- Email: [email protected]
Laser scanning components and techniques
getting out of date during the writing. This pitfall has been avoided however and the references include much work published in 1975. One topic which probably will need up-dating (in the next edition?) is that of unstable resonators. This receives only the briefest mention but work bver the last year suggests that they will have an important role to play in solid-state laser systems. All in all however this is an excellent book and for anyone concerned with solid-state lasers, it will be a valuable addition to their library. D.C. Hanna
Low light level devices for science and technology Edited by C. Freeman
Arizona to replace photographic film by video tape. At the latter university they are particularly concerned with the resolution limitation of currently available video systems and report on investigations with a high resolution system. It is some years since thermography was hailed as the certain answer to the early diagnosis of breast cancer. Following the early euphoria a greater sense of realism has prevailed, and more cautious attempts to correlate temperature variations in the human body with their underlying causes is being studied on a more quantitative basis. Some preliminary findings are reported. Of course most of the advanced equipment in the infra-red field has a military significance and for these reasons is excluded. Nevertheless this omission should not be allowed to detract from the value and interest of these proceedings. A. IV. Woodhead
Proceedings of the Society of Photo-Optical Instrumentation Engineers, Volume 78, 1976, pp 162, $36.00 This conference, which was held from 22-23 March 1976 in Reston, Virginia, brought together the whole spectrum of workers in the field of electronic image formation, from those investigating the newest devices to the astronomers, doctors and others who ultimately judge the value of the end-products by the value of the pictures which are produced. There were four sessions, the first of which attempted to bring up to date the published information on a number of imaging devices which operate in the visible and infra-red spectral range. The remaining sessions were devoted to a variety of applications but with particular emphasis on astronomy and medicine. Like all miscellaneous collections of conference papers the standard varies. Indeed some papers appear to have been included for the sake of completeness as they have little or nothing new to say. However, workers in the field will find this a very useful cross-section survey of progress in some of the main areas, while the general reader wilI also find much of interest. Predictably we find the vacuum tube intensifier being pressed by the solid-state charge-coupled and charge-injection devices, A number of papers attempt to establish the potential of these devices at very low light levels by following, sometimes rather slavishly, the simplified analysis technique developed for intensifier and camera tubes. They predict performance thresholds which equal or surpass those of present day vacuum tubes. However, there seems to be some way to go before the solid-state devices can match broadcast camera tubes in picture quality and content. It is for these reasons that most of the applications of CCDs and intensified CCDs are reported in the session devoted to astronomy.
Laser scanning components and techniques Edited by L. Beiser, G. F. Marshall
Proceedings of the Society of Photo-Optical Instrumentation Engineers, Volume 84,1977, pp 147, $36.00 The papers given at a two-day symposium held in San Diego on 24 and 25 August 1976 are presented. The field covered is concentrated on design considerations and trends in the instrumentation of devices for information-handling systems, and will be of most interest to development engineers involved in the field or in related subjects. It will also be useful to the managers, planners, and market study experts involved with this potentially very profitable area of technology. There is some derivation from earlier SPIE seminars, especially the seminar on ‘Laser recording and information handling technology’ published as Volume 53 of SPIE proceedings, which included one session on scanning and modulation. The present volume indicates how much has developed in the USA in the two-year interval, and deals with aspects of scanning technology in detail.
A few years ago there was a tendency to write-off the pyroelectric vidicon on the grounds of poor resolution and inadequate sensitivity. In this field in particular persistance seems to be bringing its rewards. Improvements already introduced, or which are now in the pipeline, could result in this tube finding a variety of uses where a good performance ( < 0.8OC minimum resolvable temperature difference at 400 tv line resolution) at moderate cost is required.
The nineteen papers are well matched and very readable. Considerations of the same field by several different authors provides an informative comparison between the specialities of competing companies. The basic common ground is the better understood for the reinforcement, in spite of apparently unnecessary duplication, but the parallel studies become most useful in extending the range of variation in applications. As might be expected, pride of place is given to a serious market potential study. For the period up to 1980 it is forecast that the information handling field will be increasingly profitable in the USA. Optical character readers, computer memories, and laser recorders will require the instrumentation now described as essential contributions to the value of the turnover estimated at something like a billion dollars.
The pressure to reduce dose rate whilst still providing the maximum amount of useful diagnostic information has long made x-ray imaging a fruitful field for the application of the techniques which were the subject of this conference. Now the cost and the space required to keep the records are stimulating attempts at the Universities of Pittsburg and
One group of papers covers electro-mechanical systems of surprising variety, including many innovations. Amongst these is a description of new technology for the replication of complex multifaceted mirror drums, some of which would be impossible to fabricate in the normal way. Specialist papers also include one by R.E. Hopkins on the optical
OPTICS AND LASER TECHNOLOGY
. AUGUST
1977
187
system, and one by G.J. Watt on the design of gas bearings for laser scanners. A specialized application to the study of the wake and vortex flow behind models of large aircraft is included. A challenging contribution by I.H. Mallender poses a practical and basic optical question from a development engineer’s point of view, by asking for the criteria for the optimum truncation of a coherent Gaussian light beam. He seems to have uncovered some inconsistencies in the standard optical texts, or at least some ambiguity and risk of misinterpretation. Finally, there is a short paper describing an interactive method to improve the precision of location of picture points along the scan direction by a phase-locking technique. There is much in this volume for anyone needing to understand the practical engineering of scanning systems, and for many others, too, including those with an armchair interest in the gadgetry. Though the scope is necessarily somewhat specialized, many diverse categories of devices are covered in a clear and informative way. In these respects the book fulfds the aim of the SPIE seminars, to present the essential technology and instrumentation of the specialist fields. J. W.C. Gates
Modern utilization of infrared technology civilian and military
I I,
Edited by I. J. Spiro Proceedings of the Society of Photo-Optical Instrumentation Engineers, Volume 95, 1976, pp 230, $36.00 This second volume of the SPIE Seminar Proceedings on infra-red technology follows very closely the pattern of the first, which I reviewed last year (Opt Laser Technol8 (1976) 238). There is a broad coverage of infra-red topics with a varied style of presentation as well as length and depth of treatment. The main emphasis in this volume is on infra-red astronomy (seven papers) and on environmental monitoring (eight papers). A session is devoted to each. The remaining 13 papers are somewhat arbitrarily divided into military applications and infra-red applications, largely a matter of convenience, I suspect, as the subject matter is not markedly distinct. The papers on infra-red astronomy are mostly forward looking. They describe a one metre aperture liquid helium cooled telescope to be flown on the US Space Shuttle, and a similar type of instrument to be installed in the Infra-red Astronomical Satellite - a joint Netherlands/US experiment. It will carry out whole sky surveys in a year of unattended operation, using four separate wavebands between 8 and 120 pm. Judging from the only whole page of discussion reported in those proceedings, a short paper reporting actual measurements of variable infra-red stars observed by a US Air Force satellite during 1971 to 1975 aroused more interest. Some infrared stars previously proposed as sensor calibration standards were found to be long period variables. Papers on planetary radiometers for the Mariner and Viking missions and a long wavelength (24 pm) infra-red heterodyne radiometer complete the session. Analysis of the atmosphere for pollutants and the remote detection of toxic fumes from industrial plant have become
188
a popular field for the application of infra-red techniques. The elegant method of correlation spectroscopy is much used for measuring small concentrations of pollutant gases in the atmosphere. Radiation from a spectrally broad source is passed alternately through a cell constraining a sample of the gas to be detected and through another path providing the same average absorption as the gas cell, but in a wavelength independent manner, by means of a mask or aperture. The two radiation paths are combined at a detector. The atmospheric path to be analysed is arranged to be common to both paths of the instrument, either near the source or at the detector end. If the atmosphere has any absorption lines which correlate with the sample gas, the radiation falling on the detector will be modulated in step with the path alternation because it will suffer less absorption through the gas cell. If the atmospheric absorption lines do not correlate no modulation is detected. Pollutant concentrations of less than one part in a million can be detected in this way. Several papers in this session on environmental monitoring describe applications of this ingenious technique. In the case of an airborne sensor sunlight reflected from the earth’s surface was used as the source of radiation. The remaining two sessions contain a fine mixture of papers, ranging from aerodynamic window heating in airborne imagers (including thermal conductivities in units of BTU/ft* hr ’ F/ft) to earth surveillance by satellites, and from fibre-optic communication links to the basis of radiometric calibration. There is something useful for anyone interested in the practical aspects of the infrared, although the final paper a film commentary - can be of little use outside the seminar Type faces vary as each author produced his own paper for photo-reproduction, but the standard is good. Considering this method of production the price seems high and is probably beyond the reach of the average individual. W.R. Bradford
Digital and alphanumeric a market study
information
displays:
L. Miller Electrical Research Association,
1975, pp 203, g900
As the title states, this is a market survey and not a book in the normal sense. It was produced as the result of a groupsponsored research project, in which each sponsor paid a share of the cost of production. The price, which may seem excessive, must not be judged in relation to books having fairly wide readership and extended sales life, but in comparison with the cost of commissioning a study privately, either in-house or from consulting market analysts. The study is marked ‘private and confidential’, reflecting the original limitation of circulation to those sponsors who funded it; however it is now generally available. The display device market is characterized by extraordinary complexity, both in the variety of closely competing technologies available and in the very wide range of applications in which they are used. By collecting a vast amount of information, sorting it and presenting it in clear and logical form, the author has given a valuable service. Principally the study is intended for technical and marketing managers in
OPTICS AND LASER TECHNOLOGY.
AUGUST
1977
Low light level devices for science and technology Edited by C. Freeman
Arizona to replace photographic film by video tape. At the latter university they are particularly concerned with the resolution limitation of currently available video systems and report on investigations with a high resolution system. It is some years since thermography was hailed as the certain answer to the early diagnosis of breast cancer. Following the early euphoria a greater sense of realism has prevailed, and more cautious attempts to correlate temperature variations in the human body with their underlying causes is being studied on a more quantitative basis. Some preliminary findings are reported. Of course most of the advanced equipment in the infra-red field has a military significance and for these reasons is excluded. Nevertheless this omission should not be allowed to detract from the value and interest of these proceedings. A. IV. Woodhead
Proceedings of the Society of Photo-Optical Instrumentation Engineers, Volume 78, 1976, pp 162, $36.00 This conference, which was held from 22-23 March 1976 in Reston, Virginia, brought together the whole spectrum of workers in the field of electronic image formation, from those investigating the newest devices to the astronomers, doctors and others who ultimately judge the value of the end-products by the value of the pictures which are produced. There were four sessions, the first of which attempted to bring up to date the published information on a number of imaging devices which operate in the visible and infra-red spectral range. The remaining sessions were devoted to a variety of applications but with particular emphasis on astronomy and medicine. Like all miscellaneous collections of conference papers the standard varies. Indeed some papers appear to have been included for the sake of completeness as they have little or nothing new to say. However, workers in the field will find this a very useful cross-section survey of progress in some of the main areas, while the general reader wilI also find much of interest. Predictably we find the vacuum tube intensifier being pressed by the solid-state charge-coupled and charge-injection devices, A number of papers attempt to establish the potential of these devices at very low light levels by following, sometimes rather slavishly, the simplified analysis technique developed for intensifier and camera tubes. They predict performance thresholds which equal or surpass those of present day vacuum tubes. However, there seems to be some way to go before the solid-state devices can match broadcast camera tubes in picture quality and content. It is for these reasons that most of the applications of CCDs and intensified CCDs are reported in the session devoted to astronomy.
Laser scanning components and techniques Edited by L. Beiser, G. F. Marshall
Proceedings of the Society of Photo-Optical Instrumentation Engineers, Volume 84,1977, pp 147, $36.00 The papers given at a two-day symposium held in San Diego on 24 and 25 August 1976 are presented. The field covered is concentrated on design considerations and trends in the instrumentation of devices for information-handling systems, and will be of most interest to development engineers involved in the field or in related subjects. It will also be useful to the managers, planners, and market study experts involved with this potentially very profitable area of technology. There is some derivation from earlier SPIE seminars, especially the seminar on ‘Laser recording and information handling technology’ published as Volume 53 of SPIE proceedings, which included one session on scanning and modulation. The present volume indicates how much has developed in the USA in the two-year interval, and deals with aspects of scanning technology in detail.
A few years ago there was a tendency to write-off the pyroelectric vidicon on the grounds of poor resolution and inadequate sensitivity. In this field in particular persistance seems to be bringing its rewards. Improvements already introduced, or which are now in the pipeline, could result in this tube finding a variety of uses where a good performance ( < 0.8OC minimum resolvable temperature difference at 400 tv line resolution) at moderate cost is required.
The nineteen papers are well matched and very readable. Considerations of the same field by several different authors provides an informative comparison between the specialities of competing companies. The basic common ground is the better understood for the reinforcement, in spite of apparently unnecessary duplication, but the parallel studies become most useful in extending the range of variation in applications. As might be expected, pride of place is given to a serious market potential study. For the period up to 1980 it is forecast that the information handling field will be increasingly profitable in the USA. Optical character readers, computer memories, and laser recorders will require the instrumentation now described as essential contributions to the value of the turnover estimated at something like a billion dollars.
The pressure to reduce dose rate whilst still providing the maximum amount of useful diagnostic information has long made x-ray imaging a fruitful field for the application of the techniques which were the subject of this conference. Now the cost and the space required to keep the records are stimulating attempts at the Universities of Pittsburg and
One group of papers covers electro-mechanical systems of surprising variety, including many innovations. Amongst these is a description of new technology for the replication of complex multifaceted mirror drums, some of which would be impossible to fabricate in the normal way. Specialist papers also include one by R.E. Hopkins on the optical
OPTICS AND LASER TECHNOLOGY
. AUGUST
1977
187
system, and one by G.J. Watt on the design of gas bearings for laser scanners. A specialized application to the study of the wake and vortex flow behind models of large aircraft is included. A challenging contribution by I.H. Mallender poses a practical and basic optical question from a development engineer’s point of view, by asking for the criteria for the optimum truncation of a coherent Gaussian light beam. He seems to have uncovered some inconsistencies in the standard optical texts, or at least some ambiguity and risk of misinterpretation. Finally, there is a short paper describing an interactive method to improve the precision of location of picture points along the scan direction by a phase-locking technique. There is much in this volume for anyone needing to understand the practical engineering of scanning systems, and for many others, too, including those with an armchair interest in the gadgetry. Though the scope is necessarily somewhat specialized, many diverse categories of devices are covered in a clear and informative way. In these respects the book fulfds the aim of the SPIE seminars, to present the essential technology and instrumentation of the specialist fields. J. W.C. Gates
Modern utilization of infrared technology civilian and military
I I,
Edited by I. J. Spiro Proceedings of the Society of Photo-Optical Instrumentation Engineers, Volume 95, 1976, pp 230, $36.00 This second volume of the SPIE Seminar Proceedings on infra-red technology follows very closely the pattern of the first, which I reviewed last year (Opt Laser Technol8 (1976) 238). There is a broad coverage of infra-red topics with a varied style of presentation as well as length and depth of treatment. The main emphasis in this volume is on infra-red astronomy (seven papers) and on environmental monitoring (eight papers). A session is devoted to each. The remaining 13 papers are somewhat arbitrarily divided into military applications and infra-red applications, largely a matter of convenience, I suspect, as the subject matter is not markedly distinct. The papers on infra-red astronomy are mostly forward looking. They describe a one metre aperture liquid helium cooled telescope to be flown on the US Space Shuttle, and a similar type of instrument to be installed in the Infra-red Astronomical Satellite - a joint Netherlands/US experiment. It will carry out whole sky surveys in a year of unattended operation, using four separate wavebands between 8 and 120 pm. Judging from the only whole page of discussion reported in those proceedings, a short paper reporting actual measurements of variable infra-red stars observed by a US Air Force satellite during 1971 to 1975 aroused more interest. Some infrared stars previously proposed as sensor calibration standards were found to be long period variables. Papers on planetary radiometers for the Mariner and Viking missions and a long wavelength (24 pm) infra-red heterodyne radiometer complete the session. Analysis of the atmosphere for pollutants and the remote detection of toxic fumes from industrial plant have become
188
a popular field for the application of infra-red techniques. The elegant method of correlation spectroscopy is much used for measuring small concentrations of pollutant gases in the atmosphere. Radiation from a spectrally broad source is passed alternately through a cell constraining a sample of the gas to be detected and through another path providing the same average absorption as the gas cell, but in a wavelength independent manner, by means of a mask or aperture. The two radiation paths are combined at a detector. The atmospheric path to be analysed is arranged to be common to both paths of the instrument, either near the source or at the detector end. If the atmosphere has any absorption lines which correlate with the sample gas, the radiation falling on the detector will be modulated in step with the path alternation because it will suffer less absorption through the gas cell. If the atmospheric absorption lines do not correlate no modulation is detected. Pollutant concentrations of less than one part in a million can be detected in this way. Several papers in this session on environmental monitoring describe applications of this ingenious technique. In the case of an airborne sensor sunlight reflected from the earth’s surface was used as the source of radiation. The remaining two sessions contain a fine mixture of papers, ranging from aerodynamic window heating in airborne imagers (including thermal conductivities in units of BTU/ft* hr ’ F/ft) to earth surveillance by satellites, and from fibre-optic communication links to the basis of radiometric calibration. There is something useful for anyone interested in the practical aspects of the infrared, although the final paper a film commentary - can be of little use outside the seminar Type faces vary as each author produced his own paper for photo-reproduction, but the standard is good. Considering this method of production the price seems high and is probably beyond the reach of the average individual. W.R. Bradford
Digital and alphanumeric a market study
information
displays:
L. Miller Electrical Research Association,
1975, pp 203, g900
As the title states, this is a market survey and not a book in the normal sense. It was produced as the result of a groupsponsored research project, in which each sponsor paid a share of the cost of production. The price, which may seem excessive, must not be judged in relation to books having fairly wide readership and extended sales life, but in comparison with the cost of commissioning a study privately, either in-house or from consulting market analysts. The study is marked ‘private and confidential’, reflecting the original limitation of circulation to those sponsors who funded it; however it is now generally available. The display device market is characterized by extraordinary complexity, both in the variety of closely competing technologies available and in the very wide range of applications in which they are used. By collecting a vast amount of information, sorting it and presenting it in clear and logical form, the author has given a valuable service. Principally the study is intended for technical and marketing managers in
OPTICS AND LASER TECHNOLOGY.
AUGUST
1977