P. Leggat

The Application of Case‐Based Reasoning to Ultrasonic Data for Use in Inspection Qualification

This paper describes the application of case‐based reasoning (CBR) to provide decision support for the NDT engineer during Inspection Qualification. A key element of this process is to present experimental evidence on the effectiveness of the inspection. A prototype for the system has been developed using a case‐base which describes the defect, the probe and response. This paper discusses the motivation for the system, the case structure, weightings, similarity measures, retrieval techniques and its design and implementation.

A software system for inspection qualification

In safety critical and non‐routine situations, inspection capability may need to be demonstrated by an independent process of Inspection Qualification (IQ). This process is costly and time consuming. Therefore an approach that could aid in its production would be beneficial. This paper describes the development of interactive software tools empowering the NDT engineer to design and evaluate the capability of an ultrasonic inspection within a single environment. This paper discusses the motivation for the system, the design and implementation of the tools and the benefits it will provide.

Automated Error Interpretation in Flaw Response Models for Ultrasonic NDT

Theoretical modelling programs are used to validate test procedures during Inspection Qualification and to aid interpretation of results. “Flags” occur when the models run outside their range of validity and warn the user of possible inaccuracies in predictions. However, in order to interpret these flags significant expertise in the theoretical background to the models is required by the user. This paper describes why these flags occur and the automated steps that can be taken to extract useful predictions when they do, thus simplifying the modelling procedure.

Interactive software tools for inspection qualification

The demonstration of ultrasonic inspection reliability through Inspection Qualification is important for non‐routine or safety critical tests. However, since Inspection Qualification is time consuming and costly, the provision of interactive software tools to aid the process offers substantial advantages. This paper describes such an interactive tool set to aid Inspection Qualification. Operating within a 3D CAD environment it consists of ray tracing, coverage map and defect/ray interaction tools. Initial ray amplitudes are also calculated and displayed, and estimation of favorable surface scanning positions determined.

3D ultrasonic ray tracing in AutoCAD

To assist with the design and validation of testing procedures for NDT, add-on modules have been developed for AutoCAD® 2000. One of the modules computes and displays ultrasonic 3D ray tracing. Another determines paths between two points, for instance a probe and a target or two probes. The third module displays phased array operational modes and calculates element delays for phased array operation. The modules can be applied to simple or complex solid model components.

Segmentation and classification of images reconstructed from reduced A-scan data sets

This paper will describe the modification and evaluation of a number of segmentation algorithms to identify suspect regions within images reconstructed from Micropulse (MIPS) reduced data sets, used extensively in the UK Nuclear Industry. In addition, the paper will detail the alterations required to an existing flaw sentencing expert system for a selection of components and defect types. Experimental data will be used throughout. The expert system has been implemented using CLIPS (‘C’ Language Integrated Production System), with the NDT interpreters decision making process represented by a set of production rules of the form: IF A THEN B. Within the expert system, uncertainty is represented and propagated using fuzzy sets theory. A core set of rules constitutes the base expert system. A user can produce a tailored, local KSB (specific to a particular component and/or defect) through the addition of new rules and/or the modification of the existing rule set. The framework for addition of new rules is in t...

Ultrasonic NDT data reconstruction, visualization and analysis in AutoCAD 2000

This paper describes an implementation of 3D ultrasound data reconstruction, display and analysis within AutoCAD®2000. In addition, a number of standard weld templates, scalable via dialog boxes, have been implemented. Currently, MIPS (Micropulse) formatted data can be imported, reconstructed and displayed. A series of dialog boxes allows specification of the scanning configuration. The reconstruction algorithm takes full account of reflection and mode conversion at the component surfaces. The resultant ultrasound image is presented in ‘3D,’ with tools for image manipulation and interrogation.

Automated Interpretation for Ultrasonic NDT Data

Classification and sizing of suspect indications within ultrasonic data can be a complex, time consuming task. An expert system [1], modelled on NDT interpreters’ knowledge and method of inference, has been designed to perform automated classification and sizing of indications extracted from 3D ultrasonic images. Consequently, a range of segmentation algorithms has been evaluated to isolate suspect indications. The techniques currently under investigation include histogram thresholding, co-occurrence matrix analysis and morphological techniques. The expert system, written in CLIPS (‘C’ Language Integrated Production System), can be modified by the system operator using a Windows based dialog editing facility to add new rules and edit existing rules. The system can therefore be tailored to a particular inspection situation.