Measurement system for indirectly measuring defects

• US 20040242961A1
• Filed: 05/19/2004
• Published: 12/02/2004
• Est. Priority Date: 05/22/2003
• Status: Abandoned Application

• Current Assignee: Israel Aerospace Industries Limited (Government of Israel)
• Original Assignee: Israel Aerospace Industries Limited (Government of Israel)
• Inventors: Shitzer, Haim, Bughici, Iulian
• Application Number:
  US10/848,575
• Publication Number:
  US 20040242961A1
• Time in Patent Office: Days
• US Class Current: 600/108
• CPC Class Codes: A61B 1/07 using light-conductive means, e.g. optical fibres
• CPC Class Codes: A61B 5/1076 for measuring dimensions inside body cavities, e.g. using catheters A61B3/1005 takes precedence
• CPC Class Codes: G02B 23/24 Instruments or systems for viewing the inside of hollow bodies, e.g. fibrescopes
• CPC Class Codes: G02B 23/2469 using optical fibres

Abstract

A measurement system for indirectly measuring dimensions of a defect in a target area, within a range of working distances between the measurement system and the target area, the measurement system comprising illuminating optics for illuminating the target area, a laser pattern generator with a laser source and a pattern generating assembly for producing a reference laser pattern having at least one dimension essentially invariant within the range of working distances, the at least one dimension constituting a reference dimension in the target area, and projecting the reference laser pattern, alone a laser beam path, onto the target area, and an imaging system with imaging optics for obtaining an image of the target area together with the reference pattern, to determine the linear dimensions of the defect in the image relative to the reference dimension, wherein the laser beam path is spaced apart from the illuminating and imaging optics.

Claims

1. A measurement system for indirectly measuring dimensions of a defect in a target area, within a range of working distances between the measurement system and the target area, the measurement system comprising illuminating optics for illuminating said target area, a laser pattern generator with a laser source and a pattern generating assembly for producing a reference laser pattern having at least one dimension essentially invariant within the range of working distances, the at least one dimension constituting a reference dimension in the target area, and projecting said reference laser pattern, along a laser beam path, onto the target area, and an imaging system with imaging optics for obtaining an image of the target area together with the reference pattern, to determine the linear dimensions of the defect in the image relative to the reference dimension, wherein said laser beam path is spaced apart from said illuminating and imaging optics.

2. The measurement system according to claim 1, wherein the imaging system further comprises a camera for displaying and/or recording the image of the target area.

3. The measurement system according to claim 1, wherein the imaging system comprises an eyepiece for viewing the image.

4. The measurement system according to claim 1, wherein the laser pattern generator comprises collimator optics.

5. The measurement system according to claim 4, wherein the collimator optics are at the distal end of the laser pattern generator.

6. The measurement system according to claim 4, wherein the distal end of the laser pattern generator is disposed at the distal end of the measurement system.

7. The measurement system according to claim 4, wherein the reference pattern is circular.

8. The measurement system according to claim 4, wherein the reference pattern is annular.

9. The measurement system according to claim 8, wherein the laser pattern generator comprises a double-coned lens.

10. The measurement system according to claim 4, wherein the reference pattern comprises two characters whose centers are of a predetermined distance from each other.

11. The measurement system according to claim 10, wherein the laser pattern generator comprises two optical lines each generating one of the characters.

12. The measurement system according to claim 11, wherein the characters are cross-shaped and each of the optical lines comprises a gradient index (GRIN) lens.

13. The measurement system according to claim 1, wherein the imaging system is insertable in an endoscope having a working channel spaced from its optical axis, and the pattern generating assembly is housed in a conduit which is adapted to be integratable within said working channel.

14. The measurement system according to claim 1, wherein said measurement system further comprises an image analyzer/processor for automatically determining the size of the defect.

25. A measurement apparatus for indirectly measuring a defect within a target area comprising an endoscope and a measurement system according to claim 1.

15. A method for indirectly measuring dimensions of a defect in a target area, including:

illuminating said target area;

producing a reference laser pattern having at least one dimension essentially invariant within the range of working distances, the at least one dimension constituting a reference dimension in the target area;

projecting said laser beam pattern, along a laser beam path, into the target area;

imaging the target area together with the reference pattern;

determining linear dimensions of the defect in the image of the target area by comparing them with the reference dimension.

16. The method according to claim 15, wherein the linear dimensions of the defect are determined by a visual comparison of the laser pattern and the defect in the image.

17. The method according to claim 15, wherein the linear dimensions of the defect are determined by measurement of the image of the target area that includes the laser pattern and the defect.

18. The method according to claim 17, wherein the image is depicted in a photograph.

19. The method according to claim 17, wherein the image is depicted on a display monitor.

20. The method according to claim 15, wherein the linear dimensions of the defect are determined by analysis using a processor comprising an algorithm for same.

21. The method according to claim 15, wherein the range of working distances is at least 3 cm.

22. The method according to claim 15, wherein the reference dimension is considered to be invariant if its change within the range of working distances does not exceed 0.01 mm.

23. The method according to claim 15, wherein the reference pattern is in the form of either a circular or annular spot.

24. The method according to claim 15, wherein the reference pattern is in the form of two characters whose centers are of a predetermined distance from each other.