For most of us, the mention of night vision evokes green-hued images from the Gulf War or spy movies, with heavily armed troops stealthily moving in on an enemy, robotic-looking night vision goggles strapped to their heads. Military units have long used night-vision technologies, such as thermal imaging and image intensification, to aid in combat operations. Working with the Federal Emergency Management Agency (FEMA) Technology Support Branch of the Department of Homeland Security (DHS), the Bainbridge Island (Wash.) Police Department (BIPD) learned first-hand how this high-tech, military-developed gear can be an invaluable tool for law enforcement.
Bainbridge Island is a rural bedroom community of Seattle, Wash., approximately 10 miles (via ferry) west of the city. The police patrol consists of 17 commissioned and four reserve officers. Additionally, the BIPD operates a marine patrol unit of one full-time officer with seven part-time officers from the patrol ranks.
The DHS Operational Validation Program was conceived to evaluate equipment in real-world emergency-responder operations. Working with the Operational Validation Program, the BIPD deployed and evaluated two distinctly different types of infrared imaging technology: image intensification and thermal imaging.
How Night Vision Works
Visible light represents a narrow band of wavelengths from 400 nanometers (violet) to 700 nm (red) of the greater electromagnetic spectrum. Thermal-imaging and image-intensified (I2) imaging rely on selected parts of the infrared (IR) spectrum. I2 devices operate in the near IR wavelength, while thermal-imaging devices operate in the middle IR wavelength.
I2 is the most widely adopted technology used in night vision devices. These devices intensify the visual image by amplifying the available light, which allows the user to see in the dark. The process uses an I2 tube comprised of a series of lenses and electrically charged components to increase the available light and form an image. The phosphor elements within the tube produce the green image on the screen that we think of as night vision. The green color is used in these devices because the human eye can distinguish more shades of green than any other color.
I2 devices are used to provide a clear, distinguishable image under dark conditions when there appears to be no available light. Enabling officers to work more effectively and safely, these devices are ideally suited for covert surveillance, search-and-rescue, tactical and navigational operations.
The BIPD deployed and evaluated the PVS-14 Night Vision Monocular from ITT Night Vision. The monocular features a Generation 3 I2 tube with a variable gain control to achieve high-quality image resolution for altering light conditions. Lightweight (12.4 oz.) and versatile, the device can be hand-held, head-mounted, weapons-mounted or camera-adapted. The PVS-14 provides a 40-degree field of view and a typical resolution from 64 72 lp/mm.
Thermal imaging cameras are comprised of four components: a thermal detector, lenses, a video-processing unit and a display. In the thermal detector, the primary component of the camera, thermal energy photons are converted to electrons to create a display of temperatures in the scene. Current technology provides the ability to detect temperature differences as minute as two-tenths of a degree F. The temperature of the object determines the infrared wavelength emitted. Essentially, thermal imagers see the difference, however slight, in temperature between objects. Advances in thermal-imaging technology have resulted in smaller devices with features and performance that apply to law enforcement applications.
Thermal imagers are designed to detect those things that emit or are capable of conducting heat. Because they don t depend on available light, officers can use them during day or night operations, and in absolute darkness. The devices can detect residual heat signatures, making them extremely valuable as investigative tools. Thermal imagers are adeptly suited for search-and-rescue, surveillance and tactical operations because they can detect objects through smoke, fog, dust, rain and light foliage. Additionally, many current devices can record the images to use as evidence.
The BIPD evaluated FLIR Systems ThermoVision FlashSight thermal-imaging device. The FlashSight is a lightweight (1.9-lb.), rugged, hand-held thermal imager, featuring instant-on imaging, reverse polarity, automatic brightness control and a bellows eyecup for covert operation. Equipped with a 160x120 VOx microbolometer long-wave thermal imaging sensor, the FlashSight provides a 30mm, 13x10-degree field of view. The unit saves up to 70 still images to internal storage for download through a USB cable, and displays live video on a standard TV monitor. It operates at temperatures from 26 131 degrees F.
Law enforcement agencies can use thermal imaging and I2 devices in a broad scope of applications where enhanced vision in darkness proves useful and provides a dramatic advantage to the operation at hand. As mentioned above, I2 devices provide the ability to capture images with very little ambient light and provide enough clarity to identify specific characteristics and details of a scene. Thermal imaging devices can be used during day or night, without any ambient light, and can detect activity in a variety of environmental conditions.
In patrol scenarios with the marine and land-patrol units, the BIPD made valuable use of I2 technology. From the patrol boat, the marine unit employed a non-visible infrared laser to mark on-shore targets for land-based officers who patrolled in the area using the PVS-14 night vision monocular. The devices provided an effective combination for surveillance in an area that proves typically hard to patrol.
Also using the I2 night-vision device, the BIPD assisted with the apprehension of a woman who had a history of mental illness and had been known to possess a firearm. When officers attempted to arrest her during a previous incident, she had resisted arrest and assaulted the arresting officer.
The BIPD officers used the PVS-14 monocular to monitor the woman s behavior from an undetected, safe distance. The officers determined the best time to enter the home, the safest entry point and whether the suspect was armed details that would have been time-consuming or impossible to gather without the assistance of the night-vision monocular.
The BIPD marine unit used the PVS-14 monocular to navigate the waters around the island. The device s head mount enabled hands-free operation, which permitted the boat operator to use the equipment rather than depending on an additional officer to work as a spotter. The single-eyepiece design allowed the operator to view the boat s radar while wearing the device.
A marine unit officer deployed the PVS-14 during a tactical training exercise with local, state and federal tactical teams and the Washington State Ferry System (WSF). The WSF is the largest ferry system in the United States, operating 28 vessels. The ferries shuttling between Seattle and Bainbridge Island hold a maximum of 2,500 passengers, 218 private vehicles and 60 commercial vehicles.
One of the training exercises required officers to stand watch during underway boarding onto the rear of the ferry. Three officers aboard the safety boat were assigned to watch and rescue anyone that fell into the water. The temperature of Puget Sound that evening was 54-degrees F, making quick detection and reaction critical. During this exercise, we were able to maintain excellent situational awareness [with the thermal imager], says BIPD Lieutenant Bob Day. And if one of the tactical guys went into the water, we would ve been able to get to them in no time flat.
During the exercise, the boat ventured into an area that contained a large number of logs due to high tidal activity. The other problem in this exercise was the number of deadheads in the water, Day says. It was a challenge to avoid hitting them. The boat operator used the night-vision monocular to navigate around obstacles.
Search & Rescue
During the evaluation period, the BIPD used the FlashSight thermal imager in a life saving search-and-rescue incident. While on patrol, a lieutenant was flagged down close to midnight by some men in a residential neighborhood. The men reported they d heard someone yelling for help. The temperature that evening dipped below 40-degrees F. Several more officers were called to the scene to assist with the search.
Using the FlashSight thermal imager, a patrol officer located the victim in approximately 15 seconds. She was found lying face-down and unconscious, having fallen approximately 10 feet from the rear deck of a house. The fire department arrived and assumed care for the woman. The victim was transported to a local hospital for treatment of a head injury. She was diagnosed with an intracranial bleed and airlifted to a trauma center in Seattle, where more injuries were diagnosed.
The officer who used the FlashSight attributed the quick find to the thermal imager, which provided enhanced search capability over the use of a traditional flashlight. The area was dark and densely wooded with leaves and debris on the ground. The thermal imager allowed the officer to quickly scan the area and get a reading of the heat generated from the victim s body. If this was handled as a traditional search and rescue, we would ve had to get a lot of folks out to search the area for the victim, Day says. The FlashSight turned out to be a force multiplier, allowing a single officer to keep eyes on a wider area and find the victim.
By the time the officers located the victim, she was unconscious and unable to call for help. The officers say that if they had used traditional search means, they might have missed her, and she might have died from her injuries. BIPD Officer Christian Hemion says, The thermal imager allowed us to quickly locate the victim and speed up the process of getting her medical care. The equipment definitely made a huge difference in her survival.
The BIPD used the thermal-imaging equipment in several investigations. Many of these incidents involved suspects who fled into overgrown areas in an attempt to avoid apprehension. On one occasion, the FlashSight thermal imager s ability to locate heat signatures not only allowed the investigating officers to apprehend a suspect hiding in dense undergrowth, but also to quickly locate his discarded stash of marijuana nearby the packaging was still emitting heat from where it had been recently handled.
The BIPD determined the infrared imaging technology found in image intensifiers and thermal imagers improved the department s overall situational awareness, which translated directly to measurable improvements in most aspects of its operational tasks. The addition of the image intensifiers and thermal imaging technology:
In short, night-vision technology provided BIPD officers with numerous strategic advantages, making their jobs safer and more effective.
For More Information
Bainbridge Island Police Department
625 Winslow Way East
Bainbridge Island, WA 98110
E-mail: Lieutenant Bob Day at
United States Department of Homeland Security (DHS)
System Assessment & Validation for Emergency Responders (SAVER)
The DHS s SAVER Program assists emergency responders in making procurement decisions. The SAVER Program conducts unbiased operational tests on commercial equipment and systems, and provides those results along with other relevant equipment information in an operationally useful form.Tel: 877/347-3371
Operational Validation Program
The Operational Validation Branch of the SAVER Program works to place equipment in the hands of the emergency responder and conduct follow-up evaluation of the equipments impact and usefulness in meeting operational requirements of the emergency responder community.
E-mail: Michael Besco at email@example.com
or Danny Heater at firstname.lastname@example.org
Vendor Contact info:
FLIR Systems, Inc.
27700A SW Parkway Ave.
Wilsonville, OR 97070
ITT Night Vision
7635 Plantation Road
Roanoke, VA 24019