NBNN-DF: NBNN WITH DISCRIMINATIVE FEATURES

by OSung Kwon, JungIn Lee, and Sung-eui Yoon.

KAIST Tech. Report (CS-TR-2012-371)
(Submitted to ICME 2013)

This figure shows the overall flow of NBNN-DF.

Abstract

We propose a novel, Na¡§©¥ve Bayes Nearest Neighbor (NBNN) classifier considering Discriminative Features, NBNN-DF, for improving both classification accuracy and query-time performance. Unlike the original NBNN method, we define discriminative features among all the descriptors extracted from training and query images, and perform NBNN with those discriminative features. To define discriminative features we measure a discriminative power for each feature based on a ratio of posterior probability that the feature is located in its positive class to that in its negative class. While it is easy to measure discriminative power for features extracted from training images, we face the chicken-and-egg problem for a query image, whose class type is unknown. To address this problem we hypothesize potential class types of the query image and perform NBNN with discriminative features under its hypothetical classes, while considering a confidence level of each hypothesis. We have tested our method on the Caltech101 dataset, and compared it against other stateof- the-art techniques. We found that our method, NBNNDF, achieves up to 34% relative accuracy improvement over prior techniques. Our technique achieves this improvement, while improving the overall query-time performance by using a smaller number of features.

Contents

Paper: NBNN-DF: NBNN WITH DISCRIMINATIVE FEATURES,
KAIST Tech. Report (CS-TR-2012-371), 2012 (Submitted to ICME 2013)

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