Thank you very much for such a welcome. I am very pleased... The reason why I came is not, as you said, that I have anything to offer to you, but because I was amazed, pleasantly amazed, at the fact that somewhere in the world there was enough talent and knowledge to gather such a symposium as you have done here, and I thought it was such a remarkable effort I just could not help coming with big eyes and big ears. Unfortunately, I can not stay long enough to participate in your discussions. I am very sorry.

Photography is demonstrated to be an effective tool in oceanographic investigation, especially for the study of water motions, marine biological organisms and sea-floor geological formations. However, the underwater environment presents many unique and difficult technological problems. A number of examples of how new photo-graphic techniques have been successfully used to record oceanographic phenomena are presented. These include studies of the movements of sea-surface slicks, surface waves, internal waves, turbulence, water turbidity, marine organisms, sea-floor relief, and the operation of equipment underwater. Still new photographic tech-niques are needed in these and other ocean-ographic studies.

The laser illumination techniques described permit spatial discrimination. That is, they allow the isolation and viewing of small volumes of space, while ignoring the scattering or the light which orginates elsewhere in the line of sight. These techniques allow an improvement in signal to noise illumination ratio in a wide variety of applications. The Atomic Wea-pons Research Establishment's original interest in this field was to enhance the discrimination against the self light of luminous shocks front beyond that given by narrow band illumination and viewing. However there are many diverse applications of spatial discrimination and there are other ways of obtaining spatial isolation. Some of these concepts are illustrated here by reference to the problem of seeing underwater where their help could bring economic benefits.

Ranges obtainable in underwater viewing are severely limited by backscattering. Increased ranges are possible by means of the range-gating technique, which gates out most of the unwanted backscattering electronically. Tests were conducted in filtered fresh water to determine the performance of a range-gating system and the characteristics of water in terms of image quality or resolution. A pulsed blue-green laser source and a highly sensitive receiver were used. Results indicate that range-gated systems are effective for underwater viewing up to 131 feet with good resolution. Comparison tests in a laser-illuminated ungated mode, a back-illuminated mode, and a front-illuminated mode were conducted concurrently.

In a previous paper by the author (Ref. 18) it was concluded that marine animals primarily use color and motion as cues for visual performance almost exclusively, in contrast to land animals who use shape, size and distance stimuli as cues, although they have structurally similar eyes. This paper explains to what extent marine animals use color and motion stimuli as opposed to shape, size and distance as cues in marine environment. In the paper the behavioral measurements method was emphasized.

Problems encountered in underwater documentation with electro-optical (television and photographic) image-recording systems were examined during an underwater documentation project conducted at the Naval Missile Center, Point Mugu, California during the summer of 1967. Photographic records of resolution targets and color targets under water were compared with visual sightings of the same targets by a diver at the same point of observation. Comments of the diver while observing a target array and comments of a technician observing the same targets on a television monitor at the surface are presented to compare their simultaneous interpretations of target images.

All the reasons for obtaining photographic coverage of scientific operations conducted on the ground or in the air are even more valid for underwater operations.

A program to obtain an optimum system of stereo-photography has been developed which provides complete relief maps from portions of the ocean floor. The program to develop this stereo-photogrammetric system has been sectioned into two phases: a preliminary field test with a "wet" submersible; a final test with a "dry" submersible. The preliminary test phase has so far demonstrated many problem areas but also provides encouraging results: e.g., lens distortions are of the same magnitude as the typical metrogon aerial camera lens; a manned wet submersible can maneuver sufficently to completely photograph a test area of over 2,500 square meters from an altitude of 10 meters above the bottom with at least 56 percent overlap and 15 percent side lap; a block of over 50 photographs which covers this area can yield a complete horizontal solution ( 9 points per photograph) with only 5 ground control points, and vertical bridging is possible on existing photographic equip-ment. Early experiments have shown that while the final phase is feasible, considerable work remains to be done in improving camera systems, positioning systems, and submer-sible performance. This final phase, conducted from a dry submersible, will require a new approach since ground control points are virtually impossible to obtain. Orientation of the photographs will be extrapolated from the submersible's attitude and position.

This paper describes the successful utilization, of a closed-circuit underwater video system in a deep ocean engineering project to emplant an underwater acoustic source at a precise location on the ocean floor at a depth of 300 fathoms. The system, consisting of camera, lighting, pan and tilt unit, control unit, power supply, four monitors,. a video film recorder, 5000 ftof cable on a special cable reel, and a slip ring assembly, was used to position the acoustic source safely and properly. in its subsurface location. The video system monitored the descent of the acoustic device con tinuously so that the operation of touchdown and emplacement was under observation at all times. The system provides for periodic observation of the acoustic source and its structuri members at will during its period of intended usage.

Slides and motion picture excerpts were used to demonstrate some applications of photography in the study of fish behavior. The problems of avoidance of a purse seine net by fishes, the associations of fish with floating objects, shark behavior, and fish schooling behavior served to illustrate the techniques. Special methods were discussed such as time-lapse photography to record changes in patterns of behavior and infrared photography to observe schools under low illumination.

A deep-sea camera system has been developed for observing events on the deep ocean floor for time periods as long as 100 hours. This lightweight system has principally been employed to observe deep benthic organisms. In this use, it freely descends to the ocean floor, where it is maintained by a ballast weight surrounded by bait. Lured into the field of view of the camera by the bait, the creatures are photographed at preset intervals. At a preselected time, the camera system is separated from the ballast weight and ascends to the surface for recovery. Photographs have shown large numbers of active organisms to depths of 20,000 feet, including large predators.

Almost twenty years ago, we were called by the French Submarine Alpine Club to adapt to Deep Sea Scuba Underwater Photography our new high-speed pulse camera with "Strobe", the "Torpedo" lighting system,originally developed by us for model tank propeller cavitation research at the Paris and Wageningen model tanks. Our earliest single assembly system was immediately successful in producing the first and only really sharp and color-correct underwater photos of marine life, geology and archaeology. It was fully effective only because it was designed as a complete integrated system with each component subsystem, camera, corrected lens, strobe light, controls and housings simultaneously designed for each other to fully accomplish the required job. This basic underwater systems engineering concept is the essential design philosophy of the modern Pegasus Photographic Systems applications described hereafter.

One of the most fundamental optical measurements which can be made in natural waters is the measurement of the radiance distribution of natural radiant energy as a function of depth. Radiance distribution data is an important input to the theory of radiative transfer for the study of electromagnetic radiation within the sea, it provides a biologically meaningful technique for measuring the radiant energy supporting the ecology of natural waters and, of more immediate interest to SPIE members, the radiance distribution leads directly to the determination of the inherent contrast of an object for any path of sight. Knowledge of the inherent contrast makes it practical to apply the equations of contrast reduction to the problems of underwater visibility. Without radiance distribution data, the inherent contrast must be assumed or measured directly neither of these has proved satisfactory in practice. This paper describes a proposal to record the radiance distribution of natural light underwater by a method employing a "fish-eye" camera, having a 180° field of view. From the films obtained, values of radiance can be determined by methods of photographic photometry. In addition, the application of radiance distribution data to the problem of determining the contrast of underwater objects is discussed.

The requirement for an accurate optical profile of the sea from the surface to 6500 meters initiated the design and construction of the Navy Underwater Sound Laboratory's deep sea transmissometer. The instrument is a 4-meter, single-path, non-collimated, optical transmissometer capable of transmitting data to the surface by cable or automatically recording it in a self-contained package. This paper describes the design, construction, and calibration of the transmissometer and the data obtained in the North Atlantic Ocean to depths of 5100 meters.

This presentation concerns two new instruments and a refinement of an old instrument. Together they permit the absorption, total scattering, and back-scattering coefficients to be measured quickly and fairly simply. A fourth instrument with which we hope to measure very narrow angle forward scattering will also be described.

An improved illuminometer system is described which consists of a dual underwater illuminometer and a deck illuminometer both having improved light collecting properties and a new deck measurement unit. The instrument can provide direct measurements of (1) the illumination on the ocean surface, (2) the ratio of the downwelling illumination in the ocean to that on the ocean surface, (3) the ratio of the upwelling to the downwelling illumination in the ocean, (4) diffuse attenuation coefficient, K, for the downwelling light field, and (5) the depth of the underwater sensor. Emphasis in the design of the equipment has been to provide a system with which the operator can quickly obtain direct, accurate settings and to minimize the opportunity for human error in reading the results. The design philosophy of the lambertian light collector and the photoelectric circuitry is given along with the resulting performance. Examples of the data obtained with this system and its applications are given.

A transmissometer developed at the Visibility Laboratory, University of California at San Diego is described. This instrument is capable of being operated by nontechnical persons with little instruction. No compromise has been made in the precision of measurement to obtain the design objectives which include ease of operation, low maintenance and reliability. The optical system, Which has a cylindrically limited beam rather than a collimated source of light, is discussed.

A free-flooded, high intensity under water searchlight consisting of 2.2 kw xenon short-arc lamp mounted at the focus of a 10-inch diameter reflector has been developed at the Naval Research Laboratory. The unique feature of the searchlight is that both the lamp and the reflector are in direct contact with water; neither one is surrounded by a water-tight enclosure as is often the case for underwater light sources. Thus, many of the disadvantages of an enclosure such as added weight and bulk, heat transfer problems, window breakage, and inaccessibility of the light source interior are overcome.

To date, examined evidence of color perception deals with pigments of low reflectance values, and as evidenced with increased depth, decreasing light level, plus water density, rapid absorbtion of the infra unit occur (ie. color rendition S.P.I.E. February 1967, E. Brooks II). High reflective units are revealed in this paper to determine added efficiency to the recording underwater observer and camera receiver. Ambient levels to low and high pigments in close and extended distances. Supplementary lighting evaluation on targets utilizing quartz iodine, thalium iodide, and magnesium for evaluated image enhancement and increased color penetration of the water barrier on large targets equaling 80 square feet of surface.

A significant amount of work has been done in the study of underwater lighting to optimize light sources for underwater photogtaphy, television, and human observation, Many different lights have been developed, but only three types are being utilized to much extent at the present time,they are; the incandescent quartz iodide light; the mercury vapor light; and the recently developed, thallium iodide light. Each of these lights have characteristics which optimize it for different underwater lighting applications.

The combined aberrations of a concentric dome and a lens are discussed. It is shown that a major part of the aberrations cannot be directly attributed to the dome,but is caused by a drastic change in conjugates, which the dome imposes on the lens. Modulation Transfer Curves are presented for comparing the image quality of a highly corrected conventional photographic lens behind a concentric dome with the image quality of a dome-lens combination with integral correction. It is shown that the first approach should only be used for small apertures and field angles.

A technique for performing image processing in real time on normally illuminated scenes--and its potential applications to underwater search and visibility improvement--are described. The Cybercon, a system embodying this technique, is currently undergoing terrestrial tests for the U. S. Army. The system consists of an electro-optical sensor under programmed electronic control. Image processing is performed in a special camera tube. Results are visible to the operator at the phosphor viewing screen of the unit, or may be transmitted to a remote display. Tests on simulated backscatter penetration have been performed, and are illustrated in the paper. This is accomplished by high-pass filtering of the visual image. A 2:1 increase in visibility range is estimated. For underwater search applications, the Cybercon sensor may be programmed to detect the particular shape or spectral characteristic desired. An example of this type of shape detection performed on underwater photography is presented. Automatic monitoring for motion or changes within the scene, together with visibility improvement, can be performed by this sensor used as a processor. Terrestrial examples of this type of application are presented.