Camera Manufacturers Research Articles

Three-dimensional geometric sensitivity calculation for three-headed coincidence imaging

All major gamma camera manufacturers nowadays offer two-headed coincidence imaging with their gamma camera systems. To improve sensitivity, three-headed coincidence imaging has been proposed. In an earlier work, the authors investigated how the two-dimensional sensitivity varies in the field of view of such a system. Here, these calculations are extended to three dimensions, taking into account the finite axial length of the detector. The extension to three dimensions becomes particularly important when one acquires data in fully three-dimensional mode, without using axial septa. The three-dimensional sensitivity calculation presented here is valid for any position of the camera, such as a U-shaped configuration or a triangular configuration. The authors have also investigated the use of axial septa by constraining the maximum axial incidence angle.

New slip rings offer flexibility for CCTV and dome camera manufacturers

New slip rings offer flexibility for CCTV and dome camera manufacturers

Software planning of assembly lines

The article introduces eM‐Assembly, one of the new generic computer aided production engineering solutions from Tecnomatix. The solution incorporates a number of modules to plan, optimise and apply discrete event simulation to the layout and sequence of assembly lines. The physical mating of parts may be continuously simulated in another module and any collisions detected. The use of the eM‐Plant module to assist a Japanese camera manufacturer in planning a new assembly line is discussed and the benefits achieved in improving throughput and saving on capital highlighted. Brief details are also given of achievements by two other users.

The integration of digital camera derived images with a computer based diabetes register for use in retinal screening

Exeter district provides a retinal screening service based on a mobile non-mydriatic camera operated by a dedicated retinal screener visiting general practices on a 2-yearly cycle. Digital attachments to eye cameras can now provide a cost effective alternative to the use of film in population based eye screening programmes. Whilst the manufacturers of digital cameras provide a database for the storage of pictures, the images do not as yet interface readily with the rest of the patient's computer held data or allow for a sophisticated grading, reporting and administration system. The system described is a development of the Exeter diabetes register (EXSYST) which can import digitally derived pictures from either Ris–Lite TM and Imagenet TM camera systems or scanned Polaroids Pictures can be reported by the screener, checked by a consultant ophthalmologist via the hospital network, and a report, consisting of colour pictures, map of relevant pathology and referral recommendations produced. This concise report can be hard copied inexpensively on a high resolution ink-jet printer to be returned to the patient's general practitioner. Eye images remain available within the hospital diabetes centre computer network to facilitate shared care. This integrated system would form an ideal platform for the addition of computer based pathology recognition and total paperless transmission when suitable links to GP surgeries become available.

Computer aided measurement and compensation system for focal length of lenses in camera manufacture based on the MTF performance using the line CCD sensor

A computer aided system has been developed for the focal length measurement/compensation in camera manufacture. Signal data proportional to light intensity are obtained and sampled very rapidly from the line CCD. Based on the measured signal, the MTF performance is calculated, where the MTF is the ratio of magnitude of the output image to the input image. In order to find the optimum MTF performance, an efficient algorithm has been implemented using the least squares technique. The developed system has been applied to a practical camera manufacturing process, and demonstrated high productivity with high precision

ON THE RECOVERY OF MOTION AND STRUCTURE WHEN CAMERAS ARE NOT CALIBRATED

This paper addresses the problem of computing the camera motion and the Euclidean 3D structure of an observed scene using uncalibrated images. Given at least two images with pixel correspondences, the motion of the camera (translation and rotation) and the 3D structure of the scene are calculated simultaneously. We do not assume the knowledge of the intrinsic parameters of the camera. However, an approximation of these parameters is required. Such an approximation is all the time available, either from the camera manufacturer's data or from former experiments. Classical methods based on the essential matrix are highly sensitive to image noise. This sensitivity is amplified when the intrinsic parameters of the cameras contain errors. To overcome such instability, we propose here a method where a particular choice of a 3D Euclidean coordinate system with a different parameterization of the motion/structure problem allowed us to reduce significantly the total number of unknowns. In addition, the simultaneous calculation of the camera motion and the 3D structure has made the computation of the motion and structure less sensitive to the errors in the values of the intrinsic parameters of the camera. All steps of our method are linear. However, a final nonlinear optimal step might be added to improve the accuracy of the results and to allow the orthogonality of the rotation matrix to be taken into account. Experiments with real images validated our method and showed that a good quality motion/structure can be recovered from a pair of uncalibrated images. Intensive experiments with simulated images have shown the relationship between the errors on the intrinsic parameters and the accuracy of the recovered 3D structure.

Ophthalmic Photography: A Textbook of Retinal Photography, Angiography, and Electronic Imaging

Saine and Tyler have assembled a book that may be the most comprehensive textbook on ophthalmic photography; it is certainly the most up to date regarding electronic imaging of the fundus. It is creatively illustrated and contains several hundred images, both color and black and white. The book is divided into 9 main chapters, each with a title page containing an outline of the topics to be discussed. Many chapters make use of sidebars, shaded boxes containing helpful hints and practical suggestions. They provide additional detail to the text with, for example, tips for dilating the difficult patient and suggestions for determining the correct film exposure for young children. Three appendixes provide a list of helpful abbreviations used in ophthalmic photography, a list of professional societies and companies of general interest to the photographer, including manufacturers of stereo equipment, digital cameras, and software useful in ophthalmic photography. A comprehensive index

Clive Lister (1936–1995)

Clive Lister was born in Uxbridge, England, on February 8, 1936, to parents who had moved from Germany to England to establish a camera manufacturing business. Subsequently they realized how fortunate they were to have escaped from the horrors of the rise of Nazism. He went to St. Paul's School in Hammersmith and, after a spell of national service as a gunner in the British Army Air Corps, he attended Trinity College, Cambridge, on a senior scholarship. Clive entered Cambridge in 1956, received a B.A. in physics in 1959, and a Ph.D. in geophysics in 1962. After a short postdoctoral fellowship in La Spezia, Italy, and 2 years of working in industry for Willard Bascomb in the United States, he joined the faculties of the Geophysics Group and the Department of Oceanography at the University of Washington, Seattle, in 1965. There he remained until he took early retirement in 1990. Clive died of a massive heart attack at his home in Darrington, Wash., on August, 4 1995. He was 59 years old.

An unconventional plate-changing system

Abstract Starting well before the introduction of roll film, and continuing for over a decade after this medium became readily available, manufacturers of dry-plate cameras worked on simplifying the plate-changing procedures. In the search for better methods, they came up with a variety of unusual designs,1 including that of the Quad Camera.2 The 1896 Montgomery Ward & Co., Chicago, photography catalogue3 describes the Quad as ‘a compact, inexpensive camera ... 4⅝ × 4⅝ × 6 in., fitted with quadruplex undetachable plate-holder, achromatic lens, view-finder and shutter for either time or instantaneous exposures’. The ‘quadruplex’ plate-holder refers to four single plate-holders, each of which is hinged at the (opening) rear-end of the camera and stores parallel to the inside ‘wall’, to which it is attached. Since the plates must be loaded in darkness, and since most buyers of the Quad did not have darkrooms, the manufacturer offered a changing bag as an optional accessory. Its use was covered by the instructions.

Popular Photography, Scenery Values, and Visual Assessment

Abstract Early twentieth-century amateur photography helped shape contemporary notions of beautiful rural scenery. Photography magazines counseled the American public to choose specific sorts of landscapes in which to make pictures; their detailed instructions combined with camera manufacturer advice to create an aesthetic emphasizing such spatial features as free-standing trees, open middle distances, and herds of cows while banning utility poles and other industrial items. Gradually, beautiful rural scenery came to be identified with particular sorts of views accessible from motor cars.

Thallium-201 imaging artifacts not detected by technetium-99m or cobalt-57 quality-control testing.

Early stages of hydration in a sodium iodide crystal may cause artifactual "hot" spots on thallium-201 heart images. This phenomenon was observed when a mobile gamma camera was used even though the daily quality-control flood-field views revealed no apparent abnormalities. Nevertheless, hot spots were visible on thallium-201 and xenon-133 flood-field images. With asymmetric photopeak positioning using a technetium-99m source, hot spots were noted in addition to phototube nonuniformities. Subsequently, the camera head was disassembled, the crystal was inspected visually, and the crystal seal was found to be broken. Hydration of the crystal was confirmed by the camera manufacturer. Quality-control procedures should test for hydration-induced artifacts on a regular basis.

A Comparison of Retinal, Fundus Cameras: Users Survey Results

The purpose of this paper is to present the different models of fundus cameras available on the current market. Included is a users survey for which 775 questionnaires were sent to ophthalmic photographers for evaluation of their equipment. A total of 394 questionnaires were returned. Possible bias in the users survey was decreased by excluding eight of the returned questionnaires that indicated proprietary interests. Thirty-two photographers reported that they used two or more camera systems. The survey results do not include all of the cameras that are currently available; only the camera models for which evaluations were returned.Some of the returned questionnaires listed cost as one of the best or worst features of a particular system. However, this survey reflects only the technical data supplied by the users, as cost may not reflect the quality of a system. The authors have taken into consideration the fact that the manufacturers of fundus cameras are continuously striving to update their products and realize that upon publication of this article newer models may be available. The authors wish to note that neither has any proprietary interest in the development or marketing of any fundus camera system and to be as objective as possible, they did not contribute to the technical data.

Des Lip nippons

There are several different ways in which Japanese enterprises that are forced to declare bankruptcy become self-managing : either upon prompting by the trade-union, as in the case of Van, a wholesale textile dealer or of Petri, a camera manufacturer, or by the workers joining a trade-union which launches the process of self-production as in the case of Paramount, a ladies’ shoe manufacturer. The problems vary from one company to another : production, turnover of products, market hostility, the level of salaries, workers’ participation in management, the need for specialised management are all factors which continually challenge the functioning of the enterprise in self-management.

Modulation Measurement Applied to the Focusing of Aerial Cameras

Photoelectric measurement of aerial image modulation at a single spatial frequency has been applied to the focusing of lenses in aerial cameras. Using an automated apparatus to provide a plot of modulation through focus, the settings are made in a fraction of the time and with much greater confidence than by the photographic resolving power method. It is pointed out that the focus for a single well-chosen frequency can be a good index of the focus for all frequencies in the photographically-important region of the MTF of the lens, also that a through-focus plot of modulation at one or two important frequencies is often of greater value to the camera manufacturer than the usual MTF plot at one focus position. The well-known difficulty in focusing some lenses by high contrast resolving power is explained in terms of their decreased sensitivity to focus setting above a certain frequency; in some cases this effect cannot be eliminated by moderate stopping down. Although primarily designed for measuring relative modulation on axis, the apparatus can be calibrated to read absolute modulation to a useful degree of accuracy, can be used off-axis, and has many photo-optical applications.

Patent Statistics as a Measure of Technical Change

This paper examines a question of long standing: How can one obtain operational indexes of inventive and innovative activity and technical change? Specifically, for a sample of fifty-seven pharmaceutical manufacturing firms, we attempt to determine how well a simple count of invention patents serves as a surrogate for two alternative measures of technical change: the number of research and development personnel employed, reflecting inputs into the innovative process, and the value of new product sales, which reflects outputs of the process.

The Location of Camera Industry In Japan

The writer has investigated the distribution of camera manufacturing Industry, and inquired the geographical significance of its location in Japan. The following have been disclosed.1. About 65% of camera production comes from Tokyo metropolis, the main part of Keihin industrial area, furthermore; 70% of its workshops are also concentrated in Tokyo, forming the core of distribution in Japan.2. In Tokyo area, some 60% of the workshops are in Jonan district (Ota, Shinagawa, Meguro etc) southern parts of Tokyo, which is the core area of the Keihin industrial belt. And about 30% of the works are provided in the Johoku districts (Itabashi, Toshima etc), northern parts of Tokyo, being a nucleus district of binoculars production.3. About 2, 000 kinds of parts are required to manufacture any kind of camera. Such being the case, most parts of camera are supplied from subcontact parts-makers operated on a small scale. For the convenience of concentration most of them are located in the neighborhood of the camera makers to keep production at low cost.

Picture Jump and Weave in Rotating-Prism Cameras

More unsteadiness is experienced in pictures exposed in rotating-prism high-speed cameras than in pictures exposed in intermittent movement cameras. Film dimension standards are based on conventional motion-picture experience and films perforated over the range permitted exceed tolerable limits for high-speed work. Progress to date has been based on a cooperative effort between camera and film manufacturers but has not yet advanced to the establishment of standards for this more critical film usage. Dimensional instability of photographic materials has compounded the problem. Camera motive power, design of sprockets and spools, and “greenness” of film are also cited as factors contributing to unsteadiness.

ECONOMIC PLANNING IN JAPAN

The reco~ery and growth of the Japanese economy after the destruction o~ World War 11 have been rem~rkable. The volume of industrial production, which had been reduced to only one-third of prewar level, re~ained the 1934-36 Ievel as early as in 1951, and in 1962 it was flve times as high. Today the Japanese economy is approaching the level of some of the West Eurdpean countries, both in scale of production and in the living standard of the people. Japan is now the fifth biggest industrial producer in the world, following the U.S., U.S.S.R., U.K., and West Germany. In respect to several industries such as shipbuilding, transistors, T.V. sets, and camera manufacturing, she is the biggest producer in the world. National income per head of population in 1961 was just over $ 400, only twenty per cent lower than that of Itaiy, although it is a long way to reach the level of the U.K. or West Germany where it is around $ 1,000. With such growth of production and improvements in living, Japan is now accepted as one of the advanced nations i~l the international community. In the summer of 1963, she joined the Organization for Economic Cooperation and Development. This is the first time a country outside North America and Western Europe was admitted to membership in the organization of advanced n.ations. It was already decided that Ja~an would be transferred to the Article 8 status in the IMF Agreement. In August 1963, her ratio of import liberalization reached 92 per cent, which is comparable with most West European countries. Needless to say, a number of factors have been responsible for the remarkable achievements of the Japanese economy. Since these factors have been already analysed by competent economists, I shall confine myself here to mentioning only two features pertinent to the subject of this paper.l One of them is the very positive attitude of Japanese business firms under the competitive market system. They are confident of the future growth of the national economy, eager to adopt the latest techniques, and enthusiastic to expand their own business activities in spite of severe competition at home and abroad. For instance. Japa~rese businessmen imported and utilized advanced foreign technology to the fullest extent possible. Tremendous amounts of resources have been invested in the most modern equipment, with a resultant rapid rise in productivity and increased competitiveness in