One of the goals of the whole project was the development of a low-cost system, in order to ease its integration on a large number of vehicles. This design choice led to the use of low-cost devices such as videophone cameras (small sized 3.5 cm x 3.5 cm sensors of the approximate cost of 100 USD).
Although having a high sensibility even in low illumination conditions (such as during the night), a quick change in the illumination of the scene causes a degradation in the image quality (for example at the entrance or exit from a tunnel). In particular, having a slow automatic gain control (they have been designed for constant illumination applications such as video-telephony), at the exit from a tunnel for about 100200 ms the acquired images are completely saturated and the analysis becomes impossible. The possible solution to this problem is the use of cameras with higher performance and, in particular, with a faster automatic gain control and with higher dynamics.
On the contrary, the resolution of these devices turned out to be satisfactory and the framing of the scene (no horizon to reduce strong light conditions) correct for the type of roads considered.