Thesis
Generation of high resolution tomographic images for NDT applications
可下载的内容
下载PDF文件- Creator
- Rights statement
- Awarding institution
- University of Strathclyde
- Date of award
- 2001
- Thesis identifier
- T10352
- Qualification Level
- Qualification Name
- Department, School or Faculty
- Abstract
- Techniques for the generation of quantitative ultrasonic images in non-destructive testing have generally involved a substantial cost in terms of data storage and computational time, and have thus found limited application. Preference has therefore been given to the more straightforward imaging methods, such as main beam projection, which detect the presence of defects and provide a limited flaw sizing capability. The relatively small number of flaws requiring detailed examination, coupled with substantial increases in available data storage and computational power, have made it possible to use a number of straightforward tomographic reconstruction methods to produce high resolution images of flaws contained within the material under examination. A set of these images are then fused together using a novel fuzzy logic image fusion technique into a single image from which more accurate measurements of flaw size, shape and orientation can be made. However, if the quality of the raw A-scan data is not sufficiently high then the data will be filtered using Maximum Likelihood Deconvolution (MLD). The aim of this blind deconvolution method is to improve the time resolution and Signal to Noise Ratio of the A-scan data with only knowledge obtained from the data, this is in contrast to the majority of techniques currently used for this purpose. The three tomographic methods which have been implemented in this work are Reflection tomography, Time-of-flight Diffraction tomography and Transmission tomography. In addition a Single Bounce Image Enhancement method has been developed to improve the images. Selection of images used in the fusion process depends on the nature of the flaw, as each of these methods identifies different characteristics of the flaw shape. The components of the imaging system have been validated experimentally by the generation of high resolution images from a variety of flaws contained within cylindrical aluminium test specimens.
- Resource Type
- DOI
- EThOS ID
- uk.bl.ethos.366762
- Date Created
- 2001
- Former identifier
- 620223
关系
项目
缩略图 | 标题 | 上传日期 | 公开度 | 行动 |
---|---|---|---|---|
PDF of thesis T10352 | 2021-07-02 | 公开 | 下载 |