Scene categorization with multi-scale category-specific visual words

IS&T/SPIE Conference on Intelligent Robots and Computer Vision XXVI: Algorithms and TechniquesIn this paper, we propose a scene categorization method based on multi-scale category-specific visual words. The proposed method quantizes visual words in a multi-scale manner which combines the global-feature-based and local-feature-based scene categorization approaches into a uniform framework. Unlike traditional visual word creation methods which quantize visual words from the whole training images without considering their categories, we form visual words from the training images grouped in different categories then collate the visual words from different categories to form the final codebook. This category-specific strategy provides us with more discriminative visual words for scene categorization. Based on the codebook, we compile a feature vector that encodes the presence of different visual words to represent a given image. A SVM classifier with linear kernel is then employed to select the features and classify the images. The proposed method is evaluated over two scene classification datasets of 6,447 images altogether using 10-fold cross-validation. The results show that the classification accuracy has been improved significantly comparing with the methods using the traditional visual words. And the proposed method is comparable to the best results published in the previous literatures in terms of classification accuracy rate and has the advantage in terms of simplicity. © 2009 SPIE-IS&T.published_or_final_versio

Scene categorization with multiscale category-specific visual words

We propose a novel scene categorization method based on multiscale category-specific visual words. The novelty of the proposed method lies In two aspects: (1) visual words are quantized In a multiscale manner that combines the global-feature-based and local-feature-based scene categorization approaches into a uniform framework; (2) unlike traditional visual word creation methods, which quantize visual words from the entire set of training, we form visual words from the training images grouped in different categories and then collate visual words from different categories to form the final codebook. This generation strategy Is capable of enhancing the discriminative ability of the visual words, which is useful for achieving better classification performance. The proposed method is evaluated over two scene classification data sets with 8 and 13 scene categories, respectively. The experimental results show that the classification performance is significantly improved by using the multiscale category-specific visual words over that achieved by using the traditional visual words. Moreover, the proposed method Is comparable with the best methods reported in previous literature in terms of classification accuracy rate (88.81% and 85.05% accuracy rates for data sets 1 and 2, respectively) and has the advantage in simplicity. © 2009 Society of Photo Optical Instrumentation Engineers.published_or_final_versio

Blending Learning and Inference in Structured Prediction

In this paper we derive an efficient algorithm to learn the parameters of structured predictors in general graphical models. This algorithm blends the learning and inference tasks, which results in a significant speedup over traditional approaches, such as conditional random fields and structured support vector machines. For this purpose we utilize the structures of the predictors to describe a low dimensional structured prediction task which encourages local consistencies within the different structures while learning the parameters of the model. Convexity of the learning task provides the means to enforce the consistencies between the different parts. The inference-learning blending algorithm that we propose is guaranteed to converge to the optimum of the low dimensional primal and dual programs. Unlike many of the existing approaches, the inference-learning blending allows us to learn efficiently high-order graphical models, over regions of any size, and very large number of parameters. We demonstrate the effectiveness of our approach, while presenting state-of-the-art results in stereo estimation, semantic segmentation, shape reconstruction, and indoor scene understanding

Automatic Video Classification

Within the past few years video usage has grown in a multi-fold fashion. One of the major reasons for this explosive video growth is the rising Internet bandwidth speeds. As of today, a significant human effort is needed to categorize these video data files. A successful automatic video classification method can substantially help to reduce the growing amount of cluttered video data on the Internet. This research project is based on finding a successful model for video classification. We have utilized various schemes of visual and audio data analysis methods to build a successful classification model. As far as the classification classes are concerned, we have handpicked News, Animation and Music video classes to carry out the experiments. A total number of 445 video files from all three classes were analyzed to build classification models based on Naïve Bayes and Support Vector Machine classifiers. In order to gather the final results we developed a “weighted voting - meta classifier” model. Our approach attained an average of 90% success rate among all three classification classes

A Survey On Medical Digital Imaging Of Endoscopic Gastritis.

This paper focuses on researches related to medical digital imaging of endoscopic gastritis

Image classification by visual bag-of-words refinement and reduction

This paper presents a new framework for visual bag-of-words (BOW) refinement and reduction to overcome the drawbacks associated with the visual BOW model which has been widely used for image classification. Although very influential in the literature, the traditional visual BOW model has two distinct drawbacks. Firstly, for efficiency purposes, the visual vocabulary is commonly constructed by directly clustering the low-level visual feature vectors extracted from local keypoints, without considering the high-level semantics of images. That is, the visual BOW model still suffers from the semantic gap, and thus may lead to significant performance degradation in more challenging tasks (e.g. social image classification). Secondly, typically thousands of visual words are generated to obtain better performance on a relatively large image dataset. Due to such large vocabulary size, the subsequent image classification may take sheer amount of time. To overcome the first drawback, we develop a graph-based method for visual BOW refinement by exploiting the tags (easy to access although noisy) of social images. More notably, for efficient image classification, we further reduce the refined visual BOW model to a much smaller size through semantic spectral clustering. Extensive experimental results show the promising performance of the proposed framework for visual BOW refinement and reduction