In image processing, digital systems give the highest flexibility in the sense that they allow in general to solve many problems by only changing software.

How to earn over $100 million a year by investing $40 million ? No this is not the latest Wall Street "tip" but the costsavings obtained by the U.S. Department of Defense. 2 % savings on annual turnover claim supermarkets ! Millions of Dollars saved report automotive companies ! These are not daydreams, but tangible results measured by users after implemen-ting Automatic Identification and Data Collection systems, based on bar codes. To paraphrase the famous sentence "I think, thus I am", with AI/ADC systems "You knonw, thus you are". Indeed, in today's world, an immediate, accurate and precise information is a vital management need for companies growth and survival. AI/ADC techniques fullfill these objectives by supplying automatically and without any delay nor alteration the right information.

A description is given of an installation which makes it Possible to manage the cutting into Plates of float glass emerging from the annealing tunnel of a production unit, taking account of the pre-established quality criteria and the requirements imposed by the order book. This unit comprises first of all a device for detecting volume defects, based on scanning of the strip by a laser beam, which makes it possible to obtain, in real time, an electronic image of a section of the strip, showing the position and dimensions of the various defects. Secondly, this image is used in a data processing device which allocates to it an optimisation algorithm which Provides an optimal cutting diagram taking account of all the quality characteristics and the reauirements of orders. All the onerations are carried out fairly quickly, so that the cutting un can be controlled by the computer which, by another route, also controls sending of the cut sheets to the various packing stations, each corresponding to a different customer. Finally, this same computer checks the actual packaging of the cut sheets of glass.

Photoelectric sensors have various merits over mechanical sensors such as microswitches and limit switches because a photoelectric sensor detects an object without physical contact. Here are some of the features photoelectric sensors offer:

The booming progresses of machine vision is very well reflected by the amount and the quality of the papers that are published weekly on that topic. The rate of introduction of machine vision on the shop floors is far less impressive. Resistance to change should not be invoked exclusively to explain that paradoxical situation. Central to that problem, is the communication gap between the hi-tech experts, who propose dramatically new solutions to traditional problems, and the production managers, too exclusively concerned with their sole production technologies. The focus of this paper is on inspection and control. Guidelines are provided - to identify the most promising applications for machine vision, inside a manufacturing plant, - to evaluate them versus human inspection and - to compare the various advantages and limitations of the currently available systems.

This practical application explains how a digital theodolite is used daily to gather and registrate all the topographical data and measurements, on the site. The registrations are computed in a line of data processing to obtain, as a result, a detailed, scaled and accurate map, nearly automaticaly. Onto this map, the company registrates the lying of the cables, of the pipes and most of the technical components of the gas and electricity networks

ISIS is a non-invasive optical method for obtaining topographical data of the human back shape. It is used for the follow-up of scoliosis (spinal deformity). Using the ISIS, the number of x-ray photographs can be reduced in the scoliosis clinics.

Extensometry is composed of all the techniques available for the measurement of the local state of STRAIN at one or various points of the surface (or in the volume) of a structure. The behaviour of the structure submitted under a sollicitation, is characterized by the 3D state of STRESS and the CONSTITUTION LAWS of the material. This state of stress is calculated from the strain measurements related to the stress components by those laws of constitution. At each point the deformation is not the same following any direction and the total information on deformation requests a sufficient number of strain measurements. LONGITUDINAL and SHEAR strain components are disponible for this, but generally only longitudinal strain c are measured: as shown on Figure 1 a longitudinal strain ε is a relative displacement between two points.

In this paper, we describe an application of cross-correlation techniques aimed to the improvement of the sensitivity of a laser interferometric vibration sensor. The interferometer operates remotely from a moving target without requiring retro-reflective mirrors. It is a polarizing interferometer based on a Michelson scheme with a short internal reference path and a long external path which projects to the target through a telescope (Fig. 1). The same telescope collects the laser light scattered back from the target. Any surface is suitable: concrete, metals, bricks, etc. The surface roughness provides the scattered light which is used by the interferometer. The power of the projecting laser light (X = 632.8 nm) is kept below 5 mW for safety reasons. The interferometer operates up to 200 meters away from the target and is optimized for vibration measurements in the range 0.1-150 Hz which is suitable for tests of large civil structures. A detailed description of the interferometer and some examples of field applications are presented in Ref. 1 and 2. In Ref. 1 the sensitivity of the interferometer is discussed in terms of various sources of noise. The atmospheric turbulence gives the largest contribution since the random fluctuation of the refractive index along the propagation direction is detected by the instrument as target vibration. The effect of the beam wandering in the atmosphere due tue turbulence, has been efficiently reduced by an opto-electronic beam steering loop built in the interferometer. The overall average sensitivity in oscillation amplitude measurements performed at 100 meters away from the target is of the order of 0.1 microns. An exem-ple of the frequency domain behaviour of the turbulence effect in real environment is shown in Fig. 2. The data are obtained by aiming the interferometer to a fixed point on a rock 150 meters away. The spectral behaviour is roughly of the type 1/f. The idea described in this paper is to use two identical interferometric vibration sensors pointing to the same target from simmetrical remote positions and cross-correlate the two measured vibration signals. This configuration was experimentally tested in the laboratory on a simulation system and then used for in field measurements. The obtained results show a good reduction of the turbulence background noise allowing an ultimate sensitivity of the order of 0.01 microns.

After a recall of principles and applications of the "CMC" method which is able to compensate and consequently to measure any motion of any amplitude of an object in holographic interferometry, we describe different ways to obtain readable interference fringes prior to get the infinite fringe. Finally, we give some ideas to study high-speed rotating objects with the help of the double-exposure technique.

The originality of this new visualization system offers the following advantages great visual comfort due, to the preservation of the real dimensions, great comfort of position for the observer; the eyes are no longer riveted to the eye-pieces.

Author describes a doubled pulse yag laser manufactured by SOPRA and indicates information of results reached by the Laboratoire de SAINT-LOUIS. Described double pulse yag laser is issued of monomode frequency doubled yag laser and can be used in Holography as a very attractive source.

To-day, fiber optics' low linear attenuation (0.5 dB/km at 1300 nm for fibers with dia 50 pm index gradient) enhances the growing significance of junction loss. Indeed, the transmission system's range is 2 km shorter, which is generated by every 1 dB connection! The optic connector is a compact device allowing links between 2 fiber optics or between 1 fiber and an optoelectronic component to be generated or cut off repeatedly while providing minimal transmission's crosstalk. After studying the various characteristics generating crosstalk, the alternatives selected by RADIALL relating to miniature optic connectors shall be considered.

As quoted in several technical books [1] adhesively-bonded joints are rarely used, because of their low strength and of their poor design. As remarked in the review-paper due to Benson [2] , the main difficulty is to compute the effect of the angular singularities in the neighbourhoods of each extremity of the lap. The two singularities have been examined by means of the matched asymptotic expansions method [3], due to Gilibert and Rigolot. But it was rapidly seen that this method was not able to explain the behaviour of the samples tested, when the width of the joint is small versus the geometrical and mechanical characteristics of the adherends. The aim of the present paper is to give a good experimental approach of the singularities effects by use of the laser-photoelasticimetry analysis. In a first step we compare the results with the classical ones obtained by Gilibert [4] by an extensanctrical method; it is in particular possible to evaluate the residual stresses due to the machining processes. In a second step we compare the results with the theoretical ones obtained by Gilibert and Rigolot [3]; in particular a dissymmetry in the localisation of stresses is to be seen and not yet explained by the computations.

An electronic device has been developed stabilizing within 2 ns the delay of the light output of a pulsed nitrogen laser in long time operation.