Near Duplicate Detection-Based Image Spam Filters
Advances in information security, privacy, and ethics book series · 2017
A picture is worth a thousand words. Spam images give us many hints; one of them is that they are duplicates. Spam images are often generated from the same templates (which are designed by spammers) as they are sent to various recipients at the same time in batches. Various spam images are generated by randomization of the contents of these templates; as a result a similarity or uniqueness is present among the spam images. This similarity property in visually similar spam images can be exploited by the spam detectors for discriminating them from ham. The spam detectors can further trained on new data, if the spam images are generated from different templates, which is not a frequent phenomenon as it is resources intensive. The detection schemes that exploit the near duplicate characteristics of image spam, uses different types of image characteristics to calculate the similarity among spam images. This chapter provides the details of near duplicate detection based image spam filters, a literature review on these spam filters and their limitations.