Attempt to find optimal selections of EO systems for good results of imaging in real environment surveillance process

In this paper, the authors try to determine a procedure for the best choice in selecting one or other type of sensors as a function of the object under observation, background and environmental conditions. In surveillance activities related with different missions and scenarios occurred in day and/or night time, the proper choice and use of video surveillance sensors is of huge importance. Starting from specific scenarios of surveillance, as for example the surveillance of the sky to detect drones, or surveillance of the ground area to detect some manmade objects or intruders, this paper approaches the problem of the image appearance in VIS, SWIR and LWIR spectral ranges, using different passive technologies of surveillance. Relevant images are comparative presented in relation with some theoretical quantifications made through mathematical models or through software simulations. Starting from a few targets and backgrounds with known spectral reflectivity or emissivity, the contrast was used to show its influence on the signal strength reaching the surface of the video detector (imager) in similar environment conditions. Finally, the authors seek certain characteristics of the electro-optical system itself that can influence most the strength and quality of the optical signal with respect to influences on observation distances of the target. The possibility of using an active technology instead of a passive one, by introducing a pulsed laser illuminator, is also analyzed. The use of some polarizing filters is also considered but in this stage only in laboratory conditions, in order to improve the observability of an object in some special environmental circumstances.