Mohammad Ghanbari

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In this paper we propose a fast and efficient image retrieval method for searching JPEG2000 compressed image databases. Comparing image contents of the JPEG2000 coded images in the pixel domain requires image decompression, which imposes intensive computational processes of the inverse discrete wavelet transform and the arithmetic decoding. On the other(More)
In this paper we evaluate the performance of layered (data partitioned and SNR scalable) H.264/AVC video transmission using turbo-codes to provide unequal error protection (UEP) over Gaussian and Rayleigh fading channels. In UEP schemes, the more important layers have better error protection than the others. For instance, the base layer (or motion vectors)(More)
Multi-layered scalable bit-stream distribution requires protection for the rendering and transmission of its individual layers. This paper presents a sufficient encryption (SE) scheme for SVC layers which maintains the compression efficiency and the format compliancy of scalable bit-streams, without compromising the security. The purpose of SE is achieved(More)
Scalable multi-layered coded video requires its individual layer security, as every layer has its own characteristics i.e. bit-rate, frame rate, resolution and quality. We investigate a problem of individual layer cryptographic key management issues in scalable video coding (H.264/SVC) and propose a top down hierarchical keys generation and distribution(More)
Face recognition is a challenging problem due to variations in pose, illumination, and expression. Most techniques that can provide effective feature representation are based on wavelet transform. In this paper, an efficient feature extraction method based on DCT pyramid for face recognition is proposed. The DCT pyramid performed on each face image(More)
In this paper, a method for enhancing low contrast images is proposed. This method, called Gaussian Mixture Model based Contrast Enhancement (GMMCE), brings into play the Gaussian mixture modeling of histograms to model the content of the images. Based on the fact that each homogeneous area in natural images has a Gaussian-shaped histogram, it decomposes(More)