International Journal of Engineering Trends and Technology (IJETT) – Volume 12 Number 9 – Jun 2014 A Novel Improved Technique of Image Indexing For Efficient Content Based Image Retrieval Using Local Patterns Srikant S K#1, Dr T C Manjunath*2 #1 PG student, Dept of ECE, HKBK college of Engineering, Bangalore, India #2 Principal, HKBK college of Engineering, Bangalore, India Abstract— with the rapid growth in the collection of digital libraries due to large availability of digital cameras, mobile phones and other multimedia, necessity for large image database has raised. Therefore efficient way of retrieving the images has become an important research area. Content based image retrieval is a method to retrieve the images from the large database based on the image content. Here in this work, we propose a novel image indexing algorithm for CBIR using local patterns. The main objective of the proposed method is to retrieve the best relevant images from the stored database that matches the query image. LTrP algorithm encodes the relationship between the referenced pixel and its neighboring pixel based on the directions which are calculated using the firstorder derivatives in horizontal and vertical direction. Further in order to improve the performance we are combining LDP and LTP with the LTrP and construct the feature vector. The patterns of the query image and images in database are compared to produce the retrieved relevant image. The performance resulting from the combination of LTrP, Ldp and Ltp has been analyzed. The analysis shows that the proposed method improves the retrieval result in terms of average retrieval rate, as compared with the existing methods. KEYWORDS: Content-Based Image Retrieval (CBIR), Local Tetra Patterns (LTrPs), Local Derivative Pattern (LDP), Local Ternary Pattern (LTP). I. INTRODUCTION In the recent years we are witnessing a rapid growth in the volume of image and video collections due to the large availability of digital cameras, web cameras and mobile phones inbuilt with such devices. The information is available in huge quantity and it has become a very difficult task to access and manage this huge database. So there should be some means that can help the user in accessing the database easily and in a more convenient way. Content-based image retrieval (CBIR) is one of the best technique for such applications. Today content based image retrieval has become an important research area in the field of digital image processing techniques. The research of cbir has been started in early 1990’s and is still a hot topic in this 21st century. Due to the growing demand of cbir in the field of multimedia such as crime prevention, biometric techniques of identification and many others make the application developers to build a technique for retrieving the images efficiently. The general ISSN: 2231-5381 method adopted for browsing the database to search for identical images involves text based keywords or by giving description of the image which would be impractical since it takes a lot of time and requires user intervention. A more practical way is to use Content based image retrieval (CBIR) technology. CBIR has provided an easy way to retrieve images based on the visual content or features of the images itself. The CBIR system simply extracts the content of the query image, matches them to contents of the search image. CBIR is defined as the process to find similar picture or pictures in the image database when an input query image is given. Suppose consider an image of a flower as the query image, then the system must be able to produce all similar images of a flower from the database to the users. This is done by picking up the features of the images such as color, texture and shape. These image features is used to comparability among the query image and images in the database. A comparison or similarity algorithm is used to calculate the degree of similarity between those two images. Images in the database which has similar images features to the query image (having minimum distance between them) is then retrieved and displayed to the user. Basically cbir is a two step process which is Feature Extraction and Image Matching (also known as feature matching). Feature Extraction is the process to extract image features to a distinguishable extent. Information extracted from images such as color, texture and shape are known as feature vectors. The feature extraction is done on both input query images and images stored in the database. Image matching involves using the features of both images and comparing them to search for similar features of the images in the database. Using multiple feature vectors to describe an image during retrieval process increases the accuracy when compared to the retrieval using single feature vector. For example, searching of image based on its color and texture provides a better result than using a single color feature since two features are now used as indicator during matching process. Texture analysis of an image has been extensively used in computer vision and pattern recognition applications because of its potentiality in extracting the prominent features. http://www.ijettjournal.org Page 432 International Journal of Engineering Trends and Technology (IJETT) – Volume 12 Number 9 – Jun 2014 Texture retrieval is a branch of texture analysis that has attracted wide attention from industries since this is well suitable for the identification of products such as ceramic tiles, marble, slabs, etc. II. RELATED WORK In this paper the analysis of image indexing and retrieval algorithm using combination of local patterns for content-based image retrieval (CBIR) has been proposed. The standard local derivative pattern (Ldp) and local ternary pattern encodes the relationship between the referenced pixel and its surrounding neighbors by computing gray-level difference. The ltrp method encodes the relationship between the referenced pixel and its neighbors based on the directions that are calculated using the first-order derivatives in vertical and horizontal directions [1]. Muller et al. [6] provides a comprehensive and broad review of CBIR systems for medical applications. The Image Retrieval for Medical applications (IRMA) project [7] [8] describes CBIR methods for medical images using intensity distribution and texture measure. The main characteristics of this project are its support to allow the retrieval of similar images from heterogeneous databases. Ojala et al. [10] presents a simple and efficient multiresolution method to gray-scale and rotation invariant texture classification based on local binary patterns and nonparametric discrimination of sample and prototype distributions. Laio et al [11] proposed an approach, in which features are robust to image rotation, less sensitive to histogram equalization and noise. It comprises of two sets of features: dominant local binary patterns (DLBP) in a texture image and the supplementary features extracted by using the circularly symmetric Gabor filter responses. A combined completed LBP (CLBP) scheme [12] is developed for texture classification in which a local region is represented by its centre pixel and a local difference sign-magnitude transform (LDSMT). Ahonen et al. [13] reported a novel and efficient facial image representation based on local binary pattern (LBP) texture features. The LBP technique [5] has been widely used in numerous applications due to its finest texture descriptor performance. It has proven to be highly discriminative and its key advantages, mainly, its invariance to monotonic gray-level changes and computational efficiency, make it suitable for demanding image analysis task. Zhang et al. proposed local derivative patterns (LDPs) for face recognition, in which LDP templates extract high-order local information by encoding various distinctive spatial relationships contained in a given local region[14]. Author et al. proposed a novel approach for face representation and recognition by examining the information jointly in image space, scale and orientation domains. Information collected from different domains is explored and examined to give an efficient face representation for recognition. The main challenge is that the use of LBP, LDP ISSN: 2231-5381 and their extended techniques are not so much reliable under the unconstrained lighting conditions. To accomplish this challenge the local ternary pattern (LTP) [16] has been introduced for image recognition under different lighting conditions. LTP eliminates most of the effects of changing illumination and presents a local texture descriptor which is unique and less sensitive to noise in uniform region. III. PROPOSED WORK In the proposed system the content based image retrieval algorithm is implemented using the combination of local patterns (LTrp, Ltp and Ldp). More detailed information can be collected from an image using these local patterns. The ltrp encodes the relationship between referenced pixel and its neighboring pixel based on the directions. The directions are calculated using first order derivatives in horizontal and vertical directions. The Ldp and Ltp encodes the relationship between center pixel and neighboring pixels by computing gray level difference. These methods extract the information from an image based on the distribution of edges in more than two directions. The combination of these different patterns will help in collecting more detailed information from an image. The complete architecture of the proposed system is shown below in the figure 1 Fig 1 Block diagram of the proposed framework Initially, the query image is loaded and converted into grayscale image. As the dataset may be of different size, the image is resized. After resizing, the first-order derivative in both horizontal and vertical axis is applied and direction of every pixel is calculated. Based on the direction of the centre pixel the patterns are divided into four parts. The tetra patterns are calculated and separated into three binary patterns. Also http://www.ijettjournal.org Page 433 International Journal of Engineering Trends and Technology (IJETT) – Volume 12 Number 9 – Jun 2014 the features are extracted from ternary and derivative patterns (ltp & ldp) and then all patterns are combined to form the feature vector. The query and database image then is compared using Euclidean distance technique for similarity measurement. Finally, the best matched images are retrieved from the image database in response to the query image. The proposed system has the following structure. 1) Image Database: A database which contains number of mages with any one of the formats .bmp, .jpg, .tiff. is required. 2) Query: The user provides a sample image or sketched figure as the query for the system. 3) Preprocessing: this involves resizing and rgb to gray scale conversion of the input image for easy computations 4) Feature Extraction: The different features like local derivative pattern, local ternary pattern and local tetra patterns are to be collected from the database images and input query image based on the relationship between pixels value. There are various kinds of low-level visual features to represent an image, such as color, texture, shape, and spatial relationship. Since one type of features can only represent part the image properties, a lot of work done on the combination of these features. 5) Histogram Representation: The features extracted from different patterns are concatenated and represented through histogram to arrive at the feature vector for matching. 6) Similarity Matching: This involves matching these features to yield a result that is visually similar. The commonly used similarity measure method is the Distance method. There are different distances available such as Euclidean distance, City Block Distance, Canberra Distance. ………………………..eqn (1) B. Local Derivative Pattern (Ldp) LBP actually encodes the binary result of the first-order derivative among local neighbors by using a simple threshold function, which is incapable of describing more detailed information. They considered the LBP as the no directional first-order local pattern operator and expanded it to higher order (nth-order) called the LDP. The LDP contains more detailed discriminative features as compared with the LBP. LDP encodes the higher-order derivative information which contains more detailed discriminative features that the firstorder local pattern (LBP) cannot obtain from an image. Given an image I (Z), the first-order derivative along 0 0 ,450 ,900 ,135 directions are denoted as where α= along 00,450 ,900 ,1350 .Let gc be a point in I(Z), and Zi , i = 1,……,8 be the neighboring point around gc. The four firstorder derivatives at Z = gc can be written as c) eqn(2) c) c) The second –order directional LDP, in α direction at Z = gc is defined as IV. IMPLEMENTATION DETAILS 1. LOCAL FEATURE EXTRACTION A. Local Ternary Pattern (LTP) LBPs have proven to be highly discriminative features for texture classification and are resistant to lighting effects in the sense that they are invariant to monotonic gray-level transformations. However because they threshold at exactly the value of the central pixel they tend to be sensitive to noise, particularly in near-uniform image regions, and to smooth weak illumination gradients. Many facial regions are relatively uniform and it is legitimate to investigate whether the robustness of the features can be improved in these regions. LTP is a three-valued code, in which gray values in the zone of width ± T around gc are quantized to zero, those above (Gc+T) are quantized to +1, and those below (Gc-T) are quantized to-1.Local Ternary Patterns are an extension of Local Binary Pattern. Unlike LBP, it does not threshold the pixels into 0 and 1 rather it uses a threshold constant T to threshold pixels into three values. Here T is a user specified threshold, So LTP code more resistant to noise. LTP can be determined by equation (1). ISSN: 2231-5381 …………………....eqn(3) Where Where f2(x,y) is a binary coding function determining the types of local pattern transitions. It encodes the co-occurrence of two derivative directions at different neighboring pixel. Finally, the second-order Local Derivative Pattern is defined as the concatenation of four 8-bit directional LDP’S http://www.ijettjournal.org .. …………………..eq(4) Page 434 International Journal of Engineering Trends and Technology (IJETT) – Volume 12 Number 9 – Jun 2014 C. Local tetra pattern (LTrp) Local tetra pattern technique encodes the relationship between the centre pixel and its neighbors, based on the directions that are calculated using the first order derivatives in vertical and horizontal directions. The first-order derivatives at the centre pixel gc can be written as From above equation (7), we get 8-bit tetra pattern for each centre pixel. Then, we separate all patterns into four parts based on the direction of centre pixel. Finally, the tetra patterns for each part (direction) are converted to three binary patterns. Let the direction of centre pixel obtained using (2) be “1”; then, can be defined by segregating it into three binary patterns as follows |direction ……………………………eq(5) and the direction of the centre pixel can be calculated as = 2. …………………………eq(6) From (6), it is evident that the possible direction for each centre pixel can be 1, 2, 3, or 4, and eventually, the image is converted into four values, i.e., directions. The second-order tetra pattern is defined as ( ) |direction SIMILARITY MEASUREMENT To retrieve the similarity images from the large image dataset, three types of Distance Metric Measures like Euclidean Distance, Chi- Square Distance and Weighted Euclidean but in the proposed method Euclidean distance is used. Euclidean Distance: The formula of Euclidean distance is = Where ……………………………….eq(7) The Euclidean distance is calculated between the query image and every image in the database. This process is repeated until all the images in the database have been compared with the query image. Upon completion of the Euclidean distance algorithm, we have an array of Euclidean distances, which is then sorted. The five topmost images are then displayed as a result of the texture search. The algorithm flow for the proposed work is given below Input: Query image; Output: Retrieval result Fig 2 Calculation Of Tetra Pattern ISSN: 2231-5381 Load the query image Convert the image into grayscale Resize the image. Segmenting the image Apply the first-order derivatives in horizontal and vertical axis. Calculate the direction for every pixel. Calculate the tetra patterns, derivative patterns and ternary patterns. Combine all the patterns from all regions. Construct the feature vector. Compare the query image with the images in the database using Euclidian distance method. Retrieve the images based on the best matches and display the result on GUI. http://www.ijettjournal.org Page 435 International Journal of Engineering Trends and Technology (IJETT) – Volume 12 Number 9 – Jun 2014 Performance Parameters Precision and Recall (P-R): The images are retrieved and measured against P-R as Number of relevant images retrieved P= Total Number of images retrieved Total number of relevant images in the database R= Number of relevant images retrieved. Now in the example given below we have applied the query image of skull and have retrieved 7 Similar images from the the database Fig 3 Proposed work Flow diagram V. EXPERIMENTAL RESULTS The database consists of a large number of images of various contents ranging from animals to outdoor sports to natural images. These images have been pre-characterized into different categories each of size 100 by domain experts. The images in the database contain the different dimensions and it’s collected into single database images. The performance of the proposed method is measured in terms of average precision and average recall. Performance analysis shows that the proposed method improves the retrieval result from in terms of average precision/average recall rate. Fig 5 Retrieved images for a given query image as human skull. Fig 4 Sample Database Images ISSN: 2231-5381 Fig 6 Bar-chart Representation showing performance for different classes http://www.ijettjournal.org Page 436 International Journal of Engineering Trends and Technology (IJETT) – Volume 12 Number 9 – Jun 2014 REFERENCES Fig 7 Showing the comparison of accuracy rate between local pattern method and shape based method. VI. CONCLUSION AND FUTURE ENHANCEMENT Conclusion It is clear that the rate at which the number of images available to the public in digital form grows will increase in the coming years, because of new image compression techniques, cheaper storage, and faster Internet connections. Hence, the role of CBIR (certainly within the framework of content-based multimedia retrieval) in the future will become even more important. In this paper we proposed novel approach referred as LTrPs for CBIR was presented. The LTrP encodes the images based on the direction of pixels that are calculated by horizontal and vertical derivatives. In addition to this we combined ldp and ltp with ltrp and the performance was analyzed. This Retrieval algorithm mainly reduces the computational time and at the same time increases the user interaction. The retrieval accuracy is also increased to greater extent as the images are retrieved on the basis of both pixel information and colour feature. 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Image Process., Vol. 19, No. 2, pp. 533–544, Feb. 2010. Future Enhancement In this proposed system, only horizontal and vertical pixels have been used for 1st order derivative calculation in calculating direction pixels. Results can be further improved by considering the diagonal of pixels for derivative calculations in addition to horizontal and vertical directions. Due to the effectiveness of the proposed method, it can be also suitable for other pattern recognition applications such as face recognition, fingerprint recognition, etc. ISSN: 2231-5381 http://www.ijettjournal.org Page 437