Телевизионный Интерференционный Голографический Регистратор ТИГР на английском

Holographic TV Interferometer for Non - Destructive Testing

Veronika Babenko, Simon Gurevich, Nikita.Dunaev, Dr. Vladimir Konstantinov,
Vladislav Levushkin, Ekaterina Smirnova.

Problem

It well know as that during the space station flight the windows become less transparent after a long time period. There are several factors which can influence on the windows transparency. The first one results from the depositions of the materials which were evaporated on the outside surface of the spacecraft construction. Damage may be caused by small particles, micro-meteors and solid fragments which are flying around the station and can scratch the glass surface. For appropriate protection measures it is necessary to determinate the influence of the flight condition on the optical characteristics of spacecraft windows. The visual observation of the windows by crew members as well as ordinary photos do not get exhaustive information.

Description of the TV Holographic interferometer

TV holographic interferometer (320x320x640 mm, 25 kg) includes: He-Ne laser (0,6328 mm), optics, scanning system, tuning system, TV camera. The recorder gives possibility to produce the visual observation of magnified contrast images of the phase defects on the outside surfaces of window.

The field of view is about 10x10 mm. To get images of large size objects (up to 20 cm in diameter) a scanning system is used. The visual observation gives the possibility to adjusting the optics and select the desired area of the window. The TV camera is used for recording the images for further digital processing. It is also possible to record an image on a photographic film. The device gives the opportunity to record the defects (micro-meteor trace and dimness of spacecraft window), measure their dimensions, to make a hologram and to produce the interferometer's evaluation.

Mode of operation

In the process of working an enabling a recorder in following events possible:

at incoming control

under autonomous check (without TV and with it)

when functioning (working) on board of a spacecraft (without TV and with him)

Functioning the TV interferometer in real conditions is realized in regimes:

measurements of sizes of defect

taking pictures a defect

registrations of hologram of defect

interferometer

Interferometry bands can be observed:

Visual

By means of CCD-cameras

The sizes of craters lie within the limits of 10 - 50  . Their depth ranges from several microns to millimeters. The defects in a form of scratch or a fragment are due to the strokes micro particles with the velocity 2-8 km/c.

Types of distinctive defects of external surface of glass of station ?MIR¦ window.
(scratch, micro-meteor track and contamination)

The hologram is a record from which one can obtain information about the geometry and optical properties of the object and the quality of the surface. All the processes and materials investigated by the interferometer can be calculated with the help of special program on computer. The process of isolating and numbering the skeletal lines on the interferogram is automated /4/.

Conclusion

Another field of the application of our interferometer is non-destructive testing in industry. For example, it may be used for testing parts of precision tools, products in microelectronics industry (semi-conductor plates),optical fibers, optical components, vibration control, for registering modulation of speckle patterns, etc.

The main result of this work was presented at The 4 International Workshop on Automatic Processing of Fringe Patterns, Bremen, Germany.

References

/1/ Gurevich, S.; Dunaev, N.; Konstantinov, V.; Pisarevskaya, S.; Chernykh, D.: Compact holographic device for testing of phisico- chemical processes under microgravity conditions. Proced. of Microgravity Science Simposium, (AIAA/IKI), Moscow (1991), 351-355.

/2/ Gurevich, S., Konstantinov V.,Chernykch D.: Interference- holography studies in space. Proc. SPIE, 1183(1989), 479-485.

/3/ Gurevich, S., Konstantinov, V., Relin, V., Babenko, V.: Optimization of the wavefront recording and reconstructing in real-time holographic interferometry. Proc. of SPIE, 3238(1997), 16-19.

/4/ Bat'kovich, V., Budenkova, O., Konstantinov, V., Sadov, O., Smirnova, E.: Determination of the temperature distribution in liquids and solids using holographic interferometry, Tech. Phys., 44(1999)6, 704-708.