System for Screening Objectionable Images
James Ze Wang, Jia Li, Gio Wiederhold, Oscar Firschein
Stanford University, Stanford, CA 94305
Abstract:
As computers and Internet become more and more available to families,
access of objectionable graphics by children is increasingly a problem
that many parents are concerned about. This paper describes
WIPE(TM) (Wavelet Image Pornography Elimination), a system
capable of classifying an image as objectionable or benign. The
algorithm uses a combination of an icon filter, a graph-photo
detector, a color histogram filter, a texture filter, and a
wavelet-based shape matching algorithm to provide robust screening of
on-line objectionable images. Semantically-meaningful feature vector
matching is carried out so that comparisons between a given on-line
image and images in a pre-marked training data set can be performed
efficiently and effectively. The system is practical for real-world
applications, processing queries at the speed of less than 2 seconds
each, including the time to compute the feature vector for the query,
on a Pentium Pro PC. Besides its exceptional speed, it has
demonstrated 96% sensitivity over a test set of 1,076 digital
photographs found on objectionable news groups. It wrongly classified
9% of a set of 10,809 benign photographs obtained from various
sources. The specificity in real-world applications is expected to be
much higher because benign on-line graphs can be filtered out with our
graph-photo detector with 100% sensitivity and nearly 100%
specificity, and surrounding text can be used to assist the
classification process.
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Citation:
James Z. Wang, Jia Li, Gio Wiederhold and Oscar Firschein, ``System
for Screening Objectionable Images,'' Computer Communications,
vol. 21, no. 15, pp. 1355-1360, Elsevier, 1998.
Copyright 1998
Journal Computer Communications, Elsevier, Amsterdam, 1998.
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Last Modified:
28-Jan-98 23:20:32 PST
© 1998, James Z. Wang