Mohammad Ghanbari

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In this Letter hierarchical quadrature amplitude modulation (HQAM) is used to provide unequal error protection (UEP) for layered (data partitioned) H.264 coded video. In a conventional HQAM system, the high priority (HP) and low priority (LP) capacities have a constant ratio, whereas in H.264 data partitioning, the corresponding parts do not necessarily(More)
In this study, the authors introduce a highly efficient reversible data hiding system. It is based on dividing the image into tiles and shifting the histograms of each image tile between its minimum and maximum frequency. Data are then inserted at the pixel level with the largest frequency to maximise data hiding capacity. It exploits the special properties(More)
— 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)
A low bit rate video coding technique that uses spatio-temporal geometric transforms is presented. Motion compensation based on the bilinear transform is employed to reduce the temporal redundancy of the video. The spatial redundancy of the motion compensated error images is reduced by a combination of Fractal and DCT. It is shown that in the objects(More)
We propose a new adaptive algorithm for semi-automatic video object segmentation based on joint pixel features using the undecimated wavelet packet transform (UWPT) and luminance value. The method starts with the object's boundary specification at the reference frame assisted by the user. After selecting a set of feature points which approximate the(More)
— In this paper we evaluate the performance of layered (data partitioned and SNR scalable) H.264/AVC video small contribution to the quality of the image. Based on these observations, we propose a novel adaptive turbo-code with a temporal diversity scheme for transmitting a video stream encoded by SNR scalable H.264.
Tracking of video objects in pixel space using block based methods or template matching suffers from boundary alignment problems, assumes knowledge of object location, and is severely effected by rotation and shear. This paper suggests a region domain based object tracking algorithm. Using region adjacency graphs it is proposed to perform the search in(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)
—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)