In this paper, we propose a noise filtering scheme, which is based on a multichannel homomorphic transformation, for color photographic images corrupted by signal–dependent film grain noise. The proposed method performs the estimation of the noise parameter using the higher–order statistics (skewness or kurtosis) of the corrupted image and the filtered image statistics. This parameter estimatio...

Performance of the face verification system depend on many conditions. One of the most problematic is varying illumination condition. In this paper 14 normalization algorithms based on histogram normalization, illumination properties and the human perception theory were compared using 3 verification methods. The results obtained from the experiments showed that the illumination preprocessing me...

It is well known that even slight changes in nonuniform illumination lead to a large image variability and are crucial for many visual tasks. This paper presents a new ICA related probabilistic model where the number of sources exceeds the number of sensors to perform an image segmentation and illumination removal, simultaneously. We model illumination and reflectance in log space by a generali...

In this paper, we propose a novel technique to reconstruct 3D surface of an underwater object using stereo images. Reconstructing the 3D surface of an underwater object is really a challenging task due to degraded quality of underwater images. There are various reason of quality degradation of underwater images i. e. , non-uniform illumination of light on the surface of objects, scattering and ...

In this paper, we combined with efficient image signal processing algorithms, according to the manifestations of the blur of polish operation in the frequency domain,proposed a blind detection algorithm for image tampering evidence. First, the target image transformed into a new Nonsubsampled dyadic contourlet domain which based on contrast à trous wavelet, then homomorphic filtering on it in t...

Recommender systems are widely used in online applications since they enable personalized service to the users. The underlying collaborative filtering techniques work on user’s data which are mostly privacy sensitive and can be misused by the service provider. To protect the privacy of the users, we propose to encrypt the privacy sensitive data and generate recommendations by processing them un...

Homomorphic encryption enables computations on encrypted data. This property makes such encryption schemes useful in a wide variety of privacy preserving applications. This paper provides a brief survey on the homomorphic encryption. We describe the homomorphic cryptosystems from partially homomorphic encryption to fully homomorphic encryption. We also give some security analysis and describe h...

In this paper we consider the description of homomorphic and fully homomorphic ciphers in the p-adic model of encryption. This model describes a wide class of ciphers, but certainly not all. Homomorphic and fully homomorphic ciphers are used to ensure the credibility of remote computing, including cloud technology. The model describes all homomorphic ciphers with respect to arithmetic and coord...

Bid opening in sealed-bid e-auction is efficient when a homomorphic encryption algorithm is employed to seal the bids and homomorphic bid opening is employed to open the bids. Such e-auction schemes are called homomorphic auctions. However, high efficiency of homomorphic auctions is based on an assumption: the bids are valid (e.g. within a special range). An undetected invalid bid can compromis...