The unaided human eye with its inherent limitations serves us well in the examination of most large-scale, slow-moving, natural and man-made phenomena, but constraints imposed by inertial factors in the visual mechanism severely limit our ability to observe fast-moving and short-duration events. The introduction of high-speed photography (c. 1851) and videography (c. 1970) served to stretch the temporal limits of human perception by several orders of magnitude so critical analysis could be performed on a wide range of rapidly occurring events of scientific, technological, industrial, and educational interest. The preferential selection of eye, film, or video imagery in fulfilling particular motion analysis requirements is determined largely by the comparative attributes and limitations of these methods. The choice of either film or video does not necessarily eliminate the eye, because it usually continues as a vital link in the analytical chain. The important characteristics of the eye, film, and video imagery in high-speed motion analysis are discussed with particular reference to fields of application which include biomechanics, ballistics, machine design, mechanics of materials, sports analysis, medicine, production engineering, and industrial trouble-shooting.

South Africa has been welcoming visitors on a regular basis since the early 1850's when the mail contract was awarded to the General Screw Steam Shipping Company to provide a monthly service from England to Cape Town. In fact, the inaugral service arrived in Cape Town on the 27th January 1851 when the RMS Bosphurus arrived in Table Bay after a forty day journey. The passenger fare was the equivalent of R58,00 or +- US $27,00. If we can think of that journey in terms of time and money, it would be exactly the inverse to the trip experienced by overseas delegates to this Congress.

High speed photography is used to assist research into the fundamentals of blasting in underground gold mining stopes. A suitable lighting system has been developed for use underground. Two or more banks each comprising twenty flash bulbs are positioned within 3 m of the blast. Using a remote flash-sequencer, the flashes are fired with millisecond accuracy. The flash-sequencer is microprocessor-based, is safe and reliable, and offers a wide selection of illumination levels. Illumination levels of 28 x 10⁶ lumen-seconds are easily obtained, and can be exceeded. The lighting system is battery powered, portable, and able to withstand rigorous underground conditions. The system has enabled illumination of over 20 test blasts, and will be used extensively in future underground blasting investigations.

A system for high speed photography of underground blasting with 16 mm rotating-prism cameras has been developed for the explosive rock break-ing research program in gold mine stoping at the Chamber of Mines Research Organization. This photographic system is a powerful research tool which has greatly enhanced understanding of the blasting process as it provides a visual account of the course of events following explosive initiation. The techniques which provide long duration viewing by means of controlling the expulsion of dust laden gases from the blast hole are presented. Also covered are the camera protection measures which enable camera placement within three metres of the blast. A lighting system consisting of expendable flashbulb banks coupled to a microprocessor based sequence controller has been developed and is described in a companion paper by Holden. Generalised accounts of the blasting process and specific findings from photographic studies are discussed.

Recordings with the "Open View Streak Technique" supply the full spatial as well as a highly time-resolved information about an event. Studies on simultaneous initiation devices (SID) are presented as an example. Such recordings can be made with a rotating-mirror streak camera, the streak slit of which can be removed, or also with an image converter camera, in this example with an IMACON type camera. The streak records give an exact information on the time and location at which a detonation in a channel is interrupted. Thus; Open View Streak Technique provides a means of detecting and eliminating sources of failure in the design and manufacture of such SID arrangements. This analog record makes it also possible to determine the detonation velocity during the entire event and in the individual portions of the path of propagation.

Resolution in space can be improved considerably with the wedge technique. A prerogative is, however, that the event proceeds uniformly across the plane of the wedge. Arrangements are in general chosen so that the event must arrive at the wedge simultaneously. This involves the use of highly accurate and elaborate plane wave generators. The present paper proposes to use a method that permits measuring both the time of arrival of a shock or detonation wave and the arrival of the shock wave after a certain distance of propagation, which can be recorded continuously along the wedge. However, the wedge material must be transparent. By means of the multi-streak-technique, the shock velocity can be observed as a function of the thickness of the wedge across a larger plane. In this way, phenomena can be observed and recorded not only when the wave front is plane, but also when the phenomenon is converging or diverging.

Novel opto-electronic techniques for dynamic high pressure studies are presented: a) A thin layer of explosive powder is spread over the surface of shocked material and detonates with the shock arrival. Light is emitted and can be recorded optically with a streak camera or electrically through an optical fiber and a photomultiplier. The optical fiber can be in contact with the explosive powder or can collect the light from a distance without interfering with the recorded phenomena. b) A quartz fiberoptic placed in direct contact with a shocked surface self generates a light impulse. Coupled to a high speed solid state amplifier it can be used as an extremely simple "optical pin" and possibly as a pressure transducer.

Stimulated Raman scattering in hydrogen, produced by typical short-pulse lasers, exhibits strong transient features when operating at low pressures. These effects, relating to Stokes pulse shape, pump and medium depletion and conversion efficiency, were investigated theoretically and experimentally. The results enable us to explain this behaviour and to quantify the intensity levels and time scales where conversion is adversely affected.

The formation, distribution and spectral properties of nanosecond surface corona discharges have been investigated. The discharges were initiated by fast-rising voltage pulses CdU/dt > 5x10¹² V/s) in atmospheric' pressure air and nitrogen. Time-resolved measurements using sensitive photographic and photomultiplier techniques have shown that surface corona discharges can be established on the nanosecond time scale and can be distributed uniformly over large areas. Propagation speeds of up to 10⁷ m/s have been measured. Spectrally resolved measurements show enhanced light emission at vacuum uv wavelengths below 140 nm. Due to these unique properties surface corona discharges can be used in applications such as large-area plasma electrodes and uv preionisation sources for high-pressure gas discharge lasers, nanosecond light sources for spectroscopy and high-speed photography as well as in multichannel surface discharge switches for low-inductance high-voltage switching.

A temporal analysis of a linear system is given. Through specific analytical pulse shapes, general principles of pulse shaping are deduced. A commonly used optical device in the pulse compression technique, the so-called Treacy's grating pair, is re-examined and its corrected group delay and dispersion are re-derived. The main features of this device, relevant to pulse compression, are also presented

During radiographic experiments involving explosives, it is valuable to have a method of monitoring the X-ray flux ratio between the dynamic experiment and an X-ray taken of a static object for comparison. The standard method of monitoring with thermoluminescent detectors suffers the disadvantages of being sensitive to temperature, shock, UV radiation, cleanliness and saturation. We are studying an additional flux monitoring system which is not subject to any of the above disadvantages and is based upon the ⁶³Cu(photon,n)⁶²Cu reaction. The ⁶²Cu has a 10 min. half-life and is counted by a nuclear pulse-counting system within a few minutes of an explosive test. 170 microCoulomb of 19.3 MeV electrons hitting 1.18 mm of Ta produces X-rays which illuminate a 0.8 mm thick by 1.6 cm diameter Cu disk placed 46 cm from the Ta. The activated Cu is placed in a counting system with a window between 400-600 keV and produces about 42500 counts in the first 100 sec counting period. Less than 0.2% of the initial activity is due to other reactions. Photo-induced neutrons in Be parts of the system are shown to produce a negligible effect in the Cu. The main disadvantage of the Cu activation is its sensitivity to electron energy. Monte-Carlo calculations of the excitation function for our accelerator are shown, along with excitation functions for three other configurations.

The present study is directed towards quantifying some of the parameters which define the quality of the image obtained on x-ray sensitive films and its usual accompanying intensifying screens. Both industrial (AgfaGeveart D2,D4,D7) and medical (Kodak XAR-5) films with a variety of screens such as metallic (lead) and fluorescent (calcium tungstate, rare earth) were compared. A variety of sources were employed (radioactive, linear accelerators, flash) in order to cover the average x-ray energy spectrum from 100KeV to 3000KeV. This energy spectrum is of interest for non destructive testing, terminal ballistics and for medical purposes.

Repetitive gating of an invertor-type image tube has been achieved by a new technique involving the use of two grid electrodes. The method makes it possible to use gating pulses of imperfect shape without severe loss of image quality.

High speed gating with exposure times below 1 ns requires specially modified image intensifier tubes. This contribution deals with such a tube incorporating a dual microchannel plate (ITT F4144 mod.). In connection with a SIT-camera, single photoelectrons can be detected. For gating the tube, special avalanche circuits were developed with pulse width as small as 200 ps (FWHM). The deterioration of the gating pulse by lead inductance and tube capacitance and the attenuation caused by the surface resistance have to be regarded to evaluate the exposure time. As at least the surface resistance of the gating electrodes is unknown, direct measurements are inevitable.

High-speed photography of human motion requires high levels of lighting. Distributed lights are preferred. A medium focal length lens is used to minimize distortion. Coloured markers are used to define land marks on the body. The practical considerations involving the choice of equipment are discussed.

Over many years, the high voltage gas discharge studies undertaken by the Electrical Power Engineering Group in the University of Strathclyde, Glasgow have benefitted from the use of ultra-high-speed photography. The use of image-converter-intensifier cameras, with a maximum framing speed of 2x10⁷s^-1 and a maximum streak-speed of 1000mm/us is described. The various techniques used; the problems encountered and a brief selection of recordings obtained are presented.

This photography involves applications in the millisecond to microsecond region. A good focusable camera is aimed at the object to be filmed. Upon operating the camera shutter, the shutter opens and the camera's flash contacts close. A special high current (approximately 1000A) pulse controller is activated which pulses a circuit breaker sample (or assembly) with exposed (or can be viewed through clear plastic) moving parts. At the same instant (i.e. commencement of the pulse) the first flash gun is fired and thereafter the remaining flash guns (5 total ) sequentially. Control of these flash guns is by means of a special custom built controller. The photograph will show the "moving object in several fixed positions". A variety of information can be calculated from this photograph.

The technique of moire-enlargement can be used to construct a new 360°-display which shows pictures without foreshortening from all sides. We show that this cycloramic display is suitable for a movie camera which could be accelerated to speeds comparable with those of known raster cameras.

During nucleate boiling thin liquid films (nicrolayers) form beneath the base of bubbles and evaporate into the bubble interiors. A technique is presented which permits the simultaneous determination of microlayer topology and the contribution of microlayer evaporation to bubble growth. Isolated-bubble boiling takes place on an electrically heated, transparent tin-oxide coating deposited on a glass plate, the latter forming the floor of a vessel. With coherent Claser) illumination from beneath, the microlayers reflect fringe patterns similar to Newton's rings. Owing to the rapid evaporation of the layers (the process is completed within milliseconds) the fringes are in rapid motion and are recorded by eine photography at some 4 000 frames per second and exposure times of 50 μs. The resulting interferograms provide details of microlayer shape and thickness versus time, and thus evaporation rate. Simultaneously, and on the same film, bubble profiles (and thus volumes) are obtained under white light illumination. The two bubble images are manipulated by mirrors and lenses so as to appear side by side on the same frame of film, the fringes magnified and the profiles reduced. Sample results for methanol boiling at a pressure of 58.5 kPa and with the liquid bulk at saturation temperature, are presented. Under such conditions microlayer evaporation accounts for 37 per cent of the total bubble volume at detachment.

This paper describes a technique which measures the deflection-time history of a structure subjected to an explosive load. Photo voltaic diodes are used to measure the light interference patterns obtained during deformation. Deflections of up to 20 mm over a time period of 200 μs have been observed.

Several fast, single transient data imaging systems have been developed for time-resolved imaging of pulsed radiation sources. Both MCP intensified solid-state, two-dimensional framing cameras and streak cameras/solid-state camera systems are used.** The streak camera system yields small, two-dimensional images with limited spatial resolution (< 150 spatial points) and ≤ 0.5 nsec exposure. It is those streak camera systems developed at Lawrence Livermore National Laboratory that are used for obtaining time-resolved, tomographically reconstructed, two-dimensional images of electron and x-ray beams.

High speed camera coorperated with laser trigger to catch high speed unpredictable events has many applications: such as scoring system for the end game of missile interception, war head explosive study etc. When the event happening in a very short duration, the repetition rate of the laser ranging must be as high as 5K herze and the pulse duration should be less than 10 nsec. In some environment, like inside the aircraft, the abailable space for high speed camera to set up is limited, large film capacity camera could not be used. In order to use the small capacity film, the exact trigger time for the camera are especially important. The target velocity, camera acceleration characteristics, speed regulation, camera size, weight and the ruggedness are all be considered before the laser trigger be designed. Electric temporal gate is used to measure the time of flight ranging datum. The triangular distance measurement principle are also used to get the ranging when the base line i.e. the distance between the laser transmitter and receiver are large enough.

This paper describes the basic technique of schlieren photography in simple terms and then goes on to discuss the latest trends and developments in schlieren systems. There is some discussion of the use of schlieren photography for non-scientific applications.

The paper presents a feasibility study of obtaining reliable space measurements of dimension on a small object, from the three-dimensional virtual image of the object's hologram. Associated with the main objective of this paper as described above, detailed information is presented on the actual technique of obtaining a hologram, the type of holographic film used, exposure tines, and developing and bleaching procedures. Using the transmission holographic technique, good quality holograms of small objects were obtained. These holograms, when viewed in a reconstructed reference beam set-up, produced a good quality virtual or orthoscopic image. In a set-up involving the holographic reference beam, reproduced around a reflex metrograph, orthogonal co-ordinates of various points on the virtual image were obtained. Four sets of measurements were obtained, averaged and the results were compared with a set of measurements obtained from the actual object when using a reflex microscope. By rotating the axis frames of the two instruments into a common reference axis set, direct comparison of the co-ordinates and dimensions of the object, obtained by the two methods, was effected. Since the maximum error obtained in the comparison of any co-ordinate was of the order of 1.0%, it was concluded that mensuration of dimensions from the virtual holographic image of an object is possible.

The micro computer expert system for high-speed photographic system has been built up. It include a body of specialized knowledge base and problem solving mechanism such as equation solver etc. about high speed photography such as, the object analysis, cameras installation, operation, lighting, etc. and makes that knowledge conveniently available to user working in high-speed photographic system planning. Backtracking involves replanning from the choice point of failure. The data base are build up from the camera manuals including the framing rate, lens focal length, film capacity, shuttering characteristics camera size, weight and ease of operation etc. The possibility of interfacing to the real world to monitor the progress of operation as well as to feedback the state of world are all discussed.

We have developed a technique for measuring size distributions of particles in the 1 to l0μm range that are moving at speeds of up to 4mm/μsec transverse to the direction of observation. We do this by measuring intensity as a function of angle for light scattered from the particles using an electronic streaking camera to record variations in time. Initial experiments studying particles ejected from shocked lead surfaces indicate that there are two dominant size classes having diameters of approximately lμm and 6μm.

High speed TV cameras that incorporate modified seeker section of IR-homing missile to indicate exactly where the seeker is aimming, have been built up to identifying the aimming point of the specific IR target. The high speed TV cameras is used, to record the field of view & target. Error signals from the seeker are transfered to a cross signal and then to a video monitor. The overlapping of the target image with the cross hair signal indicate where the seeker is looking. The time mark are indicated on the frame record by digital number and alphabet in the upper right coner of the frame. Instead of high speed TV camera, the thermal vision image camera could also be used in the aiming point and the infared signature study. The thermal vision image camera has lower frame rate and could not look at fast variant target.

Progressive Lightning is a most suitable heading for the specific studies that these scientists made. First because it is the title under which all of them wrote at some time or other; second because their studies were truly progressive in advancing knowledge; and third because the dictionary describes "progressive" as "step by step advancement" reminding us of the "step" nature that their photographs showed of lightning channels progressing.

The variety, range and precision of methods available for photographic recording of fast phenomena have been increasing steadily. The capabilities of the techniques are considered, classifying the methods by the kind of record obtained. descriptions of experimental techniques and apparatus, and illustrations, are given in earlier articles: "A Review of the Methods of High-Speed Photography," Reports on Progress in Physics in 1957; "Advances in High-Speed Photography 1957-1972," Proceedings of the Tenth International Congress on High-Speed Photography and also JSMPTE 82, pp. 167-175 (1973); "Advances in High-Speed Photograph, updated to 1983 in the Proceedings of SPIE Volume 427.

Ladies and gentlemen, it is indeed a great privilege and pleasure for me to present the opening address at this, the 17th International Congress on High Speed Photograpy and Photonics. Before turning to the business of the Congress, I would like to briefly introduce you to South Africa: its scientific past and its research challenges for the future.

High speed photography is being employed to help improve the efficiency of a number of different mining activities. Its principal use, however, is as an aid in the optimization of blasting operations. Blasts are commonly of very short duration and great benefit can thus be gained by being able to observe the events at a suitably selected slow motion over an extended period of time. This paper presents an overview of some of the high speed photographic applications in both surface and underground operations using qualitative and quantitative techniques. The primary use is the direct photography of the blast, the analysis of the resulting films representing the bulk of the optimization work. Other applications are designed to check out individual blast components, particularly evaluating blast tamping, and actual delay element times for such accessories as detonating relays, down-the-hole delays and other delaying and initiating systems.

Over the past 40 to 50 years numerous theories of rock breakage by explosives have evolved. These theories can be divided into two general categories depending on the relative importance ascribed to fracturing caused by gas expansion and stress wave energy sources. A major obstacle in the study of explosive rock breakage mechanisms is separation of affects from these two energy sources. A technique is under development which restricts by means of a blasthole liner, the penetration of explosive gas products into the rock mass surrounding the charge. Thus the character of stress waves developed in the rock is virtually identical to an unlined hole while the breaking action due to gas expansion is severely curtailed. This paper summarizes preliminary results from initial experiments using this technique to study the rock breakage mechanisms operative in gold mine stope blasting. Each experiment incorporated high speed photography and other instrumentation to observe and record the burden rock response to contrasting explosive loading conditions.

In recent years high speed photography (hsp) has become an essential tool for evaluating surface blasting phenomena. Hsp is indispensable for capturing the short lived events, often of millisecond duration, typical of any blast. The resulting time base allows quantitive and qualitative studies to be made. Qualitative information can be used immediately to achieve improved blasting results. Problems can be pinpointed or problem areas identified for future investigation. Applications range from blast trouble shooting to blast design and product evaluation. Different explosive types and accessories are simply and quickly evaluated. The advantages and disadvantages of one product over another are highlighted and the necessity for ongoing product trials may be diminished. Routine blast monitoring may then be carried out to ensure that the product continues to perform efficiently. This paper looks at a number of surface blasts ranging from the ideal to the non ideal and discusses the type of information that has been obtained from high speed films.

Premature initiation of ANFO (an explosive mixture of Ammonium Nitrate and Fuel Oil) at a large colliery, near Witbank, was first detected from routine high speed films taken of large mid-burden, and overburden blasts. The analysis of these films shows that the rapid migration of very hot gasses through cracks ahead of the blast may have caused the explosive to initiate prematurely. The problem was not seen in the less competent overburden rocks. A less sensitive explosive has been successfully tried. The assessment of these blasts using high speed photography is discussed.

During the short duration of an explosive blast, many events occur which are too quick to be detected or observed in detail with the naked eye or by normal photographic techniques. Through the use of "hightech", high speed video, many of these events can be observed, instantly played back and recorded for later use. The use of a Spin Physics SP 2000 Motion Analysis System at a blast casting operation is presented. The system was used for a variety of tasks including, but not limited to the determination of delay accuracy to within 0.5 ms, the velocity and trajectory of the faces during blasts and pinpointing geological problem areas.

Streak technique signifies stretching out in terms of time a process under observation. Originally, the event under observation was imaged via the main lens to the slit of the streak camera. Only the image of a narrow strip of the event which passes through this slit is shown via the camera lens and the rotating mirror on the film plane. On rotation of the mirror, a chronological event is retained, spatially stretched, on the film according to the speed of the camera.

The interaction between water and explosives in an air environment has been studied. Some interesting properties observed with high speed and normal photography were put to work. Both the mass and latent heat of water played an important role.

It is well known that a detonation wave progresses through a cylindrical explosive medium in concentric circles with a constant velocity in all directions providing that the diameter of the charge equals or exceeds the ideal diameter.

Although the lens provides the link between the high speed camera and the outside world, there has over the years been little evidence of co-operation between the optical design and high speed photography communities. It is still only too common for a manufacturer to develop a camera of improved performance and resolution and then to combine this with a standard camera lens. These lenses were often designed for a completely different recording medium and, more often than not, their use results in avoidable degradation of the overall system performance. There is a tendency to assume that a specialized lens would be too expensive and that pushing the aperture automatically implies more complex optical systems. In the present paper some recent South African developments in the design of large aperture lenses are described. The application of a new design principle, based on the work earlier this century of Bernhard Schmidt, shows that ultra-fast lenses need not be overly complex and a basic four-element lens configuration can be adapted to a wide variety of applications.

This review is restricted to the historical development and the present facilities at the NPRL for the design and evaluation of axially symmetric imaging electron optics. The basic mathematical problem is briefly defined. The numerical method applied and developed to solve the mathematical problem for real axially symmetric devices and their characteristics is summarized. The computer facilities that have been used since 1970 for the development and operation of the electron optics software are reviewed. The capabilities and efficiency of the present software and hardware systems are discussed in some detail. To enable evaluation of the quality of the electron optics of experimental imaging devices, an experimental electron optics bench and ancillary equipment for image quality assessment were also established. These experi-mental aids are also briefly described.

The purpose of this project was to develop systems for generating kinematic data on human movement and shape. We based our designs around the MicronEye digital camera, a device costing less than $300 which interfaces directly to most personal computers. To measure movement we have developed the Motion Monitor, and for shape our device is called the TopoScanner. These two instruments have three common features: they are remote, inexpensive, and generate the kinematic data automatically within a few minutes. They have been used for a wide range of biomechanical studies, including the crawling patterns of cerebral palsied children pre-and post-operatively, and the shape of rheumatoid patients' feet.

The National Aeronautics and Space Administration (NASA) utilizes many different types of photographic instrumentation systems and motion picture cameras for recording the events that take place in support of the United States Space Programs. There are many special camera systems, used both on board the Space Shuttle and for extra vehicular activity, which are located in the crew compartment areas, shuttle cargo bay and thermal enclosure, etc. This equipment can either be operated manually or can be remotely controlled. The cameras are used for numerous purposes, including crew operations and experiments, debris analysis, payload data recording, earth viewing, CRT test and graphics recording and other documentation.

To investigate the motion of very fast droplets in gas the method of high speed cinematography is particularly qualified. The problems are that very short exposure times and high framing rates are necessary. Therefore a special experimental set up was developed and the injection of fuel was investigated with this apparatus. The results are demonstrated by special examples.

Refractive fringes, were first observed by Evtushenko (1) et al. They are defined as intereference fringes caused by the interference of light refracted by an object either with other light refracted by the same object or with light that avoided the object by a small distance.

The parameters governing the design of a streak camera based on the Photochron IIC streak tube and using a charge-coupled device as readout is described. The camera is intended to form part of a spaceborne system used to measure the roundtrip times of laser pulses, directed from a satellite to ground-based retroreflectors, so that range can be computed with millimetre accuracy. The possible future use of a custom built circular CCD/diode array, mounted within the vacuum envelope of the tube, is discussed.

Holography has been used to record high speed events for the past 20 years. The events include particle and projective impacts, particle dispersion, and a variety of flow field configurations of interest in aerodynamics. Most of these studies and the ones discussed in this article, use either ruby lasers or neodymium YAG lasers, with pulse durations of 10 to 20 nanoseconds. Holography is important for particle dispersion studies because the particle locations, shapes and velocities can be examined three dimensionally after the event has passed. Examples occur in the examination of fuel spray jets and liquid droplet breakup. Holography is ideal for the study of flows in wind tunnels because of its ability to capture the phase of the coherent light transmitted through these fields. Several rather elaborate holographic interferometer methods have been implemented including double pulse, finite fringe, and phase cancellation. Two recent and ongoing programs which also use hologram interferometry are of special interest. The first of these is a study of the imaging capabilities through the turbulent boundary layers which exist over optical windows in high speed aircraft. Recent findings show that some corrections for this turbulence are possible. The second program deals with the analysis of the three dimensional flow field about a rotating helicopter blade. It is interesting because it combines holographic flow field analysis with computed tomography.

One of the less obvious and visible features which distinguishes South Africa from the industrialised countries of the northern hemisphere is its heavy use of synthetic liquid fuels for road transport. Nearly 40% of our liquid fuel requirements are produced synthetically from coal. With the discovery of wet natural gas off the coast of the Southern Cape Province there are plans to increase synthetic liquid fuel production.

Preliminary results are given of the use of schlieren techniques for the analysis of dimples produced by water surface organisms such as water skaters. Since the schlieren technique is particularly sensitive to the refractive gradations of the dimple it is believed that it is more sensitive than other existing techniques for this type of study.

X-ray streak cameras are a major diagnostic in the study of laser-produced plasmas (LPP's) and laser-driven inertial confinement fusion (ICF). Using highly sensitive cesium iodide photo-cathodes they have a temporal resolution of tens of picoseconds and a spatial resolution of tens of micrometers in the image plane. A brief introduction to the physics of LPP's and ICF is followed here by two applications, viz, implosion dynamics and time-resolved spectroscopy.

High speed cine photography is a useful diagnostic aid for studying plasma behaviour and plasma surface interactions in fusion research devices like tokamaks. Such a system has been installed on the AEC tokamak. This paper reports some preliminary results obtained during typical plasma discharges.

High speed cind photography has been used extensively in combustion research work carried out in the Mechanical Engineering Department at Leeds University. The experimental techniques adopted are presented and discussed, in particular, experiments that have been conducted on 'Turbulence and Combustion Rate in Homogeneous Charge Spark Ignition Engines'. Analysis of the 16 mm cine film enabled the flame progress to be charted when photographed through a modified perspex cylinder head. Comparison is made between single and dual, or divided, chamber cylinder heads. The cylinder head geometry is changed by using different pre-chamber sizes to vary the volume ratio and the interconnecting orifice size is also varied. The dual chamber engine is suggested to be a useful vehicle for genera-ting fundamental data, of a general nature, for turbulent burning rate in an S.I. engine and for validating mathematical models of such engines.

The application of CCD-TV-cameras to high speed techniques is presently limited by the speed of the serial signal read out. Many CCD-Sensors are constructed using the frame transfer technique. Then it is possible to take two pictures within a time interval of about 400 μs. The electronical storage of a picture on the CCD make other applications possible. On is the use of stroboscopic illumination. Another possibility is the electronical Cranz-Schardin-Camera. The third application described in this paper is a CCD streak camera. In this camera the exposure is necessary during the fast frame transfer from the lightsensing area to the memory of the device. The time resolution was 1.6 μs with standard driver circuits and can be faster with high current shift pulses. Furthermore, a reduction of the frame size makes high speed sequences possible.

A low cost, high speed video system based on a standard TV camera using a low lag pick-up tube such as the Plumbicon is described. The modifications required are basically of an opto-mechanical nature and the additional electronics is minimal. No modifications to the existing camera electronics are necessary.

The resolving power characteristics of three contemporary high-speed imaging systems were evaluated under nearly identical test conditions. In generic terms, the image-recording sensors evaluated in this study consisted of 1) a high-speed 16mm color film, 2) a high-speed monochrome and color video, and 3) a monochrome solid-state CCD sensor. The commercially available cameras embodying these sensors were 1) the Locam 16mm high-speed intermittent camera, 2) the NAC HSV-200 high-speed video camera, and 3) the Spin Physics SP-2000 and Ektapro 1000 cameras. Resolving powers at three target contrast levels were determined using the same objective lens on each camera system with the same aperture setting. Spatial resolutions for all three systems are expressed in terms of total information bits per frame. This resolution metric for 16mm color film exceeds those of the other image sensors by a factor of 2:1 for low-contrast subjects and over 5:1 for high-contrast subjects.