Laser products today have entered just about every area of the human environment. Laser products are used in medical treatment and diagnosis; in the home in entertainment products; in industry for material processing, process control, metrology and inspection; in communications; in the military in construction and agriculture for surveying and alignment; in physical, chemical and biological research; and in environ-mental protection and pollution control. The outstanding property of the laser that makes it so useful in so many applications, radiance, introduces a potential for exposure hazards that is somewhat unique. Because of the diversity of applications and hazard potential, the Bureau of Radiological Health, FDA, enacted a performance standard for laser products under the Radiation Control for Health and Safety Act of 1968. The following discussion will address the structure and requirements of the act and standard, and the organization and function of the agency in enforcement activities.

Adapting advanced technology to use by uninitiated operators in unorthodox settings can introduce unusual design challenges. In this paper, the author traces the development of an engineer's level which was especially configured for use by rice farmers in a unique surveying operation. The emphasis is placed on the changes made in the configuration of the equipment as improvements were made in adapting it to the user and the task. While drawing on his personal experiences which occurred prior to his present employment, the author crosses organizational lines to include advances made by competitive companies.

One of the measurable parameters of interest to experimenters who evaluate resolution characteristics of optical systems is the refractive index structure constant, C. During the last five years, several research programs have addressed the subject of measuring average values of Cn over paths of various lengths rather than performing point measurements with differential thermometers to determine C. These research programs have resulted in workable designs of instruments, but little has been done to evolve these designs into reliable and available commercial products. This paper relates the experiences involved in converting a well developed laboratory instrument into a configuration for use in the field.

This is a high-speed electrooptical system which can inspect from 2000 to 4000 parts per hour for scratches, pits, voids in seams, rust, and other surface flaws, and automatically reject unacceptable parts.

An electro-optical instrument to gauge automotive rear axle shafts is described. A high contrast image of the axle lug flange is projected via a high quality photographic lens on two self-scanning linear photodiode arrays. In one three-second rotation, a dedicated digital processor measures bolt circle location, hole diameter and separation. The unit automatically: compares each measurement with preset tolerances, computes the average bolt circle diameter, computes the bolt circle runout, makes a pass/fail decision, provides a digital readout, marks the axle shaft with colored ink and provides the operator a pass/fail light.

An, Instrument is described which inspects unpopulated, populated (components onserted and leads clinched), and soldered printed wiring boards for correct hole location, component presence, correct lead clinch direction and solder bridges. The instrument consists of a low power heliumneon laser, an x-y moving iron galvanometer scanner and several folding mirros. A unique shadow signature is detected by silicon photodiodes located at the optium geometry to allow rapid and reliable detection of components with correctly clinched leads. A reflective glint screen is utilized to inspect for a solder bridges. The detected signal are processed and evaluated by a minocomputer which also controls the scan inspection rate of at least 25 components or 50 components holes per second. The return of investment on this instrument for high volume production of printed wirind boards is less than one yea and only slightly longer for medium run military application.

Infrared optical systems, due primarily to military requirements, have made the transition from simple condenser optics which throw "heat" onto a discrete detector to diffraction limited imaging optics which are used to "view" in the infrared or illuminate high spatial resolution focal plane detector systems. Optically polished infrared lens element surfaces can be checked for sphericity and radius of curvature using conventional laser interferometry. However, the characterization of infrared material index of refraction homogeneity has been overlooked. To meet these newly emerging problems head on, Tropel developed TIRIS, the Tropel Infrared Interferometer System. The goal of this paper is to illustrate the importance of index inhomogeneity measurements by citing the degradation in performance (wavefront and Optical Transfer Function) of optical systems, caused by material inhomogeneities. A far infrared interferometer will be introduced, its basic construction outlined, and pertinent measurement parameters and formulas defined. Test results are shown of determining index inhomogeneity of two infrared transmitting samples.

An automated recognition system which utilizes a precision optical front-end, an electronic error-recog-nition system, an x-y table-positioning assembly and a printer was proposed, and a prototype model was constructed to prove its feasibility. The described system is capable of detecting line flaws and errors in conductor registration and in network characteristic impedance. The line-width information detected can be used both for impedance measurement and for detecting line flaws due to overwidth and underwidth conductors. Based upon performance, results show that the recognition system has good errordetecting resolution for all serious defects. It also provides a fast, reliable, practical method for measuring and testing printed wire width, thus solving a serious problem in manufacturing circuit boards for computer use.

An optical method for burr and thickness detection of superconductive braided cable was developed. Cables up to 0.128 inches thick can be tested. Thickness detector tolerance is adjustable in increments of 0.00025 inches. Wire burr fragments can be detected down to 0.001 inches in diameter.

A laser system has been fabricated for use in longwall coal mining operations to monitor the height of the last cut. This coal mine environment is particularly adverse to optics because of low reflectivity and surface inconsistency of the coal, as well as vibration, debris and explosion hazards.

A simple, low cost, reliable and non-electronic boresight tester was developed for use with military laser designators and range finders. Boresight testing is accomplished by attaching this device to the output end of a laser designator and checking the position of crossed green lines projected on the reticle pattern of the sighting telescope. The device uses a second harmonic generation (SHG) crystal and a corner cube reflector to convert a small portion of the infrared energy to visible green energy. This green energy forms a cross pattern imaged on the reticle by the objective lens of the laser systems under test. Cesium dihydrogen arsenate (CDA) was chosen as the best SHG for this application. Initial tests have shown the green cross pattern to be clearly visible and sufficiently bright far below the eye-safe level.

Modeling of electro-optical sensor performance with emphasis on the effects of smoke and aerosol in the path between target and sensor is discussed. The elements which comprise a simple model are presented along with characterization of propagation path effects. Design of an experiment to validate performance models is discussed with particular importance placed on the selection of targets to match sensor features. Data acquisition equipment and measurement techniques used for characterizing high bandwidth video signal synchronously with data characterizing the optical path are described.

Electro-Optical Systems, Test and Evaluation Directorate, USAMICOM, is currently involved in the Battlefield Obscurants Program evaluating laser designator and missile seeker systems when exposed to realistic battlefield conditions. Instrumentation was needed to provide information as to the position of the centroid of the laser spot after it had been attenuated and distorted as a result of those battlefield conditions. Current methods utilizing silicon vidicon cameras were not adequate due to the requirements of sensitivity and dynamic range comparable with the missile seeker performance parameters. This paper presents the technique, hardware development and software development, of a real-time, non-imaging, laser spot centroid tracker against both stationary and moving targets.

Shadowgraph and schlieren techniques have been used on board the NASA KC-135 low-gravity simulation aircraft to measure gravity-related fluid flow occurring in various experimental configurations. These configurations included cooled and solidified ammonium chloride and water, electrodeposited cobalt in CoSO4 solution, and immiscible and crystalmelt solutions. Hardware tests have also been performed for such critical optical system components as lasers and spatial filters to determine their performance and operation under low-gravity conditions. These test results will be used in the design of the various future Shuttle experiments which will utilize advanced optical measurement techniques. The design and configuration of the optical systems used to make these measurements and tests are presented, and the performance and operation of these systems and their components under low-gravity conditions are discussed. Some preliminary results are included.

A new, high. resolution, highly versatile CCD camera for industrial inspection applications is described. This camera is the second in a series of modular cameras (the first, A Modular TV Camera, was reported in 1979), and can be operated in the staring mode or in the scanning (TDI) mode. This paper describes the basic building blocks used to fabricate the camera, as well as a new 1904 x 48 virtual phase CCD sensor. Data relating to the performance of the sensor and the complete camera is presented.

Experimental results of a thermoplastic device for real-time IN-SITU recording, display, and retention of an in-line acoustic hologram is presented.

The development of the microprocessor and mini-computer for industrial process control has made the optical shaft angle encoder a natural choice for a position feedback transducer. Many of these applications, however, require the encoder to operate reliably in extremely hostile environments. In response to this, the encoder manufacturer has been faced with reliability problems which fall into the following general categories: 1. Exposure to weather 2. Wide operating and storage temperature range 3. Exposure to corrosive chemicals 4. Severe shock and vibration 5. High electrical noise levels 6. Severe blows to encoder housing 7. Operation in explosive atmospheres Three of these applications expose the encoder to most of these environmental conditions: 1. A jack-up control position feedback for an offshore oil well drilling rig 2. A depth measurement system for oil well logging instrumentation 3. Elevation and azimuth feedback for a solar power plant heliostat

The SL-3 flight on the NASA Space Shuttle will carry a 25 mW He-Ne laser holographic recorder for recording the solution growth of Triglycine Sulfate (TGS) crystals under low-zero gravity conditions. Three hundred holograms (two orthogonal views) will be taken (on SO-253 film) of each (rb3) growth experiment. Processing and analysis (i.e., reconstructed imagery, holographic schlieren, reverse reference beam microscopy, and stored beam interferometry) of the holographic records will be done at NASA/MSFC. Other uses of the recorder on the Shuttle have been proposed.

A theory is presented that predicts the effects of multiple scattering at small angles in the forward direction (less than 30 deg). An expression is developed to compute the fraction of light scattered exactly N times and the mean number of scattering as a function of transmission. The method of determining the mean-free-path for the total cloud is given.

Predictions of transmission in the visible (0.4 to 0.7 pm), mid-IR (3 to 5 pm), and far-IR (8 to 12 pm) wavebands based on measured transmission at 1.06 pm and simultaneously measured particle size distributions are compared with simultaneous measurement in the respective bands. Predictions are integrated over the waveband and transmittance ratios, calculated, and compared. Resolution and range requirements are presented for collecting particle size data.

A hybrid digital/optical joint transform correlator has been built for evaluation. The correlator uses a high resolution cathode ray tube, two Hughes liquid crystal light valves, and a Vidicon as the active input and output transducers. A digital frame store and formatter are used to store, format, and provide refresh to the CRT. The specially formatted input on the CRT is imaged on one light valve, whose output transform is written on the second light valve. The output of the second light valve is optically processed to produce the correlation plane on the output Vidicon. The optical correlation system is supported by a digital system which provides images from digital tape or analog tape to the frame store memory. The stored image can then be modified through the digital system for scale and rotation. The output of the correlation can also be digitized for further processing such as fixed pattern background subtraction. This paper describes the joint transform correlator, operating parameters, and future extensions that will overcome present limitations. Future applications of the optical correlation system as a peripheral to digital computing facilities will be discussed.

Binary holographic diffraction gratings were developed to shape laser-beam profiles and to generate multi-beam wavefronts for use in active infrared laser radar systems. The use of detector arrays in such systems requires amplitude and phase matching of multi-beam local oscillators to signal wavefronts in order to maximize the system's signal-to-noise ratio and resolution and to minimize the heat generated on the focal plane. In addition, a beam shaper in the transmit beam of the laser radar must shape the centro-symmetric Gaussian profile of the laser beam into a stretched profile that efficiently and uniformly illuminates the far-field footprint of the detector array. Potential applications include synthetic optical elements, high-energy laser-beam samplers, and uses in laser-beam annealing and optical communication.

A general purpose image recognition system has been developed for scene or symbol identification in unit material handling applications. The system is comprised of a photodiode array camera, a flash illumination unit and high-speed correlation computer. Black-white images are sensed by the camera during a 5 microsecond flash interval. These images are compared with a series of stored "template" images using the high speed correlation computer until a match is found. Images are identified at a rate of 300 per minute with a templage library of about 2,000 reference images.

The combination of a high resolution video system working with a spatial light modulator results in a system in which holograms can be produced and converted to electrical signals for the purpose of transmission to remote locations. The hologram is converted to an optical signal where the original image is reconstructed. This paper describes the proposed technique and shows some results from a laboratory experiment. The experimental results were obtained using a "General Electric Coherent. Light Valve" as the input transducer to the optical system.

The feasibility of using optics to measure inertial acceleration was investigated. The new concept was demonstrated using conventional optics in an open loop control mode. The experiements and analysis shows that the device is not resolution limited. This research study paves the way for the possibility of a new Strapdown Inertial System, an "Integrated Optics Strapdown Inertial System" utilizing a passive laser accelerometer and gyro, ideally implemented on a single "Chip" and a computer on a "Chip" which would allow the system to be packaged in a very small volume.