Estimation method for time to contact from visual information — A simple approach that requires no recognition of objects

Recently, intelligent safety systems for automobiles, such as autonomous collision avoidance, have attracted considerable attention. Usually, automobiles have distance sensors to detect obstacles. On the other hand, animals and insects can behave adaptively, even in an unknown environment, even though they do not have such sensors. In ecological psychology, it is assumed that animals and insects use information related to the time to contact instead of distance information. This time-to-contact information is called the “τ-margin,” and it is calculated from the apparent size of the approaching object and its temporal change in conventional studies. Therefore, the detection of each object is required before calculating the τ-margin. In this paper, we propose an algorithm to estimate the τ-margin without detecting objects. To verify the effectiveness of the proposed algorithm, we conducted experiments using 1/10-scale automobiles and a real vehicle.