An exponential increase in number of vehicles necessitates the use of automated systems to maintain vehicle information. The information is highly required for both management of traffic as well as reduction of crime. Number plate recognition is an effective way for automatic vehicle identification. Some of the existing algorithms based on the principle of learning takes a lot of time and expertise before delivering satisfactory results but even then lacks in accuracy. In the proposed algorithm an efficient method for recognition for Indian vehicle number plates has been devised. The algorithm aims at addressing the problems of scaling and recognition of position of characters with a good accuracy rate of 98.07%. Efficient Method to Number Plate Recognition Using Template Matching
In detection of number plate area, firstly dilation operation is applied on sobel edge detected image and after this holes are filled by using MATLAB function. Then morphological opening and erode operations are used for exact detection of candidate plate area
The mask is slid over an area of the input image, changes that pixel’s value and then shifts one pixel to the right and continues to the right until it reaches the end of a row. It then starts at the beginning of the next row. The example below shows the mask being slid over the top left portion of the input image represented by the green outline. The formula shows how a particular pixel in the output image would be calculated. The center of the mask is placed over the pixel you are manipulating in the image. And the I & J values are used to move the file pointer so you can mulitply, for example, pixel (a22) by the corresponding mask value (m22). It is important to notice that pixels in the first and last rows, as well as the first and last columns cannot be manipulated by a 3×3 mask. This is because when placing the center of the mask over a pixel in the first row (for example), the mask will be outside the image boundaries.