Improved image reconstruction based on ultrasonic transmitted wave computerized tomography on concrete

Abstract

Considering the non-uniqueness and instability of concrete defect detection in construction engineering, ultrasonic time of flight data and maximum likelihood expectation maximization algorithm were proposed to improve the readability of the ultrasonic reconstruction image. Ultrasonic transmitted waves reflect internal information when through concrete structures. Measurement signals were regularized and processed as transit time parameters. Maximum likelihood expectation maximization algorithm was optimized for image reconstruction of the concrete structure. The interpolation data as the density of measurement data was used to improve the readability of reconstruction images. The experimental measurement system, improved image reconstruction algorithm, and interpolation method were verified in detail by using simulation and concrete phantoms. The proposed image reconstruction technique based on maximum likelihood expectation maximization overcame the disadvantages of the traditional image reconstruction method, and it was effective to improve the accuracy and the quality of image reconstruction on concrete. Time of flight data and normalized interpolation were discussed in detail during image reconstruction. The results showed that it could make the position of an abnormal object more obvious, and it was more accurate for reflecting the internal structure of concrete.

nfluence of Measuring Points in Ultrasonic Tests on the Tomographic Image Quality of Concrete

“…Regarding the identification of non-homogeneity in concrete, [SCH14] used ultrasonic tomography to determine the location and size of internal flaws in a sample of concrete and confirmed the reliability of the technique. In the experiment proposed by [FAN18], the images of concrete specimens were reconstructed by using transit time parameters interpolation and MLEM improved algorithm. The proposed image reconstruction technique was effective to improve the accuracy and the quality of image reconstruction on concrete.…”

“…By means of the interpolation technique it is possible to reconstruct or approximate the continuous signals from a series of discrete points [CHE19]. This technique has been widely applied to super-resolution and im-1 age reconstruction in ultrasonic tomography [DON16] [FAN17] [FAN18].…”

Ultrasonic computed tomography-based internal-defect detection and location of underwater concrete piers

“…By evaluating the parameters of the wave's travel time and velocity field, it is possible to discover defects [24,25]. Currently, several researchers are utilizing the ultrasonic tomography to detect the location and size of internal defects in concrete, such as cracks, delamination, mudballs, and reinforcing steels [26][27][28]. Additionally, researchers also improved the ultrasonic inversion algorithm.…”