DocumentCode :
432164
Title :
3D ultrasonic imaging and contour detection in sheet metal hydroforming
Author :
Keitmann-Curdes, O. ; Hensel, K. ; Knoll, P. ; Meier, H. ; Ermert, H.
Author_Institution :
Inst. of High Frequency Eng., Ruhr-Univ., Bochum, Germany
Volume :
1
fYear :
2004
fDate :
23-27 Aug. 2004
Firstpage :
697
Abstract :
The paper describes an ultrasonic imaging system with a low number of transducers in a sparse 2D array for contour detection of specularly reflecting sheet metals in a hydroforming process. Image reconstruction is performed with a SAFT (synthetic aperture focussing technique) algorithm as a first step. Within the SAFT image, the contour of the metal sheet can be detected in a second step. Experiments and results are presented for a linear 1D aperture with 2D and a 2D aperture with 3D imaging capabilities, respectively. Contour detection results in contours with an axial reconstruction error of less than 1 mm for complex shaped 2D objects. Simple 3D objects have been imaged as well. Besides this, a modified approach (angle weighted SAFT, AW-SAFT) is presented to work around the lack of SNR under special conditions caused by specular reflections. Gaps in the contours can be "filled up" and poorly imaged parts of the contours can be amplified with this approach, whereas noise is reduced.
Keywords :
feature extraction; forming processes; image reconstruction; ultrasonic imaging; 3D ultrasonic imaging; SNR; axial reconstruction error; contour detection; image reconstruction; sheet metal hydroforming; sparse 2D array; specular reflection; synthetic aperture focussing technique; Acoustic reflection; Apertures; Focusing; Image reconstruction; Noise reduction; Object detection; Signal to noise ratio; Ultrasonic imaging; Ultrasonic transducer arrays; Ultrasonic transducers;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Ultrasonics Symposium, 2004 IEEE
ISSN :
1051-0117
Print_ISBN :
0-7803-8412-1
Type :
conf
DOI :
10.1109/ULTSYM.2004.1417817
Filename :
1417817
Link To Document :
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