ENHANCED CBIR MECHANISM USING STEERABLE PYRAMID AND MEDIAN VECTOR ALGORITHM

In the field of computer vision and image processing CBIR (Content based image retrieval) system become an active research area. The CBIR technique involves feature extraction based on image features (like color, shape and texture) and defining rules for comparing image. A classifier is also used by authors for image classification. For this purpose an image database taken from James Z. Wang research group website is used by many authors. Due to enormous increase in the size of database traditional methods of image retrieval by using keywords does not provide accurate result. Thus the concept of CBIR system is emerged. In last couple of years many method of feature extraction is developed but since now researcher are not able to develop a system which has gained high accuracy of human visual perception in distinguishing pictures. Therefore earlier researchers have concentrated to increase the retrieval accuracy of CBIR system by using different combination of features. The objective of this paper is to present review on a CBIR technique which combined four kinds of features set including every kind of feature for developing feature vector. Color based features (histogram), statistical features (mean, median and standard deviation), spatial features (Gabor feature and wavelet features) and texture features (GLCM) is used for forming feature vector. A SVM classifier is used with CBIR system to increase retrieval accuracy. SVM (support vector machine) is a machine learning classifier which provides good classification accuracy. Keywords: CBIR, SVM, NN, GLCM, HSV Color space, Euclidean distance matrix.

Content Based Image Retrieval (CBIR) depends on the visual content of an image for obtaining similar images. Research on CBIR faces a challenge of semantic gap between low level features and high level visual content. The optimal solution must reduce the computational complexity and computational time in retrieval process. Relevance Feedback is a solution to reduce the semantic gap. A new framework for content based image retrieval is proposed which is Bipartite Reiterative algorithm. This gives an approach of iteration to relevance feedback mechanism. It consists of two levels which are basic retrieval scheme and reiterative feedback scheme. Positive images are obtained from the user as part of the basic retrieval scheme. New feedback algorithm is developed based on weights assigned to visual attributes. The weights are inversely proportional to the visual attribute distance between query image and the positive images given by the user. Iterative feedback query can be performed after the user feedback. The query will be progressed according to the user feedback. The algorithm reduces the computational complexity and computational time in image retrieval.

This paper introduces a new CBIR system based on two different approaches in order to achieve the retrieval efficiency and accuracy. Color and texture information is extracted and used in this work to form the feature vector. To do the texture feature extraction this system uses DCT and DCT Wavelet transform to generate the feature vectors of the query and database images. Color information extraction process includes separation of image into R, G and B planes. Further each plane is divided into 4 blocks and for each block row mean vectors are calculated. DCT and DCT wavelet is applied over row mean vector of each block separately and 4 sets of DCT and DCT wavelet coefficients are obtained respectively. Out of these few coefficients are selected from each block and arranged in consecutive order to form the feature vector of the image. Variable size feature vectors are formed by changing the no of coefficients selected from each row vector. Total 18 different sets are obtained by changing the no of coefficients selected from each block. These two different feature databases obtained using DCT and DCT wavelet are then tested using 100 query images from 10 different categories. Euclidean distance is used as similarity measure to compare the image features. Euclidean distance calculated is sorted into ascending order and cluster of first 100 images is selected to count the images which are relevant to the query image. Results are further refined using second level thresholding which uses three criteria which can be applied to first level results. Results obtained are showing the better performance by DCT wavelet as compare to DCT transform. Keywords-component; DCT; DCT wavelet; Eucidean distance. I. INTRODUCTION Large amount of images are being generated, stored and used daily in various real life applications through various fields like engineering, medical sciences, biometrics, architectural designs and drawings and many other areas. Although various techniques are being designed and used to store the images efficiently, still it demands to search new effective and accurate techniques to retrieve these images easily from large volume of databases. Text based image retrieval techniques have tried in this direction which has got many constraints and drawbacks associated with it which is continuously encouraging the researchers to come up with the new techniques to retrieve the images based on contents instead of text annotations. Image contents are broadly classified into global and local contents. Local contents define the local attributes of the image like color, shape and texture

Technological advances in digital imaging, broadband networking, and data storage have motivated people to communicate and express by sharing images, video, and other forms of media online [1]. Although the problems of acquiring, storing and transmitting the images are well addressed, capabilities to manipulate, index, sort, filter, summarize, or search through image database lack maturity. Modern image search engines [1–3, 30] retrieve the images based on their visual contents, commonly referred to as Content Based Image Retrieval (CBIR) systems. CBIR systems have found applications in various fields like fabric and fashion design, interior design as panoramic views [5, 20, 38–41], art galleries [22], museums, architecture/ engineering design [22], weather forecast, geographical information systems, remote sensing and management of earth resources [40, 41], scientific database management, medical imaging, trademark and copyright database management, the military, law enforcement and criminal investigations [41], intellectual property, picture archiving and communication systems, retailing and image search on the Internet (very general image content).

Histogram refinement for texture descriptor based image retrieval

Content-based image retrieval (CBIR) has been widely researched for medical images. In application of histo- pathological images, there are two issues that need to be carefully considered. The one is that the digital slide is stored in a spatially continuous image with a size of more than 10K x 10K pixels. The other is that the size of query image varies in a large range according to different diagnostic conditions. It is a challenging work to retrieve the eligible regions for the query image from the database that consists of whole slide images (WSIs). In this paper, we proposed a CBIR framework for the WSI database and size-scalable query images. Each WSI in the database is encoded and stored in a matrix of binary codes. When retrieving, the query image is first encoded into a set of binary codes and analyzed to pre-choose a set of regions from database using hashing method. Then a multi-binary-code-based similarity measurement based on hamming distance is designed to rank proposal regions. Finally, the top relevant regions and their locations in the WSIs along with the diagnostic information are returned to assist pathologists in diagnoses. The effectiveness of the proposed framework is evaluated in a fine-annotated WSIs database of epithelial breast tumors. The experimental results show that proposed framework is both effective and efficiency for content-based whole slide image retrieval.

Illumination distortion due to uncontrolled lighting can severely degrade the color appearance of a photo. Frequently, the desired colors for objects in a newly taken query image are found in a previously stored database image. Then, the goal is to change the colors in the query image to match the colors in the database image. This paper presents a color restoration system that automatically retrieves a database image which matches the query image, even if the two images are taken from different viewpoints and under different illuminations. Robust features enable both accurate retrieval from the database and efficient sampling of the color differences between the query and database images. A spatially varying color mismatch model is generated, and the colors of the query image are effectively restored.

‘A visual idea is more powerful than verbal idea’, ‘A picture is worth more than ten thousand words’, ‘No words can convey what a picture speaks’, ‘A picture has to be seen and searched as a picture only’ are few of the well-known sayings that imply the certainty for the widespread availability of images. Common sense evidence suggests that images are required for a variety of reasons, like, illustration of text articles, conveying information or emotions that are difficult to describe in words, display of detailed data for analysis (medical images), formal recording of design data for later use (architectural plans) etc. The advent of digital photography combined with decreasing storage and processing cost, allows more and more people to have their personal collection of photographs and other visual content available on the internet. Organising these digital images into a small number of categories and providing effective indexing is imperative for accessing, browsing and retrieving useful data in “real time”. The process of digitization does not in itself make image collections easier to manage. Some form of indexing (cataloguing) is still necessary. People’s interest to have their own digital libraries has burgeoned and hence requires a data structure to preserve the images for a long time and also provide easy access to the desired images. These requirements have indeed forced the design of specialized imaging systems/ image databases, such that an access to any image is effective and efficient. An efficient image archival and retrieval system is characterized by its ability to retrieve relevant images based on their visual and semantic contents rather than using simple attributes or keywords assigned to them. Thus, it is necessary to support queries based on image semantics rather than mere-pixel-to-pixel matching. An image archival and retrieval system should therefore allow adequate abstraction mechanisms for capturing higher level semantics of images in order to support content addressability as far as possible. That is, for two images to be similar, not only the shape, color and texture properties of individual image regions must be similar, but also they must have the same arrangement (i.e., spatial relationships) in both the images. In fact, this is the strategy, which is generally being employed by our vision system most of the times. An effective method of representing images depends on the perception of knowledge embedded in images in terms of objects/components (generally known as elements) present in them along with their topological relationships. The perception of topological relationships, especially spatial relationships existing among the significant elements of an image, helps in making the image database system more intelligent, fast and flexible. An obvious method to search an image database is sequential scanning. The query is matched with all stored images (i.e., the representation of the query is matched with all representations stored in the image database) one by one. Retrievals may become extremely slow, especially when database search involves time consuming image matching operations. To deal with slow retrieval response times, and high complexity matching, an image database must utilize indexing methods that are faster than sequential scanning methods. In traditional image database systems, the use of indexing to allow database accessing has been well established. Analogously, image indexing techniques have been studied during the last decade to support representation of pictorial information in an image database and also to retrieve information from an image database. The use of significant elements present in images along with their topological relationships as indexes is the basic issue of the indexing methodologies developed to this aim.

As the use of digital media increases, effective retrieval and management techniques become more important. In order to extract useful information from this huge amount of data, many content based image retrieval (CBIR) systems have been developed. A typical CBIR system captures image features such as color, texture, or shape of objects in the query image and tries to retrieve images from the database with similar features. The main advantage of CBIR systems with relevance feedback is that these systems take into account the gap between the high-level concepts and low-level features and subjectivity of human perception of visual content. In this paper, a CBIR system based on color histogram has been presented and a new approach for image storage and retrieval called association-based image retrieval (ABIR) has been studied. The results of both systems have been shown.

Basic group of visual techniques such as color, shape, texture are used in Content Based Image Retrievals (CBIR) to retrieve query image or sub region of image to find similar images in image database.To improve query result, relevance feedback is used many times in CBIR to help user to express their preference and improve query results.In this paper, a new approach for image retrieval is proposed which is based on the features such as Color Histogram, Eigen Values and Match Point.Images from various types of database are first identified by using edge detection techniques .Once the image is identified, then the image is searched in the particular database, then all related images are displayed.This will save the retrieval time.Further to retrieve the precise query image, any of the three techniques are used and comparison is done w.r.t.average retrieval time.Eigen value technique found to be the best as compared with other two techniques.

With the rapid advancement of digital imaging technologies, and the use of large volume image databases in various applications, it becomes imperative to build an automatic and an efficient image retrieval system. Content Based Image Retrieval (CBIR) is most emerging and vivid research area in computer vision, in which unknown query image assigns to the closest possible similar images available in the database. Current systems mainly use colour, texture, and shape information for image retrieval using similarity measures between query and database images features. Here this work, proposed a classification system that allows recognizing and recovering the class of a query image based on its visual content. This successful categorization of images greatly enhances the performance of retrieval by filtering out irrelevant classes. In this way we have done the comparative analysis of various features as an individual or in combinations, with direct similarity measure and proposed framework. Experimentson benchmark Wang database show that the proposed classification & retrieval framework performs significantly better than the common framework of distances.

In this paper, we propose a new visual feature extraction method for content-based image retrieval (CBIR) based on wavelet transform which has both spatial-frequency and multi-resolution characteristics. We extract visual features for each frequency band in wavelet transformation and use them for CBIR. The lowest frequency band involves utilizing the spatial information of an original image. We extract 64 feature vectors using fuzzy homogeneity in the wavelet domain, which considers both the wavelet coefficients and the spatial information of each coefficient. In addition, we extract 3 feature vectors using the energy values of high frequency bands, and store those to the image database. As a query, we retrieve the most similar image from the image database according to the 10 largest homograms (normalized fuzzy homogeneity vectors) and 3 energy values. Simulation results show that the proposed method has good accuracy in image retrieval using 90 texture images.

Objectives: Nowadays, the capacity of digital image information is rapidly surging. The computational complexity of retrieving images from database also increases. Methods/Statistical Analysis: Texture and colour are the most important components of visual information which can be used effectively to reduce the complexity. This paper presents Content- Based Image Retrieval System (CBIR) based on texture and colour similarity. The RGB colour space and the colour histogram are used as the colour feature of each image. The texture of each image is obtained by applying gray level co-occurrence matrix. Findings: Based on the similarity between image features CBIR methods retrieve images accurately from the image database. But the traditional system will work well only for the data set which has more dissimilarity. In this study, based on combining the Gaussian Mixture Model (GMM) with k-means clustering algorithm, a new hybrid algorithm for clustering is proposed. A one to one matching scheme is used to compare the query and target image on the basis of all the features extracted. This hybrid Gaussian mixture model will provide more accurate retrieval in the case of the dissimilarity between the image data set is very low. The proposed system is capable of working fewer dissimilarity data set as well more dissimilarity data. Applications/Improvements: The proposed hybrid retrieval method provide more accurate retrieval with the precision measures of 98% and also more robustness with retrieval of 95%.

Image retrieval is an important problem in multimedia systems. It is determined as the process of searching and fetching images from a dataset. Content-based Image Retrieval (CBIR) is a significant and challenging field of research in digital image processing. The CBIR system's essential requirement is to retrieve the relevant information following a query image with higher system output from a large image database. Unfortunately, not all the methods are suitable to be used to get high accuracy of retrieval. Therefore, this research aims to classify the data of query image with the data of image database to get a similar image retrieval using Support Vector Machine (SVM) and validate its accuracy based on the classification for the performance evaluation using the precision-recall measure. The critical point of SVM is to get an optimal hyperplane that separates the data points into two classes. This method was applied to different image databases because the classified-based proposed scheme proved better performance than various existing methods. This project assessed experimental results toward 500 images of the Caltech-256 image dataset to demonstrate the proposed method. For retrieving a similar image following the query image, 20 images from five classes were successfully retrieved by using this method. It will show that the SVM method's average accuracy from all image classes is 94.79%.

Any city-scale visual localization system has to overcome long-term appearance changes, such as varying illumination conditions or seasonal changes between query and database images. Since semantic content is more robust to such changes, we exploit semantic information to improve visual localization. In our scenario, the database consists of gnomonic views generated from panoramic images (e.g. Google Street View) and query images are collected with a standard field-of-view camera at a different time. To improve localization, we check the semantic similarity between query and database images, which is not trivial since the position and viewpoint of the cameras do not exactly match. To learn similarity, we propose training a CNN in a self-supervised fashion with contrastive learning on a dataset of semantically segmented images. With experiments we showed that this semantic similarity estimation approach works better than measuring the similarity at pixel-level. Finally, we used the semantic similarity scores to verify the retrievals obtained by a state-of-the-art visual localization method and observed that contrastive learning-based pose verification increases top-1 recall value to 0.90 which corresponds to a 2% improvement.