Abstract

A modification of schlieren optics was explored as a technique for industrial gas-leak detection. A high-contrast pattern on thin reflecting material was imaged with a zoom lens onto a negative of the same pattern as a method of eliminating the ordinary rays. The geometry of the industrial setting determines the useful spatial frequency of the pattern.

© 1996 Optical Society of America

Full Article  |  PDF Article

References

  • View by:
  • |
  • |

  1. For a collection of key papers see J. R. Meyer-Arendt, ed., Selected Papers on Schlieren Optics, SPIE Milestone Series, vol. MS61 ~The International Society for Optical Engineering, Bellingham, Wash., 1992!.
  2. E. Hecht, A. Zajac, Optics ~ Addison-Wesley, Reading, Mass., 1979!.

Hecht, E.

E. Hecht, A. Zajac, Optics ~ Addison-Wesley, Reading, Mass., 1979!.

Zajac, A.

E. Hecht, A. Zajac, Optics ~ Addison-Wesley, Reading, Mass., 1979!.

Other (2)

For a collection of key papers see J. R. Meyer-Arendt, ed., Selected Papers on Schlieren Optics, SPIE Milestone Series, vol. MS61 ~The International Society for Optical Engineering, Bellingham, Wash., 1992!.

E. Hecht, A. Zajac, Optics ~ Addison-Wesley, Reading, Mass., 1979!.

Cited By

OSA participates in CrossRef's Cited-By Linking service. Citing articles from OSA journals and other participating publishers are listed here.

Alert me when this article is cited.


Figures (7)

Fig. 1
Fig. 1

Standard schlieren optics.

Fig. 2
Fig. 2

Test results of standard schlieren. An inert gas duster is sprayed from the right, and turbulence from the expanding jet is observed. Before the spray a dark field exists with bright bands at the mirror edges from spherical aberration.

Fig. 3
Fig. 3

Zebra schlieren optics. An illuminated high-contrast stripe pattern is precisely imaged onto its negative ~Ronchi ruling!. Ordinary rays are blocked, and deviated rays form an image of the disturbance farther back. This image is viewed with the CCD camera.

Fig. 4
Fig. 4

Zebra schlieren optics and the illuminated zebra pattern. This setup is based on Fig. 3. The projector, consisting of a lamp and a lens, is in the foreground. The imaging system is in the background with the camera removed.

Fig. 5
Fig. 5

Test results of zebra schlieren. An inert-gas-duster nozzle is placed just in front of the zoom lens.

Fig. 6
Fig. 6

Geometric considerations for zebra schlieren.

Fig. 7
Fig. 7

Estimate of expected deviation from the He leak. The plot presents a ray deviation for a range of incident angles and prism angles that the majority of rays are likely to encounter.

Equations (3)

Equations on this page are rendered with MathJax. Learn more.

x $ w y f,
x $ L 2 R y f .
f 5 u 2 a 1 sin 21 @ sin a n 2 2 sin 2 u! 1 y 2 2 sin u cos a#,

Metrics