Thermal Sentry

Summary of Features...

ThermalSentry™ is a high-accuracy, non-contact, area coverage, body temperature monitoring system targeted at real time detection of S.A.R.S. and influenza victims including Swine Flu. It remotely measures the skin temperature of subjects at distances up to 10 meters. All subjects in the field of view are monitored simultaneously so there is no need for people to queue in order to have their temperature recorded. The system continuously self calibrates using two high accuracy thermally controlled targets (blackbodies) for maximum detection capability with minimum false alarms. If all subjects are below the user settable alarm point, a green light is activated. If one or more subjects have a skin temperature above the set point, a red light and audible alarm are switched on. In addition, the over temperature area is outlined in red and displayed on the computer monitor. All alarm conditions are recorded for later review to identify the particular subject that caused the alarm condition.


 

Standard Configuration...

  • Coherix ThermalSentry™ software featuring:
    • Integrated digital video recorder
    • Pseudo color, grayscale and over temperature displays
    • Programmable alarm set points
    • Up to 10 separate monitoring windows per field of view
    • Opto22 alarm outputs
    • Continuous monitoring, or inspect-on-demand
  • Thermal imaging sensor
  • 22" LCD All-In-One Touch Screen Computer
  • Dual high accuracy temperature calibration references (blackbodies)
  • Color video camera
  • Heavy-duty tripod with manual pan/tilt head
  • Status / alert lights and audible signal

Optional components:

  • Motorized pan/tilt head
  • High speed infrared camera


ThermalSentry™ integrates all of these components into a portable, unobtrusive, and easy-to-maintain system. The dual temperature references, alert lights, and audible alarm are housed in a sleek white tower or wall unit. The thermal imaging and video cameras are housed in a protective enclosure mounted on a heavy-duty tripod. The camera unit can also be wall or ceiling mounted. The All-In-One touch screen computer can be wall mounted, enclosed in a portable cart, or simply placed on a desk. All components communicate over any standard Ethernet network. The calibration tower and camera tripod fold up for portability (see following diagram).


Multiple ThermalSentry™ systems can be linked together on a network and monitored from a central location.

The various components of the ThermalSentry™ system can be purchased separately and integrated into existing equipment (e.g. metal detectors, turnstiles, doorways, etc.).

 

Operation...

As subjects pass by the tower (or wall unit), the thermal imaging and video cameras acquire their image. The subjects and the temperature references are captured in the same Field Of View (FOV) at a rate between 5 and 60 images per second (depending on options). The temperature references are monitored and maintained within +/- 0.03 ºC of their set points. This allows the ThermalSentry™ system to automatically calibrate itself in real-time for maximum accuracy and detection capability.

The video image is used for subject identification. Because it is nearly impossible for a novice to recognize facial features in a thermal image, it is important to have a video image of the subject that can be referenced to the thermal image.

If one or more of the subjects in the FOV are above the user settable temperature, a red warning light is flashed on the tower and the audible alert is activated. This allows the ThermalSentry™ system to run unattended until an alarm condition is detected. A brief video clip (duration user settable) of both the thermal and video images is stored for each alarm condition. This allows the operator to review the event and identify the cause of the alarm. The operator can also elect to record video at any time for archival and training purposes.

   


Accuracy...

The accuracy of ThermalSentry™ is +/- 0.25°C measuring temperatures between 25 and 40°C at distances between 5 and 10 meters. The accuracy was tested and verified at Taiwan's Industrial Technological Research Institute (ITRI) in May of 2003. This accuracy is an order of magnitude better than most "industrial" thermal imagers. These industrial imagers are internally calibrated (radiometric) and are often in a camcorder format. They were designed for predictive maintenance and process control applications. However, their real-world accuracy is on the order of +/- 2°C which is fine for predictive maintenance, but far too inaccurate to discriminate between a normal subject at 37°C and a feverish one at 38°C.

ThermalSentry™ was designed from the ground up to be a high-accuracy body temperature measurement system. It is not a process control system that was hastily pressed into service performing a job for which it was not designed.

Below are screen shots taken on June 23, 2003 at Hsinchu Hospital in Taiwan, during field testing. The image on the top shows a pseudo-color image of a feverish child being carried by a woman. The image in the middle shows the over temperature alarm, and highlights the child as having a fever. The image on the bottom shows the image recorded by the CCD camera for identification purposes. Note the calibration tower in the right hand portion of the images.