Histogram-based perceptual hashing for minimally changing video sequences

An increasing number of multimedia applications require techniques for efficient and automatic content identification and verification. Here, perceptual hashing technologies apply. Due to the diverseness of video data, algorithms whose design considers the properties of the different video classes are required. Therefore, different approaches exist to extract a perceptual hash. In this article, we propose a histogram-based perceptual hashing algorithm for minimally changing video sequences. The algorithm is described and the performed evaluation shows improvements of the identification performance for minimally changing video content

A novel algorithm for the development of perceptual hashes based on extraction of attributes of biometric characteristics

S napretkom računalnih i mrežnih tehnologija, količina digitalnih slika koje se prenose ili pregledavaju putem digitalnih uređaja eksponencijalno raste, a u porastu je neovlaštena uporaba kao i krivotvorenje istih. Ovaj doktorski rad bavi se percepcijskim sažetcima koji su „otisak” digitalne slike izveden iz različitih atributa njezina sadržaja, a upotrebljavaju se za provjeru autentičnosti ili identifikaciju digitalnih slika. Postoji mnogo područja njihove primjene: zaštita autorskih prava, računalna forenzika ili pretraživanje baza slika. Njihove su prednosti mala veličina, brzo pretraživanje i slanje putem mreže te robusnost na manipulacije i modifikacije. U disertaciji je razvijen novi algoritam za izradu percepcijskih sažetaka, koji izdvaja i analizira, koristeći se metodom modificirane census transformacije, lokalne atribute interesnih regija slika odnosno biometrijskih uzoraka, a u svrhu ispitivanja mogućnosti njegove upotrebe u biometriji. Napravljena je usporedba s drugim najčešće korištenim algoritmima te se utvrđuje hoće li novorazvijeni algoritam biti točniji i robusniji u području biometrijske autentikacije.With the advancement of computer and network technologies, the amount of digital images which are transferred or browsed through digital devices increases exponentially. However, unauthorized use and counterfeiting of the same also increases. This doctoral thesis deals with the perceptual hashes which are a "print" of a digital image derived from various attributes of its contents, and which are used for authentication or identification of digital images. There are many areas of their application: protection of copyrights, computer forensics or searching image databases. Perceptual hashes have several advantages, such as a small size, fast searching and sending via the network as well as the robusness to manipulation and modification. In this thesis, an algorithm for making perceptual hashes which extract and analyze attributes of region of interest in an image for the possibility of their use in biometrics using methods of modified census transformation has been developed. A comparison has been made with other commonly used algorithms and an improved robusness and precision of the newly developed algorithm for the purpose of biometric authentication will be determined

A novel algorithm for the development of perceptual hashes based on extraction of attributes of biometric characteristics

S napretkom računalnih i mrežnih tehnologija, količina digitalnih slika koje se prenose ili pregledavaju putem digitalnih uređaja eksponencijalno raste, a u porastu je neovlaštena uporaba kao i krivotvorenje istih. Ovaj doktorski rad bavi se percepcijskim sažetcima koji su „otisak” digitalne slike izveden iz različitih atributa njezina sadržaja, a upotrebljavaju se za provjeru autentičnosti ili identifikaciju digitalnih slika. Postoji mnogo područja njihove primjene: zaštita autorskih prava, računalna forenzika ili pretraživanje baza slika. Njihove su prednosti mala veličina, brzo pretraživanje i slanje putem mreže te robusnost na manipulacije i modifikacije. U disertaciji je razvijen novi algoritam za izradu percepcijskih sažetaka, koji izdvaja i analizira, koristeći se metodom modificirane census transformacije, lokalne atribute interesnih regija slika odnosno biometrijskih uzoraka, a u svrhu ispitivanja mogućnosti njegove upotrebe u biometriji. Napravljena je usporedba s drugim najčešće korištenim algoritmima te se utvrđuje hoće li novorazvijeni algoritam biti točniji i robusniji u području biometrijske autentikacije.With the advancement of computer and network technologies, the amount of digital images which are transferred or browsed through digital devices increases exponentially. However, unauthorized use and counterfeiting of the same also increases. This doctoral thesis deals with the perceptual hashes which are a "print" of a digital image derived from various attributes of its contents, and which are used for authentication or identification of digital images. There are many areas of their application: protection of copyrights, computer forensics or searching image databases. Perceptual hashes have several advantages, such as a small size, fast searching and sending via the network as well as the robusness to manipulation and modification. In this thesis, an algorithm for making perceptual hashes which extract and analyze attributes of region of interest in an image for the possibility of their use in biometrics using methods of modified census transformation has been developed. A comparison has been made with other commonly used algorithms and an improved robusness and precision of the newly developed algorithm for the purpose of biometric authentication will be determined