearing and the surface of the small defects detection, but the shortcomings of the existence of detection blind spots.…”