Thermal Imaging: Types, Advancements and Applications PDF

Complimentary Contributor Copy  CONTENTS Preface vii Chapter 1 Thermal Imaging Cameras in the Detection of Human Cadaveric Remains 1 Angel M. DesMarais Chapter 2 Passiv...

Complimentary Contributor Copy  CONTENTS Preface vii Chapter 1 Thermal Imaging Cameras in the Detection of Human Cadaveric Remains 1 Angel M. DesMarais Chapter 2 Passive and Active Thermography for the Detection of Subsurface Malignant Lesions 25 Arka Bhowmik and Ramjee Repaka Chapter 3 Application of Thermal Imaging for the Assessment of Body Composition in Humans 61 Ana Carla Chierighini Salamunes, Adriana Maria Wan Stadnik and Eduardo Borba Neves Chapter 4 Challenges of Thermographic Image in Medical Applications 81 Tania Pereira and Ricardo Simoes Index 103 Complimentary Contributor Copy In: Thermal Imaging ISBN: 978-1-53612-128-5 Editor: Claude Strickland © 2017 Nova Science Publishers, Inc. Chapter 1 THERMAL IMAGING CAMERAS IN THE DETECTION OF HUMAN CADAVERIC REMAINS Angel M. DesMarais Forensic Pathology and Legal Medicine, Providence, RI, US ABSTRACT Detection of cadaveric remains using Thermal Imaging (TI) is a relatively new concept. Recent studies support the usefulness of continued use of TI in later stages of Missing Person’s searches, when the hope for recovering the person alive has diminished, and the search has been deemed a recovery. Searching for missing persons usually involves difficult terrain often times of densely forested environments that are not conducive to aerial searches. Ground searches involve lines of volunteers visually inspecting the area assigned as the group advances over a given location. TI is a standard piece of equipment often utilized during the initial phase. However, in the later stages during the search many of the resources may be retracted and hope of finding the body dwindles.  [email protected]. Complimentary Contributor Copy 2 Angel M. DesMarais Recent studies have proven the continued use of hand held TI cameras can increase the likelihood of a recovery even as late as the advanced decay stage by using heat signatures from colonizing insects on the cadaver. Time frames can be determined based on seasonality, weather, size and mass of the individual to maximize the search efforts without added cost of new equipment. Future research into depth that TI can detect clandestine shallow burials would provide useful to law enforcement as it would enable the recovery of not only the victims but important evidence that would lead investigators to the perpetrators of the crimes. 1. INTRODUCTION Thermal Imaging has been used in a wide variety of ways, only recently has its application to Forensic Anthropology been explored as a means of detection of missing persons cadaveric remains (DesMarais, 2014). Thermal imaging began as a means for combat personnel to detect heat signatures of individuals at night, later it was adapted by forestry and law enforcement to locate individuals in large areas from the air in low light (night) conditions (Maurer, Driggers, & Wilson, 2005) (Leonardo, 1961) (Killam, 2004) (Geddes, 2010) (France, et al., 1992) (De Loor, 1969) (Workman, 2001). Fire personnel adapted TI further, making handheld versions that are capable of functioning in adverse conditions, durable and compact enough for use in outdoor settings while continuing to image at great distances detecting objects with heat signature differences of fractions of a degree (Amon, Bryner, Lock, & Hamins, 2008). Most fire departments have TI cameras and utilize them during search and rescue events when a person has been reported missing. The Fire fighters who are active members of Search and Rescue teams will use them during the initial search but suspend their use during the later stages when the mission changes from a rescue to a recovery; when the likelihood of finding the person alive has diminished. Recently it’s been shown that the use of TI can continue into the later portion of the missing persons search; the recovery phase incorporating the postmortem interval, utilizing the heat signatures from decomposition and Complimentary Contributor Copy  Thermal Imaging Cameras in the Detection … 3 the extreme thermal signatures of insect larvae which is dependent on time, temperature, and cadaver mass (DesMarais, 2014). Thermal imaging of cadaver detection works best in low light (night) conditions, during times when temperatures fall in the optimum temperature range for insect activity (50 to 95 °F) (Leonardo, 1961) (Block, Baust, Franks, Johnston, & Bale, 1990). If the search is during a timeframe that is not conducive to insect activity the recovery can potentially be continued when the temperature again reaches the optimum threshold (barring scavenging from predators during that paused timeframe), and decomposition would continue in a natural progression. The operator of the TI would view the heat signatures from decomposition and insect larval masses as increasingly bright amorphous forms of light that, as the larval masses increase in size, more closely register a heat signature that resembles the remains as a whole. When the masses are at their largest, during the active decay stage, they can be detected at a distance of over 114 feet (DesMarais, 2014). Although detection of cadaveric remains in above ground settings brings closure to some families future directions in the use of TI would encompass both the forensic field by detection of clandestine graves bringing justice to the perpetrators with the likelihood they would be held accountable for the misdeeds they inflicted on their victims, and the archaeological potential for site identification which would expand our knowledge of past peoples. 2. THERMAL IMAGING All objects over absolute zero temperature emit infrared energy; this type of energy is found beyond the visible light spectrum, having longer wavelengths than visible light. Typically thermal imaging cameras (TIC) view warmer objects, objects emitting more infrared energy (IR) as white while cooler objects would display as shades of gray or color (Woodworth, Thermal Imaging for the Fire Service, Part 3: Thermal Characteristics, 1996). Complimentary Contributor Copy 4 Angel M. DesMarais The first infrared sensitive cameras developed in 1929 were used by the British military for antiaircraft defense (Wimmer, 2011). Nearly 20 years later, an infrared line scanner (taking over an hour to produce a single image) was developed (Palmer Wahl Instrumentation Group, 2007). The US military saw the value in these detectors and classified the technology for sensitive military applications. It wasn’t until 1966 that the first real-time imager was developed, paving the way a few short years later for the first thermal imager used by the Royal Navy for shipboard firefighting (Palmer Wahl Instrumentation Group, 2007) (Wimmer, 2011). Prior to 1991 thermal imagers were cost prohibitive. Due in part to continued governmental contracts for development of TI technology, the practical application expanded to assisting the military personnel in combat situations at night by detecting heat signatures of combatants (Maurer, Driggers, & Wilson, 2005) (Wimmer, 2011). This drove production up and cost down. After the Gulf War the cost decrease led the way for thermal imaging into many different industries. 1994 saw the commercial application of thermal imaging with law enforcement, forestry personnel and border patrol by utilizing TI in searching large areas at night from the air for individuals on the ground (Leonardo, 1961) (Killam, 2004) (Geddes, 2010) (France, et al., 1992) (De Loor, 1969) (Workman, 2001). Firefighting needs took the technology a step further making the hand held cameras lightweight and durable with the ability to function in adverse conditions. The readings can be viewed on a built in monitor (Figure 1) or as with some models the image is sent wirelessly to a monitor at the incident command. With the advent of Lithium Ion batteries the handheld TIC could be utilized for over four hours on a single charge (Palmer Wahl Instrumentation Group, 2007). 2.1. Missing Persons Searches Many firefighters are members of Search and Rescue teams, realizing the potential TI would have in locating missing individuals they began Complimentary Contributor Copy  Thermal Imaging Cameras in the Detection … 5 utilizing them during search and rescue missions when a person has been reported missing. The structural framework of Search and Rescue teams are much the same as Incident Command Systems (ICS) they are designed to expand or contract as the mission dictates (ASTM, 2014) (Department of Homeland Security, 2008) (Volunteers in Police Service Program, 2010). Each Search and Rescue team will typically consist of an emergency manager who works with elected officials ensuring unified objectives of the activities. They coordinate the components of the mission regarding availability and readiness of resources, correcting for shortfalls, and may call on mutual aid as the situation dictates. Department heads (fire, police, EMS, etc.) collaborate with the emergency manager ensuring that specific capabilities are integrated and that the members have met and maintain the proper training necessary (Riker, 2002). Emergency responders make up the recovery teams under the department heads. While all working toward a common goal, the members bring with them unique specializations that can be called on should they be needed; divers, canine handlers, tracking and communications experts among others. Typically missing person searches are dictated by the conditions of the event itself. Age of the individual, weather, terrain and time of day these all play a part in directing the size, duration and equipment required (Department of Homeland Security, 2008). The emergency manager uses the event information to decide not only how few or many members are needed to adequately search but also decides when the mission should evolve from a rescue to a recovery. It is during this transition that the majority of the resources are recalled including thermal imagers. In the search for a presumed deceased individual fewer volunteers are allocated, and those specializing in cadaver searches are retained or employed. Forensic anthropologists and cadaver dog teams head up the remainder of the search parties until the search itself is called off. Despite the advanced training of these professionals to locate postmortem and osseous remains, the search is still remarkably difficult as cadaveric remains in the later stages of decomposition blend with the surroundings as leaf litter and ground cover obscure the remains. While cadaver dogs are Complimentary Contributor Copy 6 Angel M. DesMarais reported to be highly acute at finding remains they are limited by availability, the area to be covered, and terrain. The availability of these two specific resources is also sporadic and may require monetary compensation for their expertise. Coupling TI use with these trained professionals would increase the potential of locating the missing person exponentially. 3. DECOMPOSITION Recently it has shown the potential of continued utilization of TI use into the later portion of the missing persons search, (i.e., the recovery phase) would increase the likelihood of locating the individual (DesMarais, 2014). In research using juvenile pig cadavers (Sus scrofa domesticus) weighing approximately 35-40 pounds was conducted. Despite their size the remains were successfully detected over 114 feet in low-light (night) conditions in a wooded environment during the advanced decay stage. The nonhuman model is has been widely accepted for human decomposition studies (Anderson & VanLaerhoven, 1996) (Grassberger & Frank, 2004) (Komar & Beattie, 1998) (MacAulay, Barr, & Strongman, 2009) (Schoenly & Hall, 2001), the weight range of the juvenile pig cadavers (48-77 pounds) was an appropriate size model for comparison with the size of the average adult human torso (Catts & Goff, 1992) (Sharanowski, Walker, & Anderson, 2008) (Anderson & VanLaerhoven, 1996) (Komar & Beattie, 1998). After death cadavers go through 6 stages of decomposition; as described by Payne (Payne, 1965). The first fresh stage (beginning at the time of death), second bloat stage, third active decay stage (started when there was penetration of the skin by insect larvae), fourth advanced decay stage (started when most of the flesh had been removed from the carcass and the odors of decay began to fade), the fifth dry stage (started when there was only dry skin, cartilage, and bones remaining and insects were still present), and the sixth remains stage (beginning with the absence of all carrion-feeding insects). Complimentary Contributor Copy  Thermal Imaging Cameras in the Detection … 7 During the fresh stage, cadavers undergo algor mortis, a reduction in core body temperature at a rate of approximately 1.5°F per hour beginning at the time of death continuing until ambient temperature is reached (Di Maio & Dana, 1998) (Clark, Worrell, & Pless, 1997) (Dix, Laposata, & Moseley, 1994). Accompanying processes of autolysis and putrefaction span the duration of decomposition from fresh to advanced stages. This overgrowth of bacteria found within the digestive tract can cause a minimal elevation in postmortem body temperature (~0.9F) (Hutchins, 1985), scenarios that would themselves not be detected by TI. However, during this fresh stage in decomposition the insects attracted to cadaveric remains begin colonizing the bodies. The colonization causes an increase in the rate of putrefaction by creating openings in the skin. The openings allow exogenous aerobic bacteria to enter the body and by secreting proteolytic enzymes, which aid in tissue destruction (Zhou & Byard, 2011). The increase in the rate of putrefaction coupled with the increasing heat signatures from the larval masses produces a remarkable amount of heat during this timeframe. While some studies associate the increase in heat from the cadavers to decomposition (Scott, 2016) (Pearson, 2014), the heat signatures from that alone are not great enough to differentiate the body from the surrounding environment effectively. While the insect masses do increase decomposition it is because of the thermal emissions from the larvae themselves that cause such a radical heat difference between the body and the surroundings for the TI to detect (DesMarais, 2014) (Heaton, Moffatt, & Simmons, 2014) (Pearson, 2014). 4. ENTOMOLOGY Blowflies (Diptera: Calliphoridae) in particular are typically the first insect species to arrive at cadaveric remains (Byrd & Castner, 2010). Flies tend to feed on the cadaver and lay eggs typically in the eyes or body orifices; they will also lay eggs in areas of trauma (open wounds) because they are sources rich in nutrients. Complimentary Contributor Copy 8 Angel M. DesMarais At an ambient temperature of 70F, fly larvae will hatch within 23 hours and go through 3 instars or stages of growth, consuming the carcass by scraping the flesh with paired mouth hooks (Castner, 2010). The first instar will typically last 27 hours, the second 22 hours and the third lasts approximately 130 hours. Once the third instar is complete the larvae will migrate away from the body and pupate for a final 143 hours before emerging as an adult fly (Cleveland Museum of Natural History, 2006). As flies are the first to arrive at a cadaver, beetles (Coleoptera: Silphidae) of various genera are the last to leave, as they are primarily predacious and feed on fly larvae (Byrd & Castner, 2010) (Castner, 2010) (Forbes & Dadour, 2010). While TI would not necessarily pick up on the body temperature changes itself after death, it does register the colonization of insect larvae associated with it, and thus can detect throughout the timeframe of this colonization. Fly larvae masses are known to thermoregulate. Small larval colonies (1200 members) can maintain temperatures between 36.5 -57.2F above ambient (Heaton, Moffatt, & Simmons, 2014) (Pearson, 2014). Larger larval masses (2500 or more) have been known to reach temperatures of 122F, the limit at which thermal death occurs (Heaton, Moffatt, & Simmons, 2014) (Pearson, 2014) (Block, Baust, Franks, Johnston, & Bale, 1990). As mentioned previously, a recent study successfully demonstrated the ability of TI to detect cadaveric remains by heat signatures of insect colonization at 114 feet (DesMarais, 2014). In a forested cold climate region in mid-autumn seven juvenile pig carcasses were placed out for study. One of the pig cadavers was selected as a control to test the TI cameras ability to detect heat signatures from decomposition alone, while the remaining six were allowed to be colonized. What was determined was as long as insect larval masses were active and present the heat generated by them was significantly well above ambient temperatures of the surrounding environment. Because of the lack of insect colonization and the colder ambient temperatures, the control expressed very little difference visually from the start to the end of the experiment; in fact after day one TI visualization was nearly indistinguishable from the Complimentary Contributor Copy  Thermal Imaging Cameras in the Detection … 9 surroundings for the length of the study. Despite the occasional frost and dip of temperatures below optimum temperature range for insect activity (50-95°F) it became apparent that as the ambient temperatures rose into the optimum range the larval temperatures too would rise. As they resumed active behavior they again began producing temperatures well above ambient. This cycle continued as long as there was abundant food to support the increased activity, despite decompositional stage. Injuries, size, and health of the individual will dictate the timeframes of not only the duration of the search and rescue, but the length of time and intensity of the colonization and detection by TI. Injuries will allow immediate access for larval masses creating faster colonization, where as it may take two to four days for the larvae to penetrate the flesh, injuries (open wounds) eliminate this delay. Size and health of the body will dictate the length of time for the larval masses to transition the cadaver to the final stages of decomposition. If the individual is small framed the larval colony would be smaller and would exhibit a thermal emission that is smaller in size than that of someone whose frame would accommodate a larger colony. Very small persons would also exhibit a faster decompositional transition thus reducing the timeframe for a TI search. Based on the temperature and visual data collected an optimal time frame can be derived during which TI use would be most successful and subsequent searches could be planned for (Table 1). 5. USE OF THERMAL IMAGING 5.1. Time of Day In general TI detected the greatest thermal emissions (21°F above ambient temperatures) during the advanced decay stage which lasted the longest when larval masses were at their most active, during this stage the cadavers were imaged the clearest from the greatest distances (DesMarais, 2014). Complimentary Contributor Copy 10 Angel M. DesMarais It has been postulated that searches by unmanned aerial vehicles (UAV) during early morning hours would provide the greatest temperature difference between early decompositional heat signatures seen in the abdomen (the site of greatest putrefaction occurs) versus those of the environment (Scott, 2016). However, current studies identified the heat signatures as that of larval masses not decomposition alone (DesMarais, 2014) (Pearson, 2014) (Heaton, Moffatt, & Simmons, 2014). Also as there is a significant cooling of temperatures over the evening hours, larval masses converge to inner cavities to maintain optimum temperatures; as seen in cooler climates when evening temperatures fall below temperatures that are conducive to larval survival. Thus early morning TI use would not be recommended in colder climates during cooler months. Mid-morning to early afternoon TI use would be less than ideal but would extend search time parameters and allow for safer traversing conditions. Imaging during the day can bring challenges as objects in the environment absorb radiant energy throughout the day (Woodworth, Thermal Imaging for the Fire Service, Part 4: Thermal Imaging Devices, 1997), causing a background modeling that can confuse heat signatures of these objects with heat signatures of the insect larval masses. Staff with more experience using TI and ambient signatures during this time frame would have less difficulty (Riker, 2002). Searchers new to TI would be recommended to avoid timeframes of greatest midday temperatures for a few hours afterward. The ideal timeframe for TI search would be a few hours after the greatest midday temperatures (late afternoon/ early evening) into the early evening taking into consideration safety of traversing irregular ground in low-light conditions. During this timeframe the contrast between larval thermal emissions would be radically higher than the surroundings. However heavily shaded locations exhibit less radiant energy signatures allowing for greater larval temperature differentiation and can extend the search timeframe to include much of the day as well as early evening hours. Complimentary Contributor Copy  Thermal Imaging Cameras in the Detection … 11 5.2. Seasons While time of day dictates the optimum ability of TI to differentiate larval mass heat signatures from the surroundings, larval activity is dictated by seasonal temperatures. Temperatures that are too high (>104°F) or are too low (