Clustering is the unsupervised classification of patterns (observations, data items, or feature vectors) into groups (clusters). The clustering problem has been addressed in many contexts and by researchers in many disciplines; this reflects its broad appeal and usefulness as one of the steps in exploratory data analysis. However, clustering is a difficult problem combinatorially, and differences in assumptions and contexts in different communities has made the transfer of useful generic concepts and methodologies slow to occur. This paper presents an overview of pattern clustering methods from a statistical pattern recognition perspective, with a goal of providing useful advice and references to fundamental concepts accessible to the broad community of clustering practitioners. We present a taxonomy of clustering techniques, and identify cross-cutting themes and recent advances. We also describe some important applications of clustering algorithms such as image segmentation, object recognition, and information retrieval.

/pdf/data-clustering-a-review-4c452f5cab.pdf

Data clustering: a review

“Unpaired Image-to-Image Translation using Cycle-Consistent Adversarial Networks”の学習報告

From the Publisher: 
The accessible presentation of this book gives both a general view of the entire computer vision enterprise and also offers sufficient detail to be able to build useful applications. Users learn techniques that have proven to be useful by first-hand experience and a wide range of mathematical methods. A CD-ROM with every copy of the text contains source code for programming practice, color images, and illustrative movies. Comprehensive and up-to-date, this book includes essential topics that either reflect practical significance or are of theoretical importance. Topics are discussed in substantial and increasing depth. Application surveys describe numerous important application areas such as image based rendering and digital libraries. Many important algorithms broken down and illustrated in pseudo code. Appropriate for use by engineers as a comprehensive reference to the computer vision enterprise.

Computer vision : a modern approach = 计算机视觉 : 一种现代的方法

Handwriting has continued to persist as a means of communication and recording information in day-to-day life even with the introduction of new technologies. Given its ubiquity in human transactions, machine recognition of handwriting has practical significance, as in reading handwritten notes in a PDA, in postal addresses on envelopes, in amounts in bank checks, in handwritten fields in forms, etc. This overview describes the nature of handwritten language, how it is transduced into electronic data, and the basic concepts behind written language recognition algorithms. Both the online case (which pertains to the availability of trajectory data during writing) and the off-line case (which pertains to scanned images) are considered. Algorithms for preprocessing, character and word recognition, and performance with practical systems are indicated. Other fields of application, like signature verification, writer authentification, handwriting learning tools are also considered.

/pdf/online-and-off-line-handwriting-recognition-a-comprehensive-4qmt9ty596.pdf

Online and off-line handwriting recognition: a comprehensive survey

IEEE Transactions on Pattern Analysis and Machine Intelligence

This paper proposes an Autonomous Machine Vision system which grasps a textureless object from a clutter in a single plane, rearranges it for proper placement and then places it using vision. It contributes to a unique vision-based pose estimation algorithm, collision free path planning and dynamic Change-Over algorithm for final placement.

https://web.iitd.ac.in/~sumeet/AIR_2015.pdf

Automated monocular vision based system for picking textureless objects

This paper proposes a novel recommendation engine to suggest coordinated outfits to the users that complements each other. The proposed recommendation model encodes subjective knowledge of clothing experts in Multimedia Web Ontology Language (MOWL) and makes use of evidential and causal reasoning scheme to deal with the media properties of concepts. Our approach automatically identifies the user visual personality and interprets the contextual meaning of media features of the garments in the context of input query image. As a result, personalized complementary garments based on occasion of wear are recommended to the user. We have validated our approach with garment preferences of various models with a large collection of shirts and trousers, collected from various websites.

Recommendation of complementary garments using ontology

We describe a novel appearance based scheme for extraction and representation of video objects. The tracking algorithm used for video object extraction is based upon a new eigen-space update scheme. We propose a scheme for organisation of video objects in an appearance based hierarchy. The appearance based hierarchy is constructed using a new SVD based eigen-space merging algorithm. The hierarchy enables approximate query resolution. Experiments performed on a large number of video sequences have yielded promising results.

An appearance based approach for video object extraction and representation

In this paper we present an approach for correcting character recognition errors of an OCR which can recognise Indic Scripts. Suffix tree is used to index the lexicon in lexicographical order to facilitate the probabilistic search. To obtain the best probable match against the mis-recognised string, it is compared with the sub-strings (edges of suffix tree) using similarity measure as weighted Levenshtein distance, where Confusion probabilities of characters (Unicodes) are used as substitution cost, until it exceeds the specified cost k. Retrieved candidates are sorted and selected on the basis of their lowest edit cost. Exploiting this information, the system can correct non-word errors and achieves maximum error rate reduction of 33% over simple character recognition system.

Probabilistic Approach for Correction of Optically-Character-Recognized Strings Using Suffix Tree

With the availability of large collection of document images in Indian languages, image based retrieval has gained popularity. The performance of such systems is effected by the presence of degraded and noisy images. Moreover, Optical character recognition systems for Indian scripts are not yet robust, leading to noisy OCR'ed text. Information retrieval system designed using inputs from both modalities (image features and OCR based recognition data) will lead to better retrieval performance in contrast to usage of individual modality. In this paper we present a indexing methodology that uses multiple kernel learning to combine features from different modalities by joint optimization of search time and accuracy. The evaluation of the proposed methodology is demonstrated on document images of Bangla and Devanagari script.

Santanu Chaudhury

Papers

Automated monocular vision based system for picking textureless objects

Recommendation of complementary garments using ontology

An appearance based approach for video object extraction and representation

Probabilistic Approach for Correction of Optically-Character-Recognized Strings Using Suffix Tree

Document indexing framework for retrieval of degraded document images