The invention provides a bag-of-
word model based
vehicle type identification method for an unlicensed vehicle at a gate. The method comprises: firstly, finishing
vehicle detection based on a
histogram; finishing vehicle face positioning based on gradient density; performing
vehicle type classification based on a bag-of-
word model, which comprises two parts of training and testing; and for the problem of poor classification effect caused by correlation of throwaway vocabularies of the bag-of-
word model, constructing spatial information. When the spatial information is constructed, the spatial information is divided into two parts of global spatial information and local spatial information to perform calculation, wherein the global spatial information is obtained from a spatial angle relationship between image blocks with the same marks; the image blocks, with the same marks, of an image are sorted according to distances between the image blocks and an origin first, included angles between two adjacent image blocks and a
horizontal axis are calculated in sequence, and global angle
histogram information about each mark is subjected to statistics; and for the local information, a local frequency
histogram of occurrence of the blocks with the same marks is calculated with a specific method. The histograms of the
global information and the local information are combined to finish the construction of the bag-of-word spatial information. The method is relatively high in accuracy, has relatively low vehicle face positioning requirements in positioning accuracy, is short in
running time, and can meet general application requirements.