Effects of surface mapping corrections with synthetic-aperture focusing techniques on ultrasonic imaging
Image processing to improve the resolution of ultrasonic imaging systems requires an accurate knowledge of the geometry and properties of the media through which the ultrasound travels. This is particularly true when a method such as the Synthetic Aperture Focusing Technique (SAFT) is used. For SAFT to function properly, it is necessary to accurately know the path traveled by the ultrasound from transducer to target and back again. A form of SAFT imaging is described in which the image routine also constructs a map of the target surface. This map is then used to accurately calculate the propagation history of the ultrasound for the SAFT processing. The resolution and positional accuracy of unprocessed images, unmapped SAFT images, and surface mapping SAFT images are compared. All but the surface mapping images show significant errors in positional accuracy for relatively small surface deviations. The surface mapping correction however, brings the imaging accuracy back to within the limits of the mechanical experimental error. In addition, results achieved with a flat ultrasonic transducer suggest significant simplifications that may ease field implementation of SAFT systems.
- Research Organization:
- EG and G Idaho, Inc., Idaho Falls (USA)
- DOE Contract Number:
- AC07-76ID01570
- OSTI ID:
- 5481316
- Report Number(s):
- EGG-M-06981; CONF-810839-8; ON: DE82006270
- Resource Relation:
- Conference: AF/DARPA review of progress in quantitative NDE, Boulder, CO, USA, 2 Aug 1981
- Country of Publication:
- United States
- Language:
- English
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