August 2015

Working characteristics of thermal cameras are very different from those of conventional cameras. The image of a thermal camera is monochrome and is a representation of relative temperature of objects.

A person or an animal is visible in a thermal image in as much as their temperature is different from the temperature of the background. The contrast in the thermal image can be very different depending on time of day or weather conditions. For example, in an outdoor scene of a cold night, a pedestrian will appear white of light color on a black or dark background. However, in the same scene during a sunny day, the pedestrian walking on hot asphalt will appear black (or dark) on a white or light grey background.

The OneTrack intelligent detection functions work very well with thermal cameras since all is needed for a good detection is a good contrast between objects and the background. The thermal sensitivity becomes especially useful for outdoor surveillance under very low light conditions.

For alarm central monitoring, OneTrack intelligent detection coupled with thermal camera can result in excellent sensitivity with very low false detection. In addition to sending messages to a control stations, alarms can be sent email or to a private monitoring station based on VideoWave’s CMS software.

In a general context, let’s say it is desired to monitor an outdoor area with a PTZ camera and a fixe camera. If the fixe camera is used to detect objects and the PTZ to track them, then in night (low light) condition a conventional fixe camera will not have the excellent contrasted image of the objects that a thermal camera provides and thus the tracking of objects will not be as good as with a thermal camera.

Until recently, the high cost of thermal cameras restricted their usage in many commercial applications. However, new models have been brought to market recently that expand the possibilities for these applications.

We have tested several models from FLIR and have conclude that the new models with very low resolution (80, 45) still deliver good results, when used as detection, not as view image.