An Approach for Automatic Recognition System for Indian Vehicles Numbers Using K-Nearest Neighbours and Decision Tree Classifier^
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International Journal of Advanced Science and Technology Vol. 28, No. 9, (2019), pp. 477-492 An Approach for Automatic Recognition System for Indian Vehicles Numbers Using K-Nearest Neighbours and Decision Tree Classifier^ Ruchika Bindal1, Pradeepta Kumar Sarangi1*, Gagandeep Kaur1, Gamini Dhiman1 1Chitkara University Institute of Engineering and Technology Chitkara University, Punjab, India Abstract An Automatic Vehicle Number Plate Recognition System is presented in this paper. Basically, there are different kinds of motor vehicle number plates which are used in India. The actual number plates are not similar and most of them are deviated from the prescribed norms as laid by Government of India from time to time. The number plates of Indian vehicles are written in different languages also. The number plate characters are varied according to the language of a particular state in the country however a large portion of number plates are written in English language (legally all plates are required to be in modern Hindu-Arabic numerals with Latin letters). This is very vital in recognizing the number plates, extraction of number plate characters, segmenting the characters because of some diversity. In this paper we present a work on extraction of number plates, segmentation and recognition of number plates in the domain of English language. Prewitt filter technology is used for extracting the number plate thresholding and for segmentation of connected component analysis are used. For recognizing the characters, neural network, k-nearest neighbor and decision tree classifiers are used. The recognition rate of neural network is 96.1%, k-nearest neighbor is 95.55% and decision tree is 91.38% respectively which is acceptable for future research in this direction. Keywords— Indian Vehicle Number Plate, Pattern Recognition, k-Nearest Neighbor, Decision Tree, Neural Network, Local Histogram, Hierarchical Centroid. 1. INTRODUCTION Automatic Vehicle Number Plate Recognition (AVNPR) system [1] is an essential technique that is used in intelligent systems like transportation systems. Actually, this system uses the progressive technology of machine vision that uses the number plate of vehicles without any straight forward interference of humans. Because of its many applications, this is an important area for research work. The evolution of the intelligent systems basically provided from the data of number plates of the vehicles that can be used for further reasoning and supervising. Basically, there are many important areas where the AVNPR is used such as in traffic problems for collecting the tolls on highway, for security at borders and customs where there is a need of high security in the premises and so on, when the number plate is standard then the AVNPR system will not have any ISSN: 2005-4238 IJAST 477 Copyright ⓒ 2019 SERSC International Journal of Advanced Science and Technology Vol. 28, No. 9, (2019), pp. 477-492 difficulty for reading and recognizing the number plate. As we see that in India there are different models of number plates so it is difficult task in India. The work of AVNPR is generally wrapped into the following steps: Extract the region of interest of a number plate, segment characters and recognizing characters followed by the generation of a string which contains the actual characters in the number plate of a vehicle. The system captured the image of vehicle which is treated as input image from where the only area of number plate is observed and that can be used in further processing. In next step, segmentation of characters are done. In this, every character is segregated and disjointed. The character recognition is done on the basis of choice of the characters of outstanding features by using a recognition engine. 2. LITERATURE SURVEY In (Parasuraman, et al, 2010) [2], the method proposed is for the recognition of Indian number plates. Image is the only input for the system which is acquired by a camera. This method consists of following stages: RGB or colored to gray scale conversion, detection of vertical edges and binarization of image, analysis and dilation of image, vertical projection and thresholding, extraction of actual location of the number plate, apply filters and enhancing the image, binarization and smoothing process and segmentation of characters for horizontal and vertical division. In this method, the speedup is achieved in processing. The colored images are converted to the gray scale images based on RGB to gray scale conversion technique. Then the resulted images are converted to the binary images. Binarization is done to extract the number plate region from the acquired image [3]. The filtration is used to remove the unnecessary objects from the number plate. In analysis, it looks for the appropriate size of image, it calculates the values of height and the width. There are certain fixed height values, that is, maximum height and minimum height. If the object height is in the range then the object is retained and otherwise it removes other object. After that there are fixed width values for maximum and minimum width. If the object is in the width limit then the object is retained otherwise it removes other objects. The process of dilation is used to get the rough location of the number plates. After getting the accurate location, the extract and only required region of the number plate from which the starting and ending position of the number plates are identified. In (Du. et al., 2013) [4] in the recognition system of license plate shows the accuracy of ALPR system. They employed various techniques for license plate extraction. A. Using Boundary/Edge information As the number plates are usually in rectangular shape with a known aspect ratio, it can extract the number plate from all the rectangles that are in the image. It uses the Sobel filters as used to detect the edges. As there is the difference in color of car body and number plate, so the boundaries of number plate are shown by the edges. The outcome of this method yields 96.2% on images under the various conditions. B. Using global image information The Connected Component Analysis (CCA) technique is used in binary image processing. It scans the binary image and the pixels of the image are labeled into components that are based on pixel connectivity. C. Using Texture Features ISSN: 2005-4238 IJAST 478 Copyright ⓒ 2019 SERSC International Journal of Advanced Science and Technology Vol. 28, No. 9, (2019), pp. 477-492 This method depends on the text or the characters that are present on the number plate, which results the difference in gray scale level between the colors of the characters and the background color of the number plate. D. Using color feature Some countries have the specific color for their number plates. By this, the number can be extracted from the image by locating their respective color. According to (Rajput and Som, 2015) [5] the method followed have three phases: image capture, license plate localization and number recognition. In image capture phase, the captured image of the vehicle is normalized. The standard dimension to normalize an image is 400 x 300 pixels. Then the image is converted to the gray scale. In plate localization phase, the wavelet decomposition is performed to get the approximation. The number plate is located by the vertical and horizontal frequency energies. A Gaussian filter is used to modify the incoming signal with a Gaussian function. There are many benefits for using the Gaussian filter as it is rationally symmetric, there is decrease in variation of filter weights from the central peak; the central pixels have the highest weight, this filtering is separable, this means that the filters rotate the image with 1D horizontal filter and after that convolves it with 1D vertical filter. In the number plate recognition phase, to get the number plate the gray colored image, the image are converted into black and white image and sets the pixels intensity in the range of 0 and 255. After segmentation, the characters are normalized for refinement for no extra white pixels. In (Ram Lingam. et al., 2014) [6], the report is based on UK number plates and the misread plates. There are some defined parameters: A. Failed to capture and misreads The automatic number plate recognition system is failed to get the picture from the camera when the vehicle is passing. The "misread" is that when the OCR engine has failed to read the number plate correctly. B. Character spacing analysis from police data There are records of the images that are captured, some of them are legal and some are illegal. Illegal number plates are those which have illegal fonts, spacing. So, these numbers are analyzed from the police data. C. Character spacing Analysis from real world data In this, they have data from the real world that is they experimented with 2,200 number plates which were photographed by a digital camera. They have taken the data of two major airport car parking and send them to the police for safety to check them randomly and get the proportion of legal number plates and the number plate that have the illegal fonts. In the report, for the first time the vehicle number plate image is standardized (Chi et al., 2006) [7]. Scaling and again evaluation are tested for erasing the exception and ascertain clear specifications for SVM process. For character recognition, the SVM process has been used. SVM process have higher correct detection rate than the neural network systems. ISSN: 2005-4238 IJAST 479 Copyright ⓒ 2019 SERSC International Journal of Advanced Science and Technology Vol. 28, No. 9, (2019), pp. 477-492 In (Lopez. et al., 2007) [8] designed a system which is suitable in when the camera is in motion.