A sensitivity map deformation method for image quality improvement of Ultrasonic Tomography

Ultrasonic tomography (UT) technology is a typical industrial process tomography (IPT) technology, and is an effective method for the cross-section visualization of a gas-liquid two-phase flow pipeline. For typical non-iterative or iterative algorithms, the design of sensitivity maps is an important aspect for imaging results of UT. The construction of sensitivity maps is often based on the assumption of wave propagation theory, therefore, a sharp edge in a sensitive map (SESM) seems difficult to avoid, which produce low quality of reconstructed images when the sensing objects appear on the edge. This paper proposes the multi-level slope reduction methods to improve image quality via changing the effects of SESM. The multi-level slope reduction method is used to create a gradient slope and to eliminate the SESM effect. The Pearson correlation coefficient ( PCC ), position error ( PE ), and area error ( AE ) are selected as image quality evaluation criteria. The simulation and experimental results show that the proposed method can reduce the AE of the reconstruction results by approximately 0.1. The multi-level slope reduction method can increase the PCC s of the simulation and experimental reconstruction results by 0.02 and 0.06, respectively.