Abstract: Automatic vehicle number plate recognition is a challenging task and becoming important area of research due to its difficult applications such as Traffic data collection, toll collection, crime prevention and security control of restricted areas. Therefore in the last few decades many efforts were taken by researchers to develop different techniques for thresholding and segmentation of the vehicle number plate. This review presents many basic and advanced adaptive thresholding techniques for automatic vehicle number plate recognition.

Keywords: Adaptive thresholding, Integral image, mean, median, Gaussian filter.