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Image and video compression algorithms based on recovery techniques using mean field annealing
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| Pengarang | : | - |
| Nama Majalah/Jurnal | : | Proceedings of the IEEE |
| Volume / Edisi | : | 83-2, FEBRUARY (No. 2) |
| Halaman | : | 304-316 |
| Abstrak | : | Image and video coding algorithms have found a number of applications ranging from video telephony on the public switched telephone networks (PSTN) to HDTV. However, as the bit rate is lowered, most of the existing techniques, as well as current standards, such as JPEG, H. 261, and MPEG-1 produce highly visible degradations in the reconstructed images primarily due to the information loss caused by the quantization process. In this paper, we propose an iterative technique to reduce the unwanted degradations, such as blocking and mosquito artifacts while keeping the necessary detail present in the original image. The proposed technique makes use of a priori information about the original image through a nonstationary Gauss-Markov model. Utilizing this model, a maximum a posteriori (MAP) estimate is obtained iteratively using mean field annealing. The fidelity to the data is preserved by projecting the image onto a constraint set defined by the quantizer at each iteration. The proposed solution represents an implementation of a paradigm we advocate, according to which the decoder is not simply undoing the operations performed by the encoder, but instead it solves an estimation problem based on the available bitstream and any prior knowledge about the source image. The performance of the proposed algorithm was tested on a JPEG, as well as on an H.261-type video codec. It is shown to be effective in removing the coding artifacts present in low bit rate compression. |
Neural network approaches to image compression
| Pengarang | : | - |
| Nama Majalah/Jurnal | : | Proceedings of the IEEE |
| Volume / Edisi | : | 83-2, FEBRUARY (No. 2) |
| Halaman | : | 288-303 |
| Abstrak | : | This paper presents a tutor a overview of neural networks as signal processing tools for image compression. They are well suited to the problem of image compression due to their massively parallel and distributed architecture. Their characteristics are analogous to some of the features of our own visual system, which allow us to process visual information with much ease. For example, multilayer perceptions can be used as nonlinear predictors in differential pulse-code modulation (DPCM). Such predictors have been shown to increase the predictive gain relative to a linear predictor. Another active area of research is in the application of Hebbian learning to the extraction of principal components, which are the basis vectors for the optimal linear Karhunen-Loeve transform (KLT). These learning algorithms are iterative, have some computational advantages over standard eigendecomposition techniques, and can be made to adapt to changes in the input signal. Yet another model, the self-organizing feature map (SOFM), has been used with a great deal of success in the design of codebooks for vector quantization (VQ). The resulting codebooks are less sensitive to initial conditions than the standard LBG algorithm, and the topological ordering of the entries can be exploited to further increasing the coding efficiency and reducing the computational complexity. |
High compression image coding using an adaptive morphological subband decomposition
| Pengarang | : | S. Sunarto Ndaru Mursito |
| Nama Majalah/Jurnal | : | Proceedings of the IEEE |
| Volume / Edisi | : | 83-2, FEBRUARY (No. 2) |
| Halaman | : | 272-287 |
| Abstrak | : | A morphological subband decomposition with perfect reconstruction is proposed. Critical subsampling is achieved. The reconstructed images using this decomposition do not suffer from any ringing effect. In order to avoid poor texture representation by the morphological filters an adaptive subband decomposition is introduced. It chooses linear filters on textured regions and morphological filters otherwise. A simple and efficient texture detection criterion is proposed and applied to the adaptive decomposition. Comparisons to other coding techniques such as JPEG and linear subband coding show that the proposed scheme performs significantly better both in terms of PSNR and visual quality. |
Model-based image coding advanced video coding techniques for very low bit-rate applications
| Pengarang | : | - |
| Nama Majalah/Jurnal | : | Proceedings of the IEEE |
| Volume / Edisi | : | 83-2, FEBRUARY (No. 2) |
| Halaman | : | 259-271 |
| Abstrak | : | The paper gives an overview of model-based approaches applied to image coding, by looking at image source models. In these model-based schemes, which are different from the various conventional waveform coding methods, the 3-D properties of the scenes are taken into consideration. They can achieve very low bit rate image transmission. The 2-D model and 3-D model based approaches are explained. Among them, a 3-D model based method using a 3-D facial model and a 2-D model based method utilizing 2-D deformable triangular patches are described. Works related to 3-D model-based coding of facial images and some of the remaining problems are also described. |
JAGUAR: a fully pipelined VLSI architecture for JPEG image compression standard
| Pengarang | : | - |
| Nama Majalah/Jurnal | : | Proceedings of the IEEE |
| Volume / Edisi | : | 83-2, FEBRUARY (No. 2) |
| Halaman | : | 247-258 |
| Abstrak | : | In this paper, we describe a fully pipelined single chip VLSI architecture for implementing the JPEG baseline image compression standard. The architecture exploits the principles of pipelining and parallelism to the maximum extent in order to obtain high speed and throughput. The architecture for discrete cosine transform and the entropy encoder are based on efficient algorithms designed for high speed VLSI implementation. The entire architecture can be implemented on a single VLSI chip to yield a clock rate of about 100 MHz which would allow an input rate of 30 frames per second for 1024/spl times/1024 color images. |
VLSI architectures for video compression-a survey
| Pengarang | : | - |
| Nama Majalah/Jurnal | : | Proceedings of the IEEE |
| Volume / Edisi | : | 83-2, FEBRUARY (No. 2) |
| Halaman | : | 220-246 |
| Abstrak | : | The paper presents an overview on architectures for VLSI implementations of video compression schemes as specified by standardization committees of the ITU and ISO. VLSI implementation strategies are discussed and split into function specific and programmable architectures. As examples for the function oriented approach, alternative architectures for DCT and block matching will be evaluated. Also dedicated decoder chips are included Programmable video signal processors are classified and specified as homogeneous and heterogenous processor architectures. Architectures are presented for reported design examples from the literature. Heterogenous processors outperform homogeneous processors because of adaptation to the requirements of special, subtasks by dedicated modules. The majority of heterogenous processors incorporate dedicated modules for high performance subtasks of high regularity as DCT and block matching. By normalization to a fictive 1.0 /spl mu/m CMOS process typical linear relationships between silicon area and through-put rate have been determined for the different architectural styles. This relationship indicates a figure of merit for silicon efficiency. |
Radiologic image compression-a review
| Pengarang | : | S. Wong |
| Nama Majalah/Jurnal | : | Proceedings of the IEEE |
| Volume / Edisi | : | 83-2, FEBRUARY (No. 2) |
| Halaman | : | 194-219 |
| Abstrak | : | The objective of radiologic image compression is to reduce the data volume of and to achieve a low bit rate in the digital representation of radiologic images without perceived loss of image quality. However, the demand for transmission bandwidth and storage space in the digital radiology environment, especially picture archiving and communication systems (PACS) and teleradiology, and the proliferating use of various imaging modalities, such as magnetic resonance imaging, computed tomography, ultrasonography, nuclear medicine, computed radiography, and digital subtraction angiography, continue to outstrip the capabilities of existing technologies. The availability of lossy coding techniques for clinical diagnoses further implicates many complex legal and regulatory issues. This paper reviews the recent progress of lossless and lossy radiologic image compression and presents the legal challenges of using lossy compression of medical records. To do so, we first describe the fundamental concepts of radiologic imaging and digitization. Then, we examine current compression technology in the field of medical imaging and discuss important regulatory policies and legal questions facing the use of compression in this field. We conclude with a summary of future challenges and research directions. |
Video on phone lines: technology and applications
| Pengarang | : | - |
| Nama Majalah/Jurnal | : | Proceedings of the IEEE |
| Volume / Edisi | : | 83-2, FEBRUARY (No. 2) |
| Halaman | : | 175-193 |
| Abstrak | : | This paper reviews the telephone loop plant characteristics, current DSL (digital subscriber line) technologies, recent efforts in video coding standards, and the interrelationship between DSL technologies and visual communications over subscriber lines. In overview of the loop plant characteristics we examine its physical makeup and transmission properties, where for the latter we discuss frequency and time responses of wire-pair lines and the impairments of echo, crosstalk, impulse noise, and radio frequency interference. We trace the historical development of various DSL technologies and comment on possible future evolution. Transmission technologies used in the ISDN basic-access DSL, the high bit-rate DSL, and the asymmetric DSL are portrayed. And the issue of spectrum compatibility among different transmission systems is explained. Several important video coding standards are briefly described, including ITU-T's H.261 and ISO's JPEG and MPEG series, which are either completed or emerging. The synergistic relationship between these standards and the DSL technologies is elucidated. As a result, DSL technologies provide the potential of delivering certain broadband services well in advance of direct fiber access for telephone subscribers. |
The Grand Alliance system for US HDTV
| Pengarang | : | K. Challapali |
| Nama Majalah/Jurnal | : | Proceedings of the IEEE |
| Volume / Edisi | : | 83-2, FEBRUARY (No. 2) |
| Halaman | : | 158-174 |
| Abstrak | : | The US HDTV process has fostered substantial research and development activity over the last several years. The Advisory Committee on Advanced Television Service (ACATS) was formed to advise the FCC on the technology and systems suitable for delivery of high definition service over terrestrial broadcast channels. Four digital HDTV systems where tested at the Advanced Television Testing Center. All the systems gave excellent performance, but the results were inconclusive and a plan for a second round of tests was prepared. As each of the four systems where being readied for retest. The proponents of the four individual digital HDTV proposals worked together to define a single HDTV system which incorporated the best technology from the individual systems. The consortium of companies, called the Grand Alliance (GA), announced a combined system and submitted it to ACATS for consideration. After ACATS certification, the GA began construction of a prototype system to submit for laboratory testing at the end of 1994. This paper describes the video compression subsystem and the hardware prototype. The preprocessing, motion estimation, quantization, and rate control subsystems are described. The system uses bidirectional motion compensation, discrete cosine transform, quantization and Huffman coding. The resulting bitstream is input into a transport system which uses fixed length packets. The multiplex transport stream is input into the 8-VSB transmission system. Finally, the specifics of the hardware implementation are described and some simulation results are presented. |
The development of an integrated audiovisual coding standard: MPEG
| Pengarang | : | - |
| Nama Majalah/Jurnal | : | Proceedings of the IEEE |
| Volume / Edisi | : | 83-2, FEBRUARY (No. 2) |
| Halaman | : | 151-157 |
| Abstrak | : | These days companies from many industry segments are moving towards the adoption of digital technology for upgrading existing or introducing new services. This unstoppable movement prompted by technological progress could have produced the digital replica of the existing incompatible systems put in place in the analog world. It is the merit of MPEG to have provided an integrated audiovisual coding standard to implement this epochal conversion from one technology to another while supporting a universal syntax representing audiovisual information that makes the standard usable for a variety of interoperable applications. The paper presents the approach followed in the development of the MPEG-1 and MPEG-2 standards and explains some of the basic technical elements. An overview of the current MPEG work is also given. |