Sharp / Havens Thermal Imaging Techniques to Survey and Monitor Animals in the Wild

A Methodology
1. Auflage 2015
ISBN: 978-0-12-803385-2
Verlag: Academic Press
Format: EPUB
Kopierschutz: 6 - ePub Watermark

E-Book, Englisch, 376 Seiten, Format (B × H): 152 mm x 229 mm

Thermal Imaging Techniques to Survey and Monitor Animals in the Wild: A Methodology provides a manual for anyone interested in understanding thermal imaging and its usefulness in solving a wide range of problems regarding the observation of wildlife.

In the last decade, the cost of thermal imaging technology has significantly decreased, making the equipment more widely available. This book offers an overview of thermal physics and the thermal imager, along with a methodology to optimize the window of opportunity so that wildlife can be observed and studied in their natural habitat.

Users will find the knowledge and tools to formulate a sound survey design, with detailed sections on the theory and performance characteristics of thermal imaging cameras utilizing cooled quantum detectors as the sensitive element and additional information on the uncooled micro bolometric imagers which have been introduced into the camera market in past decades.

The methodology presented is logical and simple, yet it presents a detailed understanding of the topic and how it applies to the critically interlinked disciplines of biology, physics, micrometeorology, and animal physiology.



- Covers the technical aspects of thermal imaging allowing readers to design better experiments
- Provides a clear description of the properties of thermal imaging
- Includes approaches to consider before integrating thermal cameras into a field

Zielgruppe

<p>field biologists, resource managers, wildlife researchers, agricultural researchers</p>

Autoren/Hrsg.

Sharp, Edward J.

Havens, Kirk J

Fachgebiete

• Naturwissenschaften Agrarwissenschaften Agrarwissenschaften
• Geowissenschaften Umweltwissenschaften Umweltmanagement, Umweltökonomie
• Naturwissenschaften Biowissenschaften Biowissenschaften Terrestrische Ökologie

Inhaltsverzeichnis

Preface

1: Introduction

2: Background

3: Remote Sensing

4: Heat Transfer Mechanisms

5: Optical Radiation

6: Emissivity

7: Thermal Imagers and System Considerations

8: Selecting an Imager

9: Properties of a Thermal Signature

10: Review of Thermal Imaging Applications

11: Optimizing the Detectability (Creating a Window of Opportunity)

12: On the Horizon

References

Leseproben

Preface
Over the past few decades there has been a marked increase in areas of remote sensing, including thermal imaging, to study and count wildlife in their natural surroundings. While much of the work with thermal imagers to date has been devoted to testing equipment during surveys, little advancement has actually been achieved. This is primarily due to three basic problems: 1. Early field studies were conducted with cryogenically cooled thermal imagers (photon detectors) with sensitivities an order of magnitude lower than those available today. With few exceptions, the new and improved models of thermal imagers with superior sensitivities and resolution have not been used in the field because of the perceived difficulty in data acquisition and to some extent limited availability and cost. The more recent fieldwork has been for the most part confined to the use of uncooled bolometric cameras that use thermal detectors as opposed to photon detectors. 2. A pervasive misunderstanding of what thermal imagers detect and record and what ultimately constitutes ideal conditions for conducting thermal imaging observations. 3. The promulgation of results that have erroneously compared survey data collected with thermal imaging equipment to that obtained with standard techniques such as spotlighting or visual surveys. In this volume, we spend considerable effort reviewing the literature and pointing out fallacies that have been built upon as a result of these problems. This book presents a methodology for maximizing the detectability of both vertebrates (homotherms and poikilotherms) and invertebrates during a census or survey when using proper thermal imaging techniques. It also provides details for optimizing the performance of thermal cameras under a wide variety of field conditions. It is intended to guide field biologists in the creation of a window of opportunity (a set of ideal conditions) for data gathering efforts. In fact, when thermal imaging cameras are used properly, under ideal conditions, detectivity approaching 100% can be achieved. Recent attempts of researchers and field biologists to use thermal imagers to survey, census, and monitor wildlife have in most cases met with limited success and while there are a number of good books that treat the theory and applications of remote sensing and thermal imaging in significant detail for applications in land mapping, construction, manufacturing, building and vehicle inspections, surveillance, and medical procedures and analyses (Barrett and Curtis, 1992; Budzier and Gerlach, 2011; Burney et al., 1988; Holst, 2000; Kaplan, 1999; Kozlowski and Kosonocky, 1995; Kruse et al., 1962; Vollmer and Mollmann, 2010; Williams, 2009; Wolfe and Kruse, 1995), they contain very little on how wildlife biologists should go about using this equipment in the field to survey and monitor wildlife. This book provides detailed information on the theory and performance characteristics of thermal imaging cameras utilizing cooled quantum detectors as the sensitive element and also the popular uncooled microbolometric imagers introduced into the camera market in the past decades, which rely on thermal effects to generate an image. In addition, there are numerous excellent texts devoted to survey design and statistical modeling to aid in the monitoring and determination of wildlife populations (Bookhout, 1996; Borchers et al., 2004; Buckland et al., 1993; Buckland et al., 2001; Caughley, 1977; Conroy and Carroll, 2009; Garton et al., 2012; Krebs, 1989; Pollock et al., 2004; Seber, 1982, 1986; Silvy, 2012; Thompson et al., 1998; Thompson, 2004; Williams et al., 2001), but they do not include the treatment of thermal imaging capabilities to help achieve these tasks. This book is being offered as a bridge between the two technologies and the teachings presented in these excellent volumes so that their combined strengths might be united to improve upon past efforts to assess animal populations and to monitor their behavior. Even though there has been a technological disconnect since the earliest field experiments, there has still been a considerable amount of work carried out by biologists using thermal imagers to study and monitor wildlife. These studies began in the late 1960s and early 1970s when cryogenically cooled thermal imagers using photon detectors were first used for surveys and field work (Croon et al., 1968; Parker and Driscoll, 1972) and this phenomena continued to grow as thermal imagers became more readily available to field biologists. At the time, these early cameras were acknowledged as being only marginally sensitive for the task of aerial surveying. The more recent introduction of the low-cost uncooled bolometric cameras generated a new wave of experimentation with thermal imagers in the field. The sensitivity and range of bolometric cameras are limited due to the fact that they rely on a thermal process to generate an image. So we see at the start that all thermal imagers are not the same and if they are used in the field they must be used to exploit the strengths of the particular imaging camera so that reliable data can be obtained. There are appropriate uses for imagers utilizing photon detectors where high sensitivity and long ranges are characteristics making them suitable for surveying applications. There are also applications suitable for imagers fitted with thermal detectors that have lower sensitivities and ranges. Their advantages are their availability, cost, and that they are uncooled. Field applications favoring bolometric cameras that do not require long ranges or high sensitivity will also be addressed in this book. The process of using thermal imagers as a tool to collect field data has been compared with other data collection techniques; however, in nearly all cases the thermal imager was not used correctly and perhaps was even inadequate for the task. This practice has led to a number of misconceptions about the basic use of a thermal imager and the correct interpretation of the results. There is a big distinction between thermal imagers that utilize quantum detectors as the sensitive element and detectors that rely on thermal effects to generate an image. The differences are enormous as far as fieldwork goes for censusing and surveying, particularly on a landscape scale. Unfortunately, a text describing the use of 3–5 and 8–12 µm photon detectors for animal surveys and field studies has not emerged. This is probably due to the fact that 3–5 and 8–14 µm imagers were not widely used since the first field experiments. These experiments used cryogenically cooled units typically borrowed from military installations. These robust units are now becoming available at a reasonable cost and should see increased use by field biologists. An excellent text describing the practical use of pyroelectric and bolometric imagers for a wide range of applications has been written (Vollmer and Mollmann, 2010) and a number of distinctions are pointed out between these imagers and those using photon detectors as the focal plane. Past work using thermal imagers in the field has mainly been carried out so that comparisons could be made with other data gathering methods. From the outset we see that comparing the results obtained with thermal imagers with that of data collected with other methods such as spotlighting and visual surveys must necessarily be skewed and these efforts, while commendable, do not allow for a fair comparison of the data collection capability of the compared techniques. Thermal cameras are suitable for surveys and counts throughout the 24-h diurnal cycle while other methods are not. These studies by their nature and design mean that the results of data collected with a thermal imager will be compared with data collected using a method that was optimized for the conditions of the survey at hand. For example, consider the comparison of data collected during a visual survey and the data collected via thermal imagery using the same temporal and spatial conditions. Note that the survey must be conducted during daylight hours because the visual spotters need daylight to see the animals of interest. Thermal cameras can also detect the animals of interest during daylight hours but there are concomitant conditions required for the optimization of the thermal survey if it is conducted during daylight hours. These conditions can be met in a relatively easy manner but were not generally addressed during these past comparisons so the results reported were skewed and in some cases grossly inaccurate. We review many of these comparisons and offer alternatives. A variety of statistical methods, such as distance sampling and mark recapture, among others, were used for estimating the abundance of animal populations in these comparisons and the results of these studies were built upon by others. We do not treat these statistical methods here but point out that each of them has strengths and weaknesses (Borchers et al., 2004), depending on the species of the animal being surveyed. All will benefit from data collection methods that produce a detectability (see Chapter 1) that approaches ~100%. The widespread dissemination of these results is the existing foundation that later work has been built upon and it has led to a confusing and widespread misunderstanding of the capabilities of thermal imaging as a powerful survey tool in these applications. This distribution of erroneous or badly skewed information regarding the...

Über Autor(innen)

Sharp, Edward J.
Ed Sharp was born in Uniontown, PA, attended Wheeling College and John Carroll University and received the Ph.D. degree from Texas A&M University in 1966. He conducted basic research in the area of applied nonlinear optics at the U. S. Army Night Vision & Electro-Optics Laboratory and the U. S. Army Research Laboratory. Presently he is working as a consultant on the use of infrared imaging equipment in novel application areas. His major areas of interest include laser crystal physics, thermal imaging materials and devices, electro-optic and nonlinear-optical processes in organic materials, beam-control devices, optical solitons, harmonic generation, optical processing, holographic storage, photorefractive effects in ferroelectric materials and the study of animal ecology using thermal imaging equipment. He is the author or co-author of more than 100 technical publications and holds over 15 patents on optical materials and devices. He is a member of the American Optical Society. Presently he has been working on new methods for using thermal imaging to address issues related to animal ecology and natural resource studies with faculty at the Virginia Institute of Marine Science (VIMS), College of William & Mary.