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Advances in Natural and Applied Sciences, 9(7) June 2015, Pages: 92-99 AENSI Journals Advances in Natural and Applied Sciences ISSN:1995-0772 EISSN: 1998-1090 Journal home page: www.aensiweb.com/ANAS Unsupervised Segmentation based Classification of MICROCALCIFICATION Using SVM S. Venkata Lakshmi and Dr. J. Janet CSE Manonmaniam Sundaranar University, Tirunelveli ARTICLE INFO Article history: Received 12 March 2015 Accepted 28 April 2015 Available online 1 June 2015 Keywords: breast Cancer, Features, classification, Particle swarm optimization. Fuzzy Enhancement. ABSTRACT Advancement of medical image digitalization leads to image processing and computeraided diagnosis systems in numerous clinical applications. These technologies could be used to automatically diagnose patient or serve as second opinion to pathologists. This paper briefly reviewed on breast screening techniques, available, so that this can motivate the researcher to concentrate more on medical related issues which becomes a small contribution to our country which is very essential. The digital data of the screening techniques are used as data for the computer screening system, as replaced in the expert analysis. Four stages of the computer system are enhancement, features extraction, feature selection, and classification reviewed in detail. Breast cancer takes a tremendous toll on women, next to skin cancer; it is the most common cancer in women and the leading cause of mortality in women. Screening program is based on x-ray examination of the breasts which is the best method for early detection. The development of the new system is to assist the radiologist and not to replace the radiologist. The proposed system consists of three stages namely image enhancement, segmentation and classification of micro calcification. Enhancement of mammograms is done by normalization, noise removal and pectoral muscle suppression to improve the quality of the image and in separating the pectoral muscle from the whole breast area. Detection of suspicious regions is done by segmentation. In this Particle Swarm Optimization (PSO) has been proposed to segment the suspicious regions from the enhanced image. Classification is done in three steps namely feature extraction, feature selection and by classification in two phases. Features are extracted from energy values which are calculated from wavelet transform of an image. Support Vector Machine (SVM) is used as a classifier, which classifies the micro calcification into benign and malignant. SVM improves classification accuracy. The classifier proved to possess the best recognition ability due to its ability to deal with nonlinearly separable data sets. Receiver Operating Characteristic (ROC) analysis is presented to evaluate the classification performances with Darwinin PSO (DPSO) and FODPSO. Micro calcification images in the Mammography Image Analysis society (MIAS) database are used to evaluate the proposed system. © 2015 AENSI Publisher All rights reserved. To Cite This Article: S. Venkata Lakshmi and Dr. J. Janet, Unsupervised Segmentation based Classification of MICROCALCIFICATION Using SVM. Adv. in Nat. Appl. Sci., 9(7): 92-99, 2015 INTRODUCTION Cancer is the public health problem for men and women in this century. According to the survey more than 8% of women are affected by breast cancer (Jemal, 2008; Imaginis Corporation, 2008) and 29% of men are affected by prostate cancer (Ferlay, 2007; Jemal, 2007; Ferlay, 2007; Cheng, 2006; Noble, 2006), 31% of women are affected by cervical cancer (Suetens, 2009) and 70% of women are affected by ovarian cancer (Polascik, 2008). Since the causes of cancer still remain un-known, better treatment can be provided to detect from the early stage (Bangma, 2007; Schröder, 2009; Wink, 2007; Jesneck, 2007; Pelzer, 2005). The most modality for detecting the diagnosing is mammography (Bangma, 2007). To the low specificity mammography many biopsy operations are used (Bluth, 2007; Uof Pittsburgh Medical Centre, 2009; Yang, 2006). Currently one of the best alternative method is called ultrasound imaging technique. (Sahiner, 2007; Huang, 2005; Loch, 2007; Costantini, 2006). According to the survey showed that more than one out of every four researches using ultrasound images, which provides accurate results (Park, 2007). Ultrasound techniques are more convenient and safer than mammography (Salcudean, 2006). It is also cheaper than mammography. Different countries and continents use ultrasound technique (Cheng, 2010) which is more sensitive (Kalaivani Narayanan, 2009) and faster method. Hence it is valuable for people than 35 years of age ACS, 2011). Corresponding Author: S. Venkata Lakshmi, Research Scholar, CSE Manonmaniam Sundaranar University, Tirunelveli E-mail: [email protected] 93 S. Venkata Lakshmi and Dr. J. Janet, 2015 Advances in Natural and Applied Sciences, 9(7) June 2015, Pages: 92-99 Elastography is an automatic method for measuring the elasticity of tissue based on analysis of ultrasound tissue compression (Kerkar, 2006; Kanter, 2009; Krishna, 2006). This survey focuses different approaches for breast, prostate (Cohenford, 1997), cervix (Suetens, 2009) and ovarian (Polascik, 2008) cancer detection and classification method for Ultrasound images. Usually this involves four stages. Our work concentrates on the breast cancer. The basic steps in image processing steps are carried out in the processing of the cancer image. While preprocessing, the images can be an ultra sound image, HDR image or raw image and dicom images and they need to be pre-processed. Ultrasound images are affected by noise such as speckle noise (Fung, 1997; Muhammad, 2009), impulse noise (Eltonsy, 2007), multiplicative noise (Eltonsy, 2007). To suppress the noise some filtering techniques like (Eltonsy, 2007; Eltonsy,2006; Guo, 2005) wavelet domain techniques and de-speckling methods are used. Image Segmentation: This method sub categories the image into number of small portions and differentiate the object from the background. In Feature extraction and selection, we extract some features both from normal tissue and abnormal cancer tissue. So extracting and selecting some essential features is important for classification. After the feature extraction we classify the tissue and identify the normal and abnormal tissue. Related Work: A number of methods have been used to classify and/or detect abnormalities in medical images, such as wavelets, fractal theory and statistical methods. Generally, in these methods use features are extracted using image-processing techniques. A CAD system in which features are extracted using image processing techniques is developed in for detecting abnormalities. A large variety of techniques have been applied to the problem of mass detection, but most follow a two-step scheme. First, one or more features are computed for each pixel, after which each pixel is classified and the suspicious pixels are grouped into a number of suspicious regions. In the second step, these regions are classified as normal or abnormal regions, based on regional features like size, shape or contrast. The signs can indicate the presence of a lesion: a radiating pattern of spicules or a central mass. To detect the whole range from architectural distortions to circumscribed masses, both signs must be detected. The central mass is a more or less circular bright region with a diameter between 5mm and 5 cm. Convolution of the image with a zero mean filter with a positive centre and a negative surrounding area was used by a number of research groups to detect the mass, for example with the Laplacian of the Gaussian (LoG) or a Difference of Gaussians filter (DoG). Several works have been done to develop computer aided breast cancer detection and diagnosis tools et al. Proposed a technique in which presence of concentric layers surrounding a focal area with suspicious morphological characteristics and low relative incidence in the breast region is used for malignancy detection. Results were reported with 92, 88 and 81% sensitivity and developed a similar procedure to detect both masses and architectural distortion by finding those points which are covered by concentric layers of image activity. Also used Hausdorff fractal dimension and an SVM classifier to differentiate ROIs having architectural distortion. 72.5% accuracy was obtained with a set of 40 ROIs, of which 21 had normal tissue patterns and 19 had architectural distortion. Proposed work: Thresholding method is one of the most common methods for the segmentation of images into two or more clusters It is a simple and popular method for digital image processing that can be divided into three different types: global thresholding method, local thresholding method and optimal thresholding method. In the former, global thresholding methods are used to determinate a threshold for the entire image. An approach for breast cancer diagnosis in digital mammogram using wavelet transform is proposed in .Though there are different methods with rig let and curvelet our proposed method gives a better results compared with other methods. As the pre-processing of the input images the fuzzy enhancement is carried out. After the pre processing procedure with the mammogram image, the clustering process is carried out to perform the segmentation .After segmentation the classification is carried out with the feature extracted based on the energy with wavelet. The methodologies are explained in the below sections .The experimental results are given in section 4. . Fig. 1: Image Decomposition with Wavelet Transformation. A. Preprocessing: primary step is preprocessing .There are different pre In Every image processing technique the processing steps with different methods but we use 94 S. Venkata Lakshmi and Dr. J. Janet, 2015 Advances in Natural and Applied Sciences, 9(7) June 2015, Pages: 92-99 the fuzzy method to give novelty to the proposed work. Fuzzy enhancement methods can be used to enhance masses and micro-calcifications, upon enhancing mammograms containing masses and micro calcification and compared between fuzzy enhancement techniques and histogram equalization the fig 2 gives the steps involved in preprocessing. The Fig (4) gives the result of enhancement of the input image is comparatively good on comparing with the other preprocessing methods. Gray scale conversion preprocessing Input Image Histogram Equalization Fuzzy contrast Enhancement Fig. 2: Steps involved in Pre processing. B. Segmentation: Segmentation is to divide an image into region corresponding to objects. The fig 3 represents the various segmentation methods available for the classification of breast cancer. These objects include more information than pixels. Indeed, interpretation of images based on objects gives more illustrative and meaningful information’s than the information based on individual pixel interpretation. The principle aim of image segmentation is to apply a specific treatment or to interpret the image content. In this paper, a proposed algorithm for image segmentation based on PSO is used to automatically determine the threshold values in multilevel thresholding problem. The PSO algorithm is based on swarm behavior of birds where particles (in our case: pixels), fly through the search space using two simples equations for velocity and position. This algorithm has been widely used to solve global and local optimization problems. This algorithm has undergone several evolutions, we cite the Darwinian Particle Swarm Optimization (DPSO) and the fractional calculus based PSO called FODPSO (Cohenford, 1997). This work mainly focuses on using a new variant of PSO. PSO Algorithm: Initialization: 1. Initialize the position Xi and the velocity of each 2. 3. 4. 5. For I from 1 to N 6. Update: 7. If fitness(xi)< fitness(xi) then Up to date of P best: Pi=Xi Up to date of g best 8. For I from 1 to M 9. Up to date of Vi and Xi 10. end 11. end 12. end end Region –Based Segmentation Breast – region Segmentatio n Contour –Based Techniques Un Supervised Segmentation Mammogram Segmentation Techniques Region of Interest ROI Segmentatio n Techniques Cluster Segmentation Supervised Segmentation Pseudo color Segmentation Graph Segmentation Fig. 3: Over view of Segmentation methods. Variant feature Transformation 95 S. Venkata Lakshmi and Dr. J. Janet, 2015 Advances in Natural and Applied Sciences, 9(7) June 2015, Pages: 92-99 C. Feature Extraction: Feature extraction is the key for the classification of benign and malignant patterns in digital mammograms. The next step after detection and segmentation of the lesion is the extraction of features that would depict the class to which it belongs. Feature extraction methods examine objects and images to extract the most important features that represent various classes of objects. Features are used as inputs to classifiers that assign them to the class they represent. The extracted features are then used by a classifier to extract the different regions. In the proposed system, the training mammogram image is decomposed by using 2-level DWT with various directions. The fig(1)represents the DWT decomposition of a single image to one level where the HH, HL, LH, LL. are obtained. Then the energy of each directional sub-band is used as feature for the corresponding training image. This feature extraction method is applied to all the training samples and the features are stored in the database called as Feature Database (FD), and this database is used as one of the input to the classification phase. The energy of each directional sub-band of the image I is calculated by using the equation (1) Energy ( (1) Where band and W, H is width and height of the sub-band respectively. D. Classification: In the classification phase, the Support Vector Machine (SVM) algorithm is used as a classifier. SVM is a method for classifying objects based on closest training examples in the feature space. The selected features are provided as inputs to the classifier, with the known values. SVM is used as a classifier. SVMs are a set of related supervised learning methods that analyze data and recognize patterns, used for classification and regression analysis. The standard SVM is a non probabilistic binary linear classifier which predicts, the given input, with the two possible classes the input is a member of. Classification phase executes two phases. One is to classify mammograms into normal and abnormal cases and in the abnormal case it will represent the tissue contains tumor (micro calcification). Finally, the abnormal mammogram is classified into malignant or benign in the second stage. In this classification stage, SVM classifier in every phase is trained at specific number of training set in each category. Receiver Operating Characteristics (ROC) analysis is presented to evaluate the classification performance of the textural features extracted by texture-analysis method. is the pixel value of the eth sub- Fig. 4: (a) Fuzzy Contrasted Image and Histogram Representation(b)Segmentation Algorithm using FODPSO(c) Wavelet Decomposition. Exprimental Results: The above figure shows the results of enhancement carried out using the proposed method. Though there are many methods present for enhancing the input, the fuzzy contrast enhancement algorithm helps to minimize the computational time. The first figure represents the fuzzy enhancement algorithm and the second image represents the wavelet decomposition of the input with feature extraction is as shown. The result in the figure5 shows the output with their histogram results. The extracted features for test data and the trained data are as shown in the table 1. 96 S. Venkata Lakshmi and Dr. J. Janet, 2015 Advances in Natural and Applied Sciences, 9(7) June 2015, Pages: 92-99 Fig. 5: Experimental results of segmented micro calcification. The various parameters which is used for the evaluation is tabulated as in the table 2. The techniques can be employed to evaluate the enhancement and segmentation algorithms such as, sensitivity and specificity, receiver operating characteristic (ROC) and free-ROC (FROC). The results of diagnosing a mammogram can be classified as follows with the example of diagonosation. The results of the extracted features are tabulated in table 1. Table I: Extracted Features of Test and Train Dataset Features C1 C2 C3 N1 N2 Mean 88.27 41.44 56.01 23.73 65.74 Medium 80 31 72 4 69 Maximum 242 139 132 120 136 Minimum 12 0 0 0 0 Range 230 139 132 120 136 S. D 75.26 31.59 33.85 30.81 29.11 M.A.S.D 68 12 19 4 9 Mn.A..S.D. 66.31 25.69 29.2 26.54 20.63 L1. N 4.384e+06 2.894e+06 3.65e+06 1.47e+06 5.164e+06 L2 .N 2.585e+04 1.377e+04 1.671e+04 9677 2.015e+04 Max norm 242 139 132 120 136 C1, C2,C3 the cancer images N1,N2 are the normal images taken for testing and training .Standard Deviation is abbreviated S.D, M.A.S.D. is Maximum absolute standard deviation ,Mn.A.S.D. is Minimum absolute standard diviation,L1.N, L2.N N is norm values. No vertical lines in table. Statements that serve as captions for the entire table do not need footnote letters. a Gaussian units are the same as cgs emu for magnetostatics; Mx = maxwell, G = gauss, Oe = oersted; Wb = weber, V = volt, s = second, T = tesla, m = meter, A = ampere, J = joule, kg = kilogram, H = henry. Table 2: Segmentation Evaluation Methods. Parameters spatial overlap jaccard coeff accuracy sensitivity specificity false positive false negative ground truth PSO 0.9649 0.9298 56.0310 93.2918 99.3140 123 2422 36105 The various parameters which is used for the evaluation is tabulated as in the table 2. The techniques can be employed to evaluate the enhancement and segmentation algorithms such as, sensitivity and specificity, receiver operating characteristic (ROC) and free-ROC (FROC). The results of diagnosing a mammogram can be classified as follows with the example of diagonosation. DPSO 0.9635 0.9280 56.4077 93.2558 99.0116 179 2435 36105 FODPSO 0.9649 0.9282 57.2386 93.2835 99.0229 180 2425 36105 True positive (TP): sick people correctly diagnosed sick. False positive (FP): healthy people incorrectly diagnosed sick. True negative (TN): healthy people correctly diagnosed healthy. False negative (FN): sick people incorrectly diagnosed healthy. 97 S. Venkata Lakshmi and Dr. J. Janet, 2015 Advances in Natural and Applied Sciences, 9(7) June 2015, Pages: 92-99 Where sensitivity (true positive fraction (TPF)) is the fraction of sick people who are correctly diagnosed as positive and specificity (true negative fraction (TNF)) is the fraction of healthy people who are correctly diagnosed as negative. These measures specify the accuracy of the system for identifying the actual positive and actual negative patients respectively. However, the false-positive-fraction (FPF) and the false-negative fraction represent the frequencies of incorrect diagnoses, therefore: Falsenegative-fraction = 1 - TPF, and False positive- 1 0.95 0.9 fraction = 1 - TNF. There is an interrelationship between these measures which makes it important and meaningful to specify a single pair, either sensitivity and specificity, or TPF and FPF, but it is inadequate to use only one measure alone. Equation 2 shows sensitivity measure, while equation 3shows specificity measure Sensitivity = number of TP / (number of TP + number of FN) (2) Specificity = number of TN / (number of TN + number of FN) (3) JACCARD … Fig. 6: The comparative results of various methods. Conclusion: This paper presented a comprehensive classification and evaluation of mammogram enhancement and segmentation algorithms. The enhancement techniques were categorized into four distinct techniques. From the review, it is obvious that the results produced from the fuzzy enhancement techniques are best suited for enhancing both masses and micro-calcifications. On the other hand, the mammogram segmentation techniques were categorized into two distinct categories, and the regions of interest segmentation techniques were further categorized into subcategories. under the unsupervised, single view segmentation techniques are better suited for the segmentation of masses and micro-calcifications. 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