The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
This paper re-studies the security of an MPEG-video encryption scheme based on secret Huffman tables. The present cryptanalysis shows that: 1) the key space of the encryption scheme is not sufficiently large against divide-and-conquer (DAC) ciphertext-only attack; 2) its security against the chosen-plaintext attack is very weak. The insecurity is mainly due to the separated use of different Huffman...
This work develops and optimizes H.264/AVC video encoder on the TM320DM642 DSP platform. In order to transplant x264 source program onto the DSP and to accelerate the coding speed, a series of optimization methods have been proposed in this paper, including 2-D fast mode decision, sub-pixel optimization for motion estimation, and weighted matrix quantization. Furthermore, based on the architectural...
Two-level model averaging techniques have been proposed to construct the 3D reference template for the Drosophila brain. The surface-based reference template is suitable for integration of experimental data from different laboratories. The 3D distance transform is the most memory and time consuming part in the model averaging algorithm. With the improvement of microscopic scanning technology, images...
This paper studies different specifications of belief propagation for stereo analysis of seven rectified stereo night-vision sequences (provided by Daimler AG). As shown in [4], Sobel preprocessing of images has obvious impacts on improving disparity calculations. This paper considers other options of preprocessing (Canny and Kovesi-Owens edge operators), and concludes with a recommended setting for...
Super-resolution (SR) for video sequences is a technique to obtain a higher resolution image by fusing multiple low-resolution (LR) frames of the same scene. In a typical super-resolution algorithm, image registration is one of the most affective steps. The difficulty of this step results in the fact that most of the existing SR algorithms can not cope with local motions because they assume global...
Although the H.264 Deblocking Filter process is a relatively small piece of code in a software implementation, profile results shows it cost about a third of the total CPU time in the decoder. This work presents a high performance architecture for implementing a H.264 Deblocking Filter IP that can be used either in the decoder or in the encoder as a hardware accelerator for a processor or embedded...
In this paper, a universal steganalysis scheme for JPEG images based upon joint transform features is presented. We first analyzed two different transform domains (Discrete Cosine Transform and Discrete Wavelet Transform) separately, to extract features for steganalysis. Then a combination of these two feature sets is constructed and employed for steganalysis. A Fisher Linear Discriminant classifier...
A hardware design of shape-preserving contour tracing for objects in a segmented image for robot vision and pattern recognition applications is presented in this paper. The proposed contour tracing consists of two processes, namely progressive boundary linking (PBL) and synchronous redundancy pruning (SRP). The proposed method is realized on a System on Chip (SoC) with open-source processor IP core,...
Given a secret image I, a threshold r, and a set of n ( ≥ r) participants P = {1, 2, ... , n} with a set of weights W = {w1, w2, ... , wn} where wi is the weight (which indicates the degree/rank of importance) of participant i and we assume that w1 ≤ w2 ≤ ... w...
Image-based 3D model reconstruction method can use the same multi-view image sequence of the object for the generation of both the geometry model and texture map. Texture is very critical for virtual exhibition of 3D model and should be of high quality comparable to the geometry data. One problem is that the object surface may exhibit specular reflection of illuminated light. The texture extracted...
Channel bandwidth in 3G communication networks is very much limited for video telephony services. Therefore, it is worthwhile to enhance a subjective quality of video contents via ROI based coding. In this paper, An ROI/xROI based rate-control method is proposed, which considers the coding of both the ROI and the extended ROIs (xROI’s) in non-ROI to meet given target bitrates. In the proposed method,...
Distributed video coding (DVC) is an important topic for emerging applications, for example visual sensor networks and mobile video streaming. However, the major handicap applying DVC for real world applications is still the mandatory feedback channel. In previous approaches, the rate allocation algorithm was relying on feedback channel data. Commonly bit plane by bit plane decoding is done in a turbo...
The theory of Glass patterns naturally combines three essential aspects of painterly artworks: perception, randomness, and geometric structure. Therefore, it seems a suitable framework for the development of mathematical models of the visual properties that distinguish paintings from photographic images. With this contribution, we introduce a simple mathematical operator which transfers the microstructure...
This paper proposes a method for classifying 3D objects with similar appearances using different types of features from multi-view images. We can find this type of task in various practical applications, such as flaw inspection of industrial components, quality checking, ans screening of fruits and vegetables. In this paper, as an example such a concrete task, we will deal with the problem of classifying...
This article provides a simple and general way for defining the recovery rate of clustering algorithms using a given family of old clusters for evaluating the performance of the algorithm when calculating a family of new clusters. Under the assumption of dealing with simulated data (i.e., known old clusters), the recovery rate is calculated using one proposed exact (but slow) algorithm, or...
Recently, projector camera systems have been used actively for image synthesis and for 3D reconstruction. For using the projector camera systems in these applications, it is very important to compute the geometry between projectors and cameras accurately. Recently, it has been shown that by using the mutual projection of cameras, multiple cameras are calibrated quite accurately. However, this property...
Videos are composed of shots, each of which is recorded continuously by a camera, and video editing can be considered as a process of re-sequencing shots selected from original videos. Shots usually include redundant intervals, which are often edited out by professional editors. Defining the intact interval which is used in the edited video as the appropriate segment and all other intervals of equal...
Dermoscopy is one of the major imaging modalities used in the diagnosis of melanoma and other pigmented skin lesions. Due to the difficulty and subjectivity of human interpretation, automated analysis of dermoscopy images has become an important research area. Border detection is often the first step in this analysis. In this article, we present an approximate lesion localization method that serves...
Object segmentation and tracking are important techniques in video applications. In this paper, we present a novel system for active contour tracking of moving objects in video sequences. Our method includes preprocessing to identify an initial object contour, and object contour segmentation to refine the contour of the moving object. The edge flows and ant colony optimization are incorporated to...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.