X-RAY MAPPING OF FLAWS BY COMPUTER GRAPHICS

A NEW PROCESS THAT GIVES A THREE-DIMENSIONAL PICTURE OF THE SHAPE AND LOCATION OF INVISIBLE DISCONTINUITIES (GAS HOLES, CRACKS, ETC.) IN METALLIC OR NONMETALLIC MATERIALS HAS BEEN REDUCED TO PRACTICE. TWO X-RAY FILMS OF THE DEFECTIVE STRUCTURE ARE TAKEN FROM DIFFERENT ANGLES, WITH A PROVISION FOR ACCURATE REGISTRATION BETWEEN THEM. A STANDARD WEDGE OF THE SAME COMPOSITION IS X-RAYED SIMULTANEOUSLY. DENSITY READINGS-OBTAINED FROM MICRODENSITOMETER SCANS AT GIVEN INTERVALS-ARE CONVERTED INTO THICKNESS VALUES, WITH A CORRECTION FOR SCATTERING IF NECESSARY. THE RESULTING DATA ARE DIGITIZED AND PUT ON TAPE. THIS IS FED INTO A SPECIALLY BUILT SHAPE RECONSTRUCTION COMPUTER, WHICH, BY MEANS OF A NOVEL SUPER-POSITION ALGORITHM, COMPUTES FOR EACH SCAN THE CROSS SECTION OF THE DEFECT AND DISPLAYS IT ON ITS CATHODE RAY TUBE. TAPE FEED, COMPUTATION AND PHOTOGRAPHY OF THE CRT DISPLAY TAKE ONLY A FEW SECONDS. A SERIES OF CROSS SECTIONS YIELDS A THREE-DIMENSIONAL PICTURE. SAMPLES OF SHEET ALUMINUM AND WELDS CONTAINING DEFECTS WERE ANALYZED IN THIS MANNER. VERY GOOD AGREEMENT WAS OBTAINED WHEN COMPUTER- DERIVED PICTURES OF THE SHAPE AND LOCATION OF THE DEFECTS WERE COMPARED WITH PHOTOGRAPHIC ENLARGEMENTS OF THE SECTIONED SAMPLES. /AUTHOR/

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/00255327
• Supplemental Notes:
  • Vol 27, No 8, PP 169-179, 23 FIG, 1 TAB, 11 REF
• Authors:
  • Hartmann, F
• Publication Date: 1969-8

Media Info

• Serial:
  • Materials Evaluation
  • Publisher: American Society for Nondestructive Testing
  • ISSN: 0025-5327

Subject/Index Terms

• TRT Terms: Cathode ray tubes; Computer programs; Defects; Densitometers; Inspection; Materials; Materials tests; Nondestructive tests; Photography; X ray analysis
• Uncontrolled Terms: Discontinuity
• Old TRIS Terms: X ray inspection
• Subject Areas: Geotechnology; Highways; Materials;

Filing Info

• Accession Number: 00216871
• Record Type: Publication
• Files: TRIS
• Created Date: Sep 29 1994 12:00AM