NIGHT VISION REFERENCE BOOK

BOOK REVIEW, By D.LL. Silbergeld - SO/LIC NEWS, JANUARY 2000ELECTRO-OPTICAL SURVEILLANCE (Vol. 3, Security Source Library) by Gene Adcock.

The CCS Security Publishing, Ltd. ($300.00) book has 700-pages covering almost every aspect of Night Vision systems and technology, both image intensification and thermal imagery.

From World War II to Operation Desert Storm, the history of Night Vision equipment development is detailed in illustrations and diagrams and carefully spelled out.

The physics of Night Vision Equipment (NVE) is provided along with the principles of optics, and the differences between image intensification and thermal imaging demonstrated along with the systems that were developed using the different generations as they became available.

The book discusses the application of such imagery for both military and civilian use. There are few, if any books of this depth available outside of individual service technical manuals produced for and by the military establishments.

The author, Gene Adcock brings to the creation of this book, a broad spectrum of practical experience both in the development of new and innovative products as well as the sale of those products for the many military and civilian applications of surveillance equipment.

Gene has been a consistent contributor to the SO/LIC Community and to the SO/LIC Division of NDIA.

Available from Night Vision Equipment Company, call 1-800-797-2849.

Price is discounted at $200.00 for US Government orders delivered to a CONUS address. (Reprinted with Permission, National Defense Industrial Association, http://www.ndia.org)Excerpts from Electro-Optical Surveillance

--------------------------------------------------------------------------------

Chapter 1 - AMERICAN PIONEERS IN ELECTRO-OPTICAL SURVEILLANCESample Figure - Figure 1-3. NIR Sniperscope - Circa 1952 (Photo Courtesy of NVEC)This chapter traces the path of key American pioneers who were responsible for the development of image intensified and thermal detection electro-optic devices. Although both concepts existed on paper and in the minds of many scientists as early as the 1930s, the technology to support the theories wasnât available until the 1950s.

--------------------------------------------------------------------------------

Chapter 2 - LIGHT AND ELECTROMAGNETIC SPECTRUM (58 Pages)Sample Figure ö Figure 2-12, The Electromagnetic SpectrumNearly all the earth's light comes from our nearest star, the sun, which is a whirling cloud of very hot gasses. These gasses glow very brightly, emitting (giving out) light.All hot things give out light, even people, who emit invisible infrared light. Other natural sources of light on Earth come from lightning, fire, and the rest of the stars. Insects, such as fireflies, and some deep-sea fish, glow as a result of chemical reaction that releases light. We can create artificial light by burning fuels in lamps, and by producing electricity for light bulbs. In this chapter, you will learn about the electromagnetic spectrum, and the wavelengths of light to which our eyes and electro-optical surveillance systems are most sensitive.

--------------------------------------------------------------------------------

Chapter 3 - BASIC OPTICAL INSTRUMENTS (82 Pages)Sample Figure - Figure 3-12. The normal eye and two common aberrationsThis chapter discusses optical elements and the principle of operation of some basic optical instruments. The knowledge you gain in this chapter will enable you to better understand the discussion of image-intensified devices and thermal viewers in the following chapters. For the simplicity sake and ease of understanding, the optical devices addressed in this chapter do not incorporate image tubes or thermal sensors, they are discussed in later chapters. Although we seldom think of them as such, our eyes are optical instruments with built-in adjustments that enable us to see objects close at hand and at variable distances. An understanding of the functioning of the human eye will therefore help you to more easily understand the operation of optical instruments that are discussed in detail in the second half of this chapter.

--------------------------------------------------------------------------------

Chapter 4 - IMAGE INTENSIFICATION (83 Pages)Sample Figure - Figure 4-28. GEN II image intensifier tube cross section showing placement of microchannel plate between the photocathode and the phosphor screen, which is the element viewed by the userThe human eye and many man-made devices such as radio, television, and image intensified night vision devices operate at different wavelengths within a continuum that may be termed the spectrum of electromagnetic radiation. The eye and each of the various man-made devices are tuned to a specific wavelength or band of wavelengths within this spectrum. Each is, therefore, sensitive only to a certain portion of the spectrum. An image intensified night vision device can be compared to, but is simpler than, an ordinary radio. A radio detects electromagnetic wavelengths or frequencies that are not detectable by the human ear. The radio processes this energy into audio frequencies, and outputs them through the radioâs loudspeaker in the form of acoustic radiation or sound that can be detected by the human ear.Similarly, an image intensified night vision device detects both minute levels of light energy and wavelengths that are outside the detection range of the human eye; converts these electromagnetic waves into electrical energy; processes and amplifies it; and outputs the energy through a phosphor screen in the form of visible energy or light that can be detected by the human eye.The techniques of conversion and amplification of these light waves involve two disciplines: electronics and optics, hence the contraction electro-optics. The basic understanding of each, as they relate to night vision devices, will assist the user in evaluating and choosing the equipment most useful to his operational needs. In this chapter, the capabilities and limitations of numerous image intensified night vision devices will be discussed in detail.

--------------------------------------------------------------------------------

Chapter 5 - IMAGE INTENSIFIED NIGHT VISION SYSTEMS (110 Pages)Sample Figure - Figure 5-67. Varoâs ö now Litton - Model 90 is a 12x version of the AN/PVS-10. It is designed for larger weapon systems such as the 50-caliber sniper rifle shown in this photograph. (Photograph of preproduction sniper sight courtesy of Varo, Inc.- now Litton)In the first half of the 20th Century, nightfall marked the time when enemies were nearly impossible to locate on the battlefield. While some stealthy fighters have always tried to take advantage of the night and more than a few criminals prefer the darkness to practice their skills until recently, friend and foe were equally blind.In the last half-century, combat operations added a new night fighting capability, night vision equipment. The equipment most commonly used for many paramilitary organizations and US Military was, and continues to be, image intensified night vision equipment. These night vision devices use an objective lens to collect whatever tiny amount of light and near infrared is available at night from sources such as moonlight or starlight, focusing the resulting image onto the input photocathode of an image intensifier tube. The incoming photons strike the photocathode, releasing electrons in proportion to the amount of radiation that has arrived. The resulting electron image is amplified, then reconverted to create a visible display.

--------------------------------------------------------------------------------

Chapter 6 - INFRARED THERMAL DETECTION (58 Pages)Sample Figure - Figure 6-1. Thermal image photograph taken with Texas Instruments/Hughes Aircraft Company joint-venture NIGHTSIGHT Thermal Vision System (Photograph courtesy of Texas Instruments)Infrared imaging systems arenât exactly new. Since the 1960s, theyâve been used by the military in heat-seeking missiles, as hand-held personnel and vehicle detectors, for search and rescue operations, and search and destroy missions.Every object emits electro-magnetic radiation that infrared imaging systems can see. Cold objects radiate relatively little electro-magnetic radiation, while hotter objects radiate much more electro-magnetic radiation. The radiation spectrum emitted by hot objects differs from that of cold objects. Extremely hot objects such as the sun emit much of their radiation as visible light. Cooler objects, such as trees, people and automobiles, emit most of their radiation in the lower-energy infrared (IR) part of the spectrum. The human eye cannot detect this radiation, but IR-sensitive detectors can.Infrared detectors are classified as either photon detectors or thermal detectors. Photon detectors, usually photoconductors or photodiodes, produce an electrical response directly as the result of absorbing IR radiation. These detectors can be very sensitive, but their noise producing mechanisms depend strongly on temperature. It is necessary to cryogenically cool these detectors to maintain high sensitivity.Thermal detectors experience a temperature change when they absorb IR radiation, and an electrical response results from the temperature dependence of some material property. These detectors are thermally isolated from their immediate surroundings to maximize the temperature change that results from the absorption of a small amount of IR radiation. Thermal detectors are not generally as sensitive as photon detectors, but they retain a good level of performance at room temperature. This enables the fabrication of IR imaging systems that do not require cryogenic cooling.This chapter defines thermal imaging and explains the operation of thermal detectors; it describes their capabilities and shows their limitations from a technical point of view. In Chapter 7, several thermal imaging systems and their operational uses are discussed in detail.

--------------------------------------------------------------------------------

Chapter 7 - THERMAL IMAGING SYSTEMS (62 Pages) Sample Photo ö Figure 7-17, The TWS Light Weapon Thermal Sight configuration is the smallest of three models. The unit shown here is mounted on a specially configured M16. (Photograph courtesy of Hughes Electro-Optical Systems, El Segundo, CA)A large number of sophisticated infrared (IR) image sensors and systems with spectral response extending into the far IR have been developed and are available at reasonable cost for a wide variety of applications because of the many qualitative and quantitative demands of the military, industrial, and medical communities. Since the early 1960s, many thermal imaging devices and systems were investigated, but most were limited in performance or were cumbersome and expensive. Charge coupled devices (CCDs), one of the more important thermal image sensors, were first used in strategic and ecological reconnaissance and surveillance both on the ground and in the air. They are now employed in a wide range of thermal imaging systems because they are lightweight, relatively inexpensive, are available with spectral response extending out to the far IR, and are quite reliable. Four wavelength regions of the IR spectrum can be used in thermal imaging. These include the near infrared with wavelengths of about 1 micron, and other windows at 2 - 2.5 microns, 3.5 - 4.2 microns, and 8 - 14 microns. Detection in other parts of the spectrum is restricted by atmospheric absorption in water and carbon dioxide molecules.Imaging in all these regions can be carried out with ambient or active illumination, but for wavelengths greater than 3 microns, the objectâs thermal blackbody radiation is often used for thermal imaging. However, the contrast of thermal images is very low and, particularly in the 8 - 12 micron portion of the spectrum, where most of the thermal radiation energy is concentrated, it is only about one percent per degree centigrade. The uniformity requirements of image system responsivity in this region are very severe and can only be met with special operational techniques because a thermal resolution of 0.1-degree Centigrade is typically desired.

--------------------------------------------------------------------------------

Chapter 8 - SYSTEMS APPLICATIONS (63 Pages)Sample Photo - Figure 8-15, Two views of the sake scene show how thermal imaging system can detect a person (upper photo) that is invisible to a GEN III image intensifier system (lower photo). (Photographs courtesy of Texas Instruments, Dallas, Texas.)Night vision technology is quickly becoming a powerful tool for scientific, surveillance, security and law enforcement agencies around the world. Many of these products migrated from the military and are now available to paramilitary, civil and commercial users for a variety of applications. Night vision devices fall into two categories: Image Intensification (I2) devices and Forward Looking Infrared (FLIRs or IR) Thermal Imagers. Often misunderstood, each employ different technologies and are very effective crime fighting and surveillance tools.

--------------------------------------------------------------------------------

Chapter 9 - THE END OF AN ERA (19 Pages) Sample Picture - Figure 9-1, Delftâs HNV-3D, Holographic Night Vision Goggles (Photo courtesy of Delft Sensor Systems)This chapter summarizes the events that occurred in the final years of the 20th Century. During that period there were dramatic improvements in both image intensified and thermal imaging systems, although most work was concentrated in the image intensifier arena.The image intensification system improvements happened because night vision goggles are widely distributed throughout the US Military, they are relatively inexpensive, and there was strong support for the systems in both the military and industry; however, thermal imaging is the wave of the future.The military has an obsession about developing a lightweight and affordable thermal system that can see through battlefield obscurants. Since the 1980âs, heavy thermal systems have been effectively used in airplanes, helicopters and tracked vehicles. For example, thermal sensor videos of smart bombs crashing through buildings were common viewing on the evening news during Operation DESERT STORM. The Military wants, and is developing a lightweight thermal viewing capability.By the year 2010, lightweight systems will be widely used on individual weapons, and a head-mounted system will be fielded. Additionally, hybrid systems, incorporating the best capabilities of image intensification and thermal will be fielded with many special units. This hybrid combination is labeled by many in the night-vision community as the next generation Generation IV (GEN IV) &Mac178; night vision system.

--------------------------------------------------------------------------------

ABOUT THE AUTHOR - Gene Adcock, Vice President, Night Vision Equipment Company (NVEC), Inc. holds Masters and Bachelors Degrees in Business and Economics. A retired US Air Force Combat Controller with more than eighteen years on jump status; he logged more than 300 static line and 100 HALO parachute jumps. During the period 1965-1971, he served four combat tours in Southeast Asia; one in Vietnam and three with an Air Commando group in Northern Laos supporting air operations against the Ho Chi Minh trail. His combat awards and decorations include Aircrew Badge, Master Parachutist Badge with Combat Star, two Bronze Star Medals, six Air Medals, six Air Force Outstanding Unit Awards with Combat "V" and two Meritorious Service Medals. After retiring as a Chief Master Sergeant, he became actively involved the development, marketing and sales of specialty devices for survival, escape, rescue, evasion, drop/landing zone operations and night tactical operations.