Identification of Brain Tumor using Neural Network and Support Vector Machine Bhawna Gupta, Shamik Tiwari CSE, Mody University of Technology & Science, India Abstract: Brain tumor is one of the deliberate diseases, causes death among the peopl e. Imaging techniques like CT scan (Computed Tomography) and MRI (Magnetic Resonance Images) are used for diagnosis the brain tumor. Here in this paper a computer based system is designed for the detection of brain tumor from the MRI images. This system consists following steps feature extraction and classification. The extraction of features from the MRI images has been achieved by curvelet transform. Then these extracted features are employed in neural network and support vector machine respectively. This system gives efficient accuracy in the detection of brain tumor. Keywords: Brain Tumor, Curvelet Transform, Neural Network, Support Vector Machine I Introduction Medical imaging is an active research area in image processing which is play crucible role in the detection of brain tumor. The motivation of medical imaging provides information about the human system and this information is used by doctor to detect the diseases[1].Medical imaging provides many techniques like MRI (Magnetic Resonance Imaging), CT scan (Computed Tomography), and MRA (Magnetic Resonance Angiography) for diagnosis of brain tumor [2]. From these techniques, MRI is a most efficient technique for the detection of brain tumor because it doesn’t use x rays and it provides high resolution images of soft tissues [3]. But due to the shortest of radiologist and large volume MRI data to be analyzed makes it cost expensive and labor intensive. So there is need a computer based system which classify medical images accurately [4]. Image processing techniques are used for designing the computer based system. Various author used image processing techniques for the detection of brain tumor. Some of discussed below. Joshi et al. [5] developed a classification system. The main stages of this system are, first tumor segmentation done by histogram equalization, second feature extraction, gray level co- occurrence matrix is used for this approach. Then classification is done by neuro fuzzy classifier. Texture features are used in the training of the artificial neural network. Gupta et al. [6] proposed a technique in which feature extraction is done using curvelet transform, then these features are applied to support vector machine for successful classification. Sridhar et al. [7] recommend a technique which follows two steps process in first step dimensionality reduction and feature extraction which is done by discrete cosine transform and second step is classification done by probabilistic neural network. The rest paper is organized as follows section II describe the proposed methodology. Section III describes the experimental results and conclusion describe in section IV. II Methodology In our proposed method we use two classifiers for the detection of brain tumor. The whole procedure shows in the flow chart. Apply Curvelet transform Input Image Curvelet Decomposition Feature Extraction Mean and Standard Deviation Neural Network Classification Cancerous or not cancerous Support vector Machine Result Fig1 Schematic diagram of Proposed Methodology Figure 1 shows the procedure of proposed method. It incorporates three steps i) Input Database ii) Feature Extraction iii) Classification. Feature extraction extracted the features of MRI and classification classify brain MRI is cancerous or non cancerous. Fig 2 Implementation of fast digital curvelet transform 2.1 Input database: The input data of our project is MRI (Magnetic Resonance Images) images. These data are taken from TCIA (The Cancer Imaging Archive) [8]. From the TCIA database we selected 50 MRI images in which 25 are cancerous and other 25 are non cancerous. The size of images is 512x512. The implementation of FDCT to an image in wrapping version follows the following procedure [11]. i) The 2d image first converted into the frequency domain by applying the Fourier transform. 2.2 Feature Extraction: Feature extraction defines the relevant features that are used for understanding the image. Classification depends on the feature extraction process. In our system feature are extracted using curvelet transform. 1) Curvelet Transform Candes et.al [9] developed a new multiscale transform which represent curve singularities along the edges much more efficiently than the other transform, is known as curvelet transform. In 2006, the initial construction of curvelet transform was redesigned and then it was later introduced as fast digital curvelet transform (FDCT). This method is easy to understand in comparison to the first method. Curvelet transform is defined in both forms like in continuous and digital. Image based feature extraction is done by FDCT. There are two types of digital implementations of FDCT: i) Curvelets via USFFT (Unequally Spaced Fast Fourier Transform) and Curvelets via wrapping [10]. Both take Cartesian array as an input and produces digital coefficients as an output. Image in Fourier Domain 2d image ii) Then the transformed image convoluted with the set of window function. The shapes of window function are according to the requirements of the ideal curvelet transform like parabolic scaling law. iii) Now inverse Fourier transform (IFFT) is applied for curvelet coefficient. But due to the frequency response of curvelet is non rectangular wedge, for IFFT wedge must be in rectangular form. So wrapping is done. iv) After wrapping, IFFT is applied and curvelet coefficients are obtained. At scale 1 one sub band image Scale 2 eight sub band images Apply Curvelet Transform Scale 3 sixteen sub band images FFT Product of image with curvelet window Scale 4 sixteen sub band images Wrapping IFFT Curvelet Coefficients Fig 3 Curvelet Coefficients at varied angles (scale=4) Curvelet coefficient in Fourier domain Figure 3 shows the schematic diagram of a proposed MRI features extraction. At every scale and from each sub band images we computed two features (Mean and standard deviation). So we get total 82 features. Now these extracted features are employed into both classifiers. 2.3 Classification 2) Support Vector Machine: Classification means to classify between the cancerous and non cancerous images. In our proposed work we used two classifiers i) Neural Network ii) Support Vector Machine. Extracted features are fed up into both classifiers. In 1992 a new learning process is developed by Vapnik which known Support Vector Machine (SVM) [13]. SVM provides higher accuracy in terms of data classification and other data classification algorithms. So it is used in many applications like text categorization, hand-written digit recognition, tone recognition, image classification and object detection, micro-array gene expression data analysis, data classification [14]. The concept behind SVM is finding the optimal hyperplane that separates the classes and has maximum distance between both classes. Artificial neural network is a simplified model of the brain and also referred as neural network. It is made up of biological neurons that are connected together and forms a network. A particular weight is associated to each neuron. It resembles brain in two aspects [12].i.) Knowledge is acquired by the network through the learning process. ii.) Interneuron connection strength known as synaptic weight, one used to store this acquired knowledge. Wi1 Summing Junction X1 Wi X2 ∑ 2 Activation Function Xn Wi3 Inputs F y Optimal Hyperplane Feature of class2 1) Artificial Neural Network Output bk Synaptic weights Bias Fig 3 Basic Neuron Model Feature of class1 The block diagram of figure 3 shows the basic neuron model. Three basic elements of neural network are Fig 4 A linear classifier Input: Each input is associated with a numeric weight An adder is there which is used for summing the inputs. Activation function, which is used to limit the amplitude of the output of a neuron. The output of a neuron is a function of the weighted sum of the inputs plus a bias. Bias is a fixed input. yi = f ( ∑𝑗=0 𝑤 ij xj ) + bk (1) Neural network is used for solving the variety of problems like classification, segmentation etc. Figure 4 shows the example of linear two class classifier. Here we have two classes’ cancerous and non cancerous. There is a number of hyperplanes that separates the both classes. So SVM find optimal hyperplane which have maximum distance between both classes and no points between them. SVM works on maximum margin principle. III Results As explained earlier 50 images are selected from the database out of which 25 are cancerous and 25 are not cancerous. We have used all the images for training and testing of classification framework. We used 30 images for training and all images are used for testing. In both classifiers positive samples (cancerous MRI) are trained by 1 and negative samples (Non cancerous MRI) by 0. To estimate the performance of both classifiers we calculate accuracy (AC), precision (P) and recall (R) of each classifier. Accuracy defines how many samples are correctly classified. Precision is the percentage of the samples which actually have cancerous class with all those which were classified as cancerous class. Recall is the percentage of the samples which were classified as cancerous class, with all samples which truly have cancerous class. AC= (TP+TN)/ (TP+TN+FP+FN)*100 (2) P = TP/TP+FP*100 (3) R= TP/TP+FN*100 (4) draw between the true positive rate (TPR) and false positive rate. In ROC the diagonal line shows the random classification, if curve is draw above the diagonal line it shows better classification. Where TP is the number of true positives, TN is the number of true negatives, FN is the number of false negatives, and FP is the number of false positives, are defined as: TP: Predicts cancerous as cancerous. Fig 5 ROC Curve for SVM TN: Predicts noncancerous as noncancerous. FN: Predicts cancerous as noncancerous. FP: Predicts noncancerous as cancerous. ROC for Support vector machine is shown in figure 5. In this curve blue line depicts the performance of the classifier. This curve is draw above the diagonal shows the good classification. Performance of Neural Network Accuracy 94.00% Precision 100% Recall 89.28 Table 1 Performance of Neural Network Table 1 shows the results after testing the neural network with all images. Performance of Support Vector Machine Accuracy 98.00% Precision 96.15% Recall 100% Table 2 Performance of Support Vector Machine Fig 6 ROC Curve for NN Table 2 shows the results after testing the neural network with all images. According to the tables support vector machine gives better results than the neural network. ROC Curve ROC curve (Receiver Operating Characteristics) demonstrates the performance of the classifier. It is ROC for Neural Network is shown in figure 6. In this curve blue line depicts the performance of the classifier. According to the ROC curve of both classifier support vector machine give better classification than the neural network. IV Conclusion A computer based method has been developed for classify the brain tumor using image processing techniques. The main steps of this system are feature extraction which us done by curvelet transform. For the classification task we used two classifier1) neural network 2) support vector machine. From the results it is found that support vector machine gives better classification in comparison to neural network. In this technique classification is done between the cancerous and non cancerous images. In future this technique makes more advances then tumor is classified according to its type. References [1] M. G. Mostafa and M. F. Tolba, Medical Image Segmentation Using Wavelet Based Multi resolution EM Algorithm, IEEE trans on Industrial Electronics, Technology and automation, IETA, 2001. [2]Mubashir Ahmad, Mahmood ul-Hassan, Imran Shafi, Abdelrahman Osman,"Classification of Tumors in Human Brain MRI using Wavelet and Support Vector Machine",in IOSR Journal of Computer Engineering(2012) [3] Islam, Atiq, Syed Reza, and K. Iftekharuddin. 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