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Quantitative results concerning TV-holography and shearography associated with endoscopy are presented here. In both cases, a c.w. argon laser has been used. Moreover, shearography experiments have been performed with the help of a pulsed YAG laser working at 25 Hz.

Quantitative measurements were achieved using different techniques associated with an imaging bundle fiber:1.double-reference beam holography method with c.w. or pulsed laser, 2. TV-holography with c.w. laser, 3, shearography with cw, or pulsed laser, 4, real-time holographic interferometry with a repetitive frequency-doubled YAG laser working at 25 Hz,Deformations of a loaded aluminium plate or a rubber membrane were calculated using image processings. _1. INTRODUCTIONQualitative holographic endoscopy has been performed for many years1. In recent publications, it has been shown that quantitative measurements were possible. Different techniques have been employed: eridoscopic profilometry using a projected grating on the object2, double-reference beam holographic interferometry3, TV-holography and shearography4. This paper presents a synthesis of two papers in printing3' . Diverse endoscopes, either supple or rigid, were used. We report here the results obtained with an imaging bundle fiber. It is composed of 80,000 elementary fibers arranged in a square of 4 x 4 mm2 . The length of the bundle is one meter and the core diameter of each fiber is 10 /tm. The filling ratio of the bundle is approximately 50%.The object is illuminated by a laser beam passing through a multimode fiber. In some experiments this fiber is not necessary to light the object.A microlens forms an image of the object on the input face of the endoscope. The image carried on the output face oF the endoscope is then regarded as an object in the different experiments described hereafter, i.e. 1. double-reference beam holographic interferometry, 2. TV-holography, 3. shearography, 4. real-time holographic interferometry.A c.w. Ar laser and a pulsed YAG laser were used as light sources. All techniques are described with their components and typical results are presented. 2. DOUBLE-REFERENCE BEAM HOLOGRAPHIC INTERFEROMETRY5 Fig. I shows the recording set-up. The reference beam is split in two parts with the help of a Michelson interferometer. Each exposure is recorded successively in time with its own reference beam by using two shutters placed close to the two mirrors of the Michelson interferorneter. 0-81 94-0905-7/93/$4.00 SPIE Vol. 1732 Holographics International '92 /481 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 07/03/2016 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx