1st Edition
Thermal Imaging Cameras Characteristics and Performance
The ability to see through smoke and mist and the ability to use the variances in temperature to differentiate between targets and their backgrounds are invaluable in military applications and have become major motivators for the further development of thermal imagers. As the potential of thermal imaging is more clearly understood and the cost decreases, the number of industrial and civil applications being exploited is growing quickly. In order to evaluate the suitability of particular thermal imaging cameras for particular applications, it is important to have the means to specify and measure meaningful performance characteristics.
Thermal Imaging Cameras: Characteristics and Performance expands our current understanding of thermal imaging and, most importantly, provides a sound quantitative basis for evaluating the suitability of various thermal imagers for particular applications. Utilizing a practical approach that keeps theory and mathematics to a minimum, the text reviews the important performance parameters for industrial, laboratory, and surveillance applications as well as how these parameters can be measured. The author, T. L. Williams, a distinguished expert on designing and testing thermal imaging systems and recipient of the Callendar Medal from the Institute of Measurement and Control, focuses on the standard form of imaging camera but also includes descriptions of the different specialized forms of thermal imagers useful to anyone working with these systems.
Providing detailed descriptions of the equipment and techniques that can be used for testing complete thermal imagers as well as in the testing of the main subunits of a thermal imager, this comprehensive reference will prove invaluable not only to those who use, test, and design thermal imagers, but also to anyone designing equipment or making measurements in the thermal band of wavelengths.
Preface: Thermal Imaging Cameras
Biography
Symbols and Abbreviations
An Introduction to Thermal Imaging
Aim of This Book
What Is Thermal Imaging?
Atmospheric Transmission
Choice of 3–5 µm or 8–12 µm
Important Factors in the Application of Thermal Imaging
Specifying and Measuring the Performance of a Thermal Imager
Thermal Imaging Cameras and Their Component Parts
A Basic Thermal Imager
Image-Forming Optical System
Windows for Thermal Imaging
Scanning Mechanisms
Radiation Detectors
Cooling Detectors
Special Signal Processing and Other Requirements
Displays
Computer and Software
References
Industrial and Commercial Thermal Imagers and the Facilities
They Provide
Introduction
Thermal Imagers That Measure Actual Temperature
Software Facilities for Industrial Applications
Thermal Imagers for Surveillance Types of Application
Imagers Used by Firefighters
Manufacturers’ Data Sheets
References
Performance Parameters for Components of a Thermal Imager
Introduction
Lenses
Detectors
Scanners
Displays
References
Performance Parameters for a Complete Thermal Imager
Introduction
Factors Affecting Performance
Performance Parameters
Frame Rates and Readout Timings
Other Factors
References
Basic Equipment for Testing and Calibrating at Thermal Wavelengths
Introduction
Radiation Sources
Infrared Detectors
Cooling Detectors
Optical Systems and Collimators
Integrating Spheres
Spectral Filters
References
Measurement Procedures and Techniques for the Principal
Components that Make Up a Thermal Imager
Introduction
General Measurement Procedures
Lenses and Optical Systems (see also Section 4.2)
Detectors and Detector Arrays
Scanners
Displays
References
Measurement Techniques and Procedures for Complete
Thermal Imagers
Introduction
MTF
Nyquist Limit
Aliasing
Signal Transfer Function (SiTF)
Noise-Equivalent Temperature Difference (NETD)
Minimum Resolvable Temperature Difference (MRTD)
Minimum Detectable Temperature Difference (MDTD)
Objective MRTD
Objective MDTD
Slit Response Function (SRF)
Aperture Response Function (ARF)
Temperature Measurement Performance Characteristics
Emissivity Range
Narcissus
Veiling Glare Index (VGI) and Uniformity Index (VGUI)
Scene Influence Factor (SIF)
Field of View (FOV)
Close Focus Distance
Spectral Response
References
Calibration and Alignment of Test Facilities
Introduction
Calibrating and Aligning a Collimator
Radiometric Characteristics
References
Applications of Thermal Imaging Cameras
Introduction
Industrial Applications
Advanced and Specialist Applications
Medical and Biological Applications
Military and Civil Surveillance and Other
Applications
References
Appendix A: Objective Measurement of MRTD and MDTD
Performance Parameters That Determine MRTD and MDTD
Theory for MRTD Measurement
Theory for MDTD Measurement
References
Appendix B: Sampled Imaging Systems and Aliasing
What Are Sampled Imaging Systems?
Image Formation by Sampled Imaging System
Basic Theory
Measures of Aliasing
MTF Measurements Techniques
References
Biography
Thomas Williams
