金属圆棒超声螺旋扫查检测的合成孔径成像技术

李振杰, 蔡桂喜, 张博, 李经明, 李建奎

Synthetic Aperture Imaging Technology for Ultrasonic Spiral Scanning Detection of Metal Bars

LI Zhenjie, CAI Guixi, ZHANG Bo, LI Jingming, LI Jiankui

图2 圆棒在极坐标系下SAFT (pSAFT)成像原理图

Fig.2 Schematics of SAFT in polar coordinate system (pSAFT) imaging of round bar (R—cross section radius of round bar, r—radius of inscribed circle of sound beam, θ—twice the incident angle of sound beam, θ'—aperture angle of virtual source, φ1…φi…φn—circumferential scanning angle, γ and γ'—synthetic aperture radian for virtual inspection aperture near and far away object A respectively, ρ and α—location for defect in polar system by polar radius and angle respectively, d—distance from virtual aperture position to object point) (a) surrounding-scan-mode, object B in the ‘r’ zone (b) scope of virtual inspection aperture for object A (scanning at d<R side) (c) scope of virtual inspection aperture for object A (scanning at d>R side) (d) object B signal set corresponding to each scanning angle (e) object A signal set corresponding to each scanning angle (f) circular section tomograph