Study On The Quantum Color Images Processing Algorithm

In classic computers, there are two main ideas to implement images’ security:image encryption technology, and authentication based on digital watermarkingtechnology; The former does not support images’ share, it can encrypt images beforetransmission through suitable encryption algorithm, its biggest drawback is that theinformation encrypted easily draw the attacker’s attention, and possible to be cracked,once cracked, the information will be transparent easily, especially cipher text doesnot allow a little modification, so this technology now is limited. Digitalwatermarking can be implemented by embedding digital data directly ontomultimedia objects such that it can be detected or extracted later. Because the digitalmediums are increasingly furnished on Internet in modern society, there is atremendous trend to use watermarking techniques on these mediums to prevent themfrom piracy, unauthorized usage and enable the tracking and conviction of mediapirates. However, once attacked, the watermark will not be extracted accurately, stillnot up to the aim of copyright protection.As the development of quantum, classical image processing is naturally extendedto the quantum scenario. As a new computing model, quantum computation can store,process, and transmit quantum information with characteristics of entanglement andsuperposition in quantum mechanics. Thanks to quantum mechanics which have theperfect principles, many problems cannot be achieved or inefficiency in classicalmechanics gets overthrown proven in quantum theory. This paper is based on thecombination of classical image processing algorithms and quantum theory.The main researching content of the article includes the following aspects:(1) This article investigates the quantum watermark method for quantum gray-scaleimages, which based on Quantum Fourier Transform presented by Zhang et.al[1].Thisalgorithm aimed to embed the quantum watermark image into the Fourier coefficientsof the quantum carrier image without affecting carrier image’s visual effect. But theprotocol was not clearly described, and some steps were ambiguous. More important,the author tried to perform an image-adding and subtraction operation to transfer tosuperposition on quantum position state, illustrated as:|Q p|QA|QB,|Q p|QA|QB, which forbidden by quantum mechanics’ principles. According tothe above, a possible improvement protocol is proposed. (2) A novel watermarking and authentication strategy for color images using quantumwavelet transform (QWT) is proposed. Similar to A. M. Iliyasu et al s protocol[2], itis secure, keyless and blind. An introduction of quantum image addition andsubtraction operation is given, and then gives the proposed watermarking andauthentication protocol; At last a detailed theoretical analysis is described to clarify itscomputational complexity, robustness and advantages over its classical counterparts.It paves the way for introducing more frequency domain transforms into quantum dataprotection.(3) This article proposes an encryption/decryption method for color images, whichutilizes Quantum Fourier Transform and double random-phase encoding technique.The encryption process can be realized by performing two secret random-phaseencoding operations in both the input and the QFT planes respectively. We know that,in quantum computation, all operations are invertible, so our decryption process is theinverse of the encryptions’. Detailed numerical simulation and theoretical analysis aregiven to clarify its computational complexity, robustness and advantages over itsclassical counterparts. It opens the door for introducing encryption of color imagesinto quantum scenarios.