Location

La Jolla, CA

Start Date

1-1-1993 12:00 PM

Description

Current 3-D X-ray CT imaging technology is limited in some cases by the size and sensitivity of the X-ray detector. This limitation can be overcome to some degree by the use of region-of-interest (ROI) reconstruction software when only part of a larger object need be examined. However, images produced from ROI data often exhibit severe density shading if they are reconstructed by unaltered 3-D X-ray CT algorithms (called Global methods here). These density artifacts can be so severe that low-contrast features are hidden. Time-consuming methods introduced previously to remedy these artifacts require specialized processing to replace or approximate the missing data outside the desired volume. Although these methods are required for true densitometry measurements, in many NDT applications only the detection of internal features or relative density variations is required. In such cases, the use of Local (or Lamda) X-ray CT, which produces an “edge-enhanced” reconstruction and requires only minor modifications of the standard 3-D X-ray CT algorithm, is recommended.

Book Title

Review of Progress in Quantitative Nondestructive Evaluation

Volume

12A

Chapter

Chapter 1: Development of Standard Techniques

Section

Radiography and CT

Pages

357-364

DOI

10.1007/978-1-4615-2848-7_46

Language

en

File Format

application/pdf

Share

COinS
 
Jan 1st, 12:00 PM

Development and application of local 3-D CT reconstruction software for imaging critical regions in large ceramic turbine rotors

La Jolla, CA

Current 3-D X-ray CT imaging technology is limited in some cases by the size and sensitivity of the X-ray detector. This limitation can be overcome to some degree by the use of region-of-interest (ROI) reconstruction software when only part of a larger object need be examined. However, images produced from ROI data often exhibit severe density shading if they are reconstructed by unaltered 3-D X-ray CT algorithms (called Global methods here). These density artifacts can be so severe that low-contrast features are hidden. Time-consuming methods introduced previously to remedy these artifacts require specialized processing to replace or approximate the missing data outside the desired volume. Although these methods are required for true densitometry measurements, in many NDT applications only the detection of internal features or relative density variations is required. In such cases, the use of Local (or Lamda) X-ray CT, which produces an “edge-enhanced” reconstruction and requires only minor modifications of the standard 3-D X-ray CT algorithm, is recommended.