This section presents a possible solution to the problem of lane detection in images acquired from a camera installed on a mobile vehicle which is reduced to the detection of lane markings. In this case the a-priori knowledge exploited by the IMP transform is the assumption of a flat road in front of the vehicle. The advantage offered by the use of the IPM is that in the remapped image (see figure 2.c) the road markings width is almost invariant within the whole image. This simplifies the following detection steps and allows its implementation with a traditional pattern matching technique on a SIMD system.
The basic assumption lane detection relies on is that road markings after the IPM transform are represented by quasi-vertical constant width lines, brighter than their surrounding region. Hence the first step of road markings detection is a low-level processing aimed to detect the pixels that have a higher brightness value than their horizontal neighbors at a given distance. The following processing is in charge of the reconstruction of the road geometry.
Figure 2: IPM applied to a road environment: (a) 3D representation of the environment, (b) the acquired image, (c) the remapped image