The quality of a television system is significantly determined by the amount of distortions within the displayed image. One of these distortions is white Gaussian noise. So a spatio-temporal algorithm for reducing noi...
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The quality of a television system is significantly determined by the amount of distortions within the displayed image. One of these distortions is white Gaussian noise. So a spatio-temporal algorithm for reducing noise in interlaced video is presented in this paper. It consists of a detail preserving spatial algorithm which uses a set of contour oriented lowpass-filters that are controlled via corresponding highpass masks. The influence of the number of different masks as well as of the coefficients are analyzed. The temporal scheme works in two subbands and makes use of some perception properties of the human eye. The high efficiency of this cascaded system is proved by simulations.
We experimentally demonstrate 100-m-long image fiber transmission of four-channel multiplexed two-dimensional signals. To upgrade the system throughput, we study several hundred Gb/s-class 2-D optical parallel data li...
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We experimentally demonstrate 100-m-long image fiber transmission of four-channel multiplexed two-dimensional signals. To upgrade the system throughput, we study several hundred Gb/s-class 2-D optical parallel data link using an image fiber for the transmission and 2-D arrays of vertical-cavity surface-emmitting laser diodes (VCSELs) and p-i-n photo-diodes (PDs) as the transmitter and the receiver respectively. This system employs space code division multiple access (Space-CDMA) to multiplex 2-D optical parallel signals. To establish multi-channel optical link between 2-D VCSEL array and PD array with a high alignment precision and a good repeatability, we develop a novel visual alignment technique using a micro-optic image fiber coupler, which consists of miniature cube beamsplitter and graded index (GRIN) rod lenses. The effectiveness of the visual alignment with the image fiber coupler is experimentally demonstrated. This result will encourage the application of optical space-CDMA using an image fiber and 2-D arrays of VCSELs and PDs to future high-throughput 2-D parallel data links connecting massively parallel processors.
Digital terrains are generally large files and need to be simplified to be rendered efficiently. We propose to build an adaptive embedded triangulation based on a binary tree structure to generate multiple levels of d...
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Digital terrains are generally large files and need to be simplified to be rendered efficiently. We propose to build an adaptive embedded triangulation based on a binary tree structure to generate multiple levels of details. We present a O(nlogn) decimation algorithm and a O(nlogn) refinement algorithm, where n is the number of elevation points. We compare them in a rate-distortion (RD) framework. The algorithms are based on an improved version of the optimal tree pruning algorithm G-BFOS allowing one to deal with constrained tree structures and non-monotonic tree functionals.
We describe a new approach to animating generic 3D wireframe models of human heads using MPEG-4 synthetic/natural hybrid coding (MPEG4/SNHC) facial definition parameters (FDP) points and facial animation parameters (F...
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ISBN:
(纸本)0818688211
We describe a new approach to animating generic 3D wireframe models of human heads using MPEG-4 synthetic/natural hybrid coding (MPEG4/SNHC) facial definition parameters (FDP) points and facial animation parameters (FAP) streams. The FDP points are used to partition a head model into sections that have approximately conforming motion with human muscles. Using the borders of these sections as features, a 3D morphing algorithm is developed to morph vertices from one frame to the next while preserving the qualities of facial expressions such as those of human visual speech. A comparison is made with the facial animation table (FAT) approach proposed in MPEG-4/SNHC. Experimental results on standard FAP sequences and on a proprietary system are shown.
Content based indexing and retrieval of images and video requires a proper semantic description for image content. The paper discusses the mapping of high level, application specific features to the visual primitives ...
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Content based indexing and retrieval of images and video requires a proper semantic description for image content. The paper discusses the mapping of high level, application specific features to the visual primitives that are accessible through imageprocessing techniques. A major difficulty is that there are currently no established methodologies for describing the contents of an image in terms of semantic features, and we suggest that semiotic approaches could be adapted to the task of image description in limited areas of expertise. After reviewing current trends in the mapping of high level to low level features, we present preliminary results that suggest a possible strategy for mapping semiotic descriptions to imageprocessing primitives.
We consider the problem of coding video signals using motion compensation and a forward coded dense motion field. First, we develop a motion estimation technique that yields dense estimates suitable for the coding app...
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ISBN:
(纸本)0818688211
We consider the problem of coding video signals using motion compensation and a forward coded dense motion field. First, we develop a motion estimation technique that yields dense estimates suitable for the coding application; next, we develop a prototype of a video coder, which we use to verify that high coding performance is attainable within our framework. To find our sought motion estimates, we assume motion in an observed image sequence to be a stochastic process, modeled as a Markov random field (MRF). The standard maximum a posteriori (MAP) estimation problem with MRF priors is formulated as a constrained optimization problem (where the constraint is on the entropy of the sought estimate), but then transformed into a classical MAP estimation problem, and solved using standard techniques. A key advantage of the constrained formalization is that, in the process of transforming it back to the classical framework, parameters which in the classical framework are left unspecified (and often tweaked in an experimental stage) become now uniquely determined by the introduced entropy constraint. To verify that our motion estimates are indeed useful for coding, we compare the performance of a prototype video coder with that of an equivalent coder based on block-matching motion estimates. Experimental results reveal, for various types of video signals and at various rates, that: (a) in terms of PSNR, our system equals or improves upon the performance of full search block matching; and (b) in terms of visual quality our improvements are significant, since our images are completely free of blocking artifacts.
Operation of AUVs or other platforms that rely upon robust communications for navigation and mission critical tasks is facilitated by the use of on-board data compression. Data compression eliminates redundancy of tra...
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Operation of AUVs or other platforms that rely upon robust communications for navigation and mission critical tasks is facilitated by the use of on-board data compression. Data compression eliminates redundancy of transmitted information and therefore improves the efficiency of the entire mission. In some applications, acoustic and non-acoustic sensor information is acquired and processed to produce a visual representation for ease of human-in-the-loop analysis and interpretation. Many image and data compression methods are currently in development. Emphasis has been placed on achieving high efficiency as characterized by compression ratio while retaining the least error between the original image and the compressed image. Although some algorithms produce excellent results, computational complexity, and hence speed of compression or decompression, can become a limiting factor in real-time use depending upon the capability of the on-board processor. This paper describes the implementation of a high performance image compression transform using a dedicated DSP processor and supporting computer host. The system architecture and strategy for efficient code implementation are described. Example performance measures are presented for non-acoustic undersea studies. Future plans and developments for specialized applications are also discussed.
In this paper, some of the most significant image quality indexes are reviewed and compared with a new method for blockness distortion evaluation. The paper begins with a brief survey on classical measures based on nu...
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ISBN:
(纸本)0780339061
In this paper, some of the most significant image quality indexes are reviewed and compared with a new method for blockness distortion evaluation. The paper begins with a brief survey on classical measures based on numerical difference between original and reconstructed image data (e.g., MSE, SNR and PSNR) and advanced methods aiming at considering the perceptive aspects of image degradation (e.g., Hosaka Plots and other methods based on Human visual System properties like Information Content or Perceptual image Distortion). After, four innovative methods for blockness distortion measurement are proposed: two based on DCT analysis, and two on differential Sobel operator. Results on standard pictures confirm the efficiency of the proposed measures.
Fractal image compression is computationally expensive. Therefore speedup techniques are required to achieve time demands comparable to other compression techniques. In this paper we combine sequential and parallel te...
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ISBN:
(纸本)0819424358
Fractal image compression is computationally expensive. Therefore speedup techniques are required to achieve time demands comparable to other compression techniques. In this paper we combine sequential and parallel techniques suitable for MIMD architectures which moves this compression scheme closer to real-time processing. The algorithms introduced are especially designed for memory-critical environments.
Global motion estimation and compensation are important research issues in video compression. The main difficulty in global motion estimation resides in the disturbance of independently moving objects. The algorithm p...
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ISBN:
(纸本)0819424358
Global motion estimation and compensation are important research issues in video compression. The main difficulty in global motion estimation resides in the disturbance of independently moving objects. The algorithm presented in this paper exploits global motion information not only from stationary objects and the image background, but also from independently moving objects. Simulation results show that the new algorithm is more robust to the disturbance of independently moving objects, and computationally faster than an algorithm based on least-square approximation.
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