Development of inter-vehicle distance measurement system using camera-equipped portable device

In this research, an inter-vehicle distance measurement application that runs on Android operating system was developed. The proposed method was based on a similarity relationship between the license plate and the image on the image sensor. Morphological transformation was implemented to improve the detection rate of the license plate and distance measurement accuracy. Although the maximum error rate of the measured distance was 12 % at a distance from 2 m to 15 m, it is possible to reduce the value of the error rate by increasing the resolution of the captured image. The processing time for one cycle was 185 ms, and the processing time for each processing of this application was also measured. As a result, 46.5 % of the whole process was occupied by morphological transformation. However, by applying morphological transformation to only a part of the image, it is possible to reduce processing time of this processing.