Resolution Scalability Research Articles

Highly scalable, low-complexity image coding using zeroblocks of wavelet coefficients

We propose a new highly scalable wavelet transform-based image coder, called S-SPECK, on the extension of a well-known zero-block image coder SPECK, by achieving not only distortion scalability, resolution scalability, and region of interest (ROI) retrievability, but also excellent compression performance with very low computational complexity. Though new features have been introduced into S-SPECK, our coder is quite competitive with SPECK on compression performance (peak signal-to-noise ratio) and computational complexity (encoding and decoding times) at various bit rates for standard test images. A novel quality layer formatting method is implemented in S-SPECK, which is much simpler and faster than PCRD used in JPEG2000. Extensive experiments have verified all our claims for S-SPECK.

Spatially scalable resolution image coding method with memory optimization based on wavelet transform

This letter exploits fundamental characteristics of a wavelet transform image to form a progressive octave-based spatial resolution. Each wavelet subband is coded based on zeroblock and quardtree partitioning ordering scheme with memory optimization technique. The method proposed in this letter is of low complexity and efficient for Internet plug-in software.

A layered naming architecture for the internet

Currently the Internet has only one level of name resolution, DNS, which converts user-level domain names into IP addresses. In this paper we borrow liberally from the literature to argue that there should be three levels of name resolution: from user-level descriptors to service identifiers; from service identifiers to endpoint identifiers; and from endpoint identifiers to IP addresses. These additional levels of naming and resolution (1) allow services and data to be first class Internet objects (in that they can be directly and persistently named), (2) seamlessly accommodate mobility and multi-homing and (3) integrate middleboxes (such as NATs and firewalls) into the Internet architecture. We further argue that flat names are a natural choice for the service and endpoint identifiers. Hence, this architecture requires scalable resolution of flat names, a capability that distributed hash tables (DHTs) can provide.

Scalable motion vector coding

Recently proposed scalable wavelet-based video codecs using spatial-domain motion compensated temporal filtering (SDMCTF) offer competitive compression performance when compared to H.264 and generate embedded bit-streams supporting quality, resolution and temporal scalability. To be able to support a large range of bit-rates with optimal compression efficiency, these codecs require a quality-scalable motion vector coding technique. Such an algorithm based on the integer wavelet transform followed by embedded coding of the wavelet coefficients was proposed in the recent past. In this paper, we present a quality-scalable motion vector coding algorithm using median-based motion vector prediction. The compression performance of the proposed algorithm is compared to that of the wavelet-based technique and is found to be superior. Additionally, the proposed motion vector codec is incorporated into an SDMCTF-based video codec and the benefits of using quality-scalable motion vector representations are experimentally demonstrated.

MESHGRID—A Compact, Multiscalable and Animation-Friendly Surface Representation

MESHGRID is a novel, compact, multiscalable and animation-friendly surface representation method, which has been introduced in MPEG-4 . The MESHGRID representation attaches a description of the "global connectivity" between the vertices on the object's surface (i.e., the 3-D connectivity wireframe) to a regular 3-D grid of points (i.e., the reference grid). MESHGRID efficiently encodes the 3-D connectivity wireframe by using a new type of 3-D extension of Freeman chain-code. MESHGRID does not explicitly store the polygons of the surface, since the 3-D connectivity wireframe has particular connectivity properties allowing for the unambiguous derivation of the triangulation. The reference grid is a smooth vector field defined on a regular discrete 3-D space. This grid is efficiently compressed by using an embedded 3-D wavelet-based multiresolution intra-band coding algorithm. MESHGRID can be efficiently exploited for QoS since it allows for three types of scalability in both view-dependent and view-independent scenarios, including: 1) resolution scalability, i.e., the adaptation of the number of transmitted vertices; 2) shape precision, i.e., the adaptive reconstruction of the reference grid positions; and 3) vertex position scalability, i.e., the change of the precision of known vertex positions with respect to the reference grid. Furthermore, in addition to the classical vertex-based animation, MESHGRID also supports specific animation capabilities, such as: 1) rippling effects by changing the position of the vertices relative to corresponding reference grid points and 2) reshaping on a hierarchical basis of the regular reference grid and its attached vertices.

Quadtree-Based Multiregion Multiquality Image Coding

Region-based video coding schemes employed in MPEG-4 are also promising for still image coding applications where images contain a number of objects that can be encoded at different bit rates, such as compression of medical images for archiving and transmission. Motivated by this fact, in this letter we investigate multiregion multiquality (MRMQ) coding with quadtree-based wavelet coders. We present a novel scheme which addresses the region size sensitivity problem in region-based coding. The proposed method outperforms the region-of-interest (ROI) coding unit of JPEG-2000; it is possible to save 0.3 bits per pixel to attain the same ROI/background fidelity without sacrificing the additional features provided by JPEG-2000, such as resolution scalability and error resilience.

Progressive coding of error-diffused bilevel images

We propose a new method to compress error-diffused bilevel images with resolution scalability. This method is a combina- tion of inverse halftoning and rehalftoning. For the inverse halfton- ing, we combine 232 dots into a single pixel of a resolution-reduced image, where each pixel has a multilevel value of 0, 1, 2, 3, and 4. After the inverse halftoning, the resolution-reduced multilevel image is halftoned by using an error diffusion algorithm. Thus, the resolu- tion of the error-diffused bilevel images can be reduced by repetition of the inverse halftoning and rehalftoning processes. After reducing the image size, we encode an error-diffused bilevel image progres- sively from the lowest resolution image to the highest resolution image. To encode higher resolution images, we use the information in the previously coded lower resolution image. Though the com- pression ratios of the proposed algorithm are similar to those of progressive Joint Bilevel Image Processing Group (JBIG), the image quality of the resolution-reduced image from the proposed algorithm is much better than that from the progressive JBIG. © 2003 SPIE

A full-featured, error-resilient, scalable wavelet video codec based on the set partitioning in hierarchical trees (SPIHT) algorithm

Compressed video bitstreams require protection from channel errors in a wireless channel. The 3-D set partitioning in hierarchical trees (SPIHT) coder has proved its efficiency and its real-time capability in the compression of video. A forward-error-correcting (FEC) channel (RCPC) code combined with a single automatic-repeat request (ARQ) proved to be an effective means for protecting the bitstream. There were two problems with this scheme: (1) the noiseless reverse channel ARQ may not be feasible in practice and (2) in the absence of channel coding and ARQ, the decoded sequence was hopelessly corrupted even for relatively clean channels. We eliminate the need for ARQ by making the 3-D SPIHT bitstream more robust and resistant to channel errors. We first break the wavelet transform into a number of spatio-temporal tree blocks which can be encoded and decoded independently by the 3-D SPIHT algorithm. This procedure brings the added benefit of parallelization of the compression and decompression algorithms, and enables implementation of region-based coding. We demonstrate the packetization of the bitstream and the reorganization of these packets to achieve scalability in bit rate and/or resolution in addition to robustness. Then we encode each packet with a channel code. Not only does this protect the integrity of the packets in most cases, but it also allows detection of packet-decoding failures, so that only the cleanly recovered packets are reconstructed. In extensive comparative tests, the reconstructed video is shown to be superior to that of MPEG-2, with the margin of superiority growing substantially as the channel becomes noisier. Furthermore, the parallelization makes possible real-time implementation in hardware and software.

Motion-compensated layered video coding for playback scalability

We propose a multilayered video coding scheme based on motion estimation which enables a decoder to dynamically change its temporal and spatial resolution during playback. In the proposed scheme, a new motion-prediction structure with a temporal hierarchy of frames is adopted to afford temporal resolution scalability and the wavelet decomposition with a new intra-update algorithm is used to offer spatial scalability. Experimental results show that the proposed scheme exhibits a higher compression ratio than conditional replenishment schemes because it further reduces the temporal redundancy using motion estimation. Also the proposed intra-update technique enables adaptation to dynamic change of spatial resolution with the effective follow-up of prediction in the decoder while preventing the large peaks in bit rate. Therefore, the proposed scheme is expected to be effectively used in heterogeneous environments such as the Internet, ATM, and wireless networks where dynamic scalability and interoperability are required.

Motion-compensated video compression with reduced complexity encoding for remote transmission

Abstract Efficient operation at very low bit-rates necessitates a complex encoder that can exploit both spatial and temporal redundancy in a video sequence. To reduce the complexity of such an encoder, we introduce here a new form of motion compensation similar to the conventional hybrid DPCM-transform method but where the compensation is performed outside the feedback loop. In addition to reducing encoder complexity, the proposed out-of-loop (OOL) compensation scheme also supports resolution and frame-rate scalability. While the basic idea is conceptually similar to the pan compensation proposed by Taubman and Zakhor, our method continually tracks and updates the image in the feedback loop in the same way as the conventional DPCM coder. Using OOL compensation, we have observed an average encoder speed increase of 33% on a typical CIF-size video sequence compared to the conventional approach with no significant decrease in decoder speed. Furthermore, we have also found that OOL pan compensation significantly improves the rate-distortion performance of the system relative to conventional pan compensation – taken over five different video sequences, the average bit-rate reduction is 9.2% and the average mean-squared error reduction is 29.6%.

A practical current sensing technique for I/sub DDQ/ testing

In this paper, a practical design for built-in current sensors (BICS's) is proposed. This scheme can execute current testing during the normal circuit operation with very small impact on the performance of the circuit under test (CUT). In addition, scalable resolutions and no external voltage/current reference make this design more effective and efficient than previous designs. Moreover this scheme can be used to monitor the current-related faults of both CMOS and non-CMOS circuits. Thus it is highly suitable for design for testability (DFT) on a multiple-chip module (MCM) or to be the current monitor on the test fixture under the quality test action group (QTAG) standard.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Optimal image formats for advanced television and the NII

AbstractVarious high‐definition television (HDTV) and advanced television (ATV) scanning parameter sets have been proposed, including the “Grand Alliance” proposal before the U.S. Federal Communications Commission. However, the American Society of Cinematographers has recommended that the proposed 16:9 aspect ratio should be replaced by a simpler and more pleasing 2:1 aspect ratio. Various proposed and existing formats of interest include 640 × 480, 864 × 648, 1024 × 768, 1152 × 864, and 1280 × 1024 for computer screens, and widescreen formats at or near 2 megapixels. When these formats are analyzed in the context of forming the basis for a suitable hierarchy of scalable resolutions and temporal rates with this new aspect ratio in mind, some significant patterns emerge. Certain fundamental issues in constructing a convenient hierarchy include progressive scanning (no interlace), square pixels (or simple squeezes), and a simple fractional relationship between members of the hierarchy, both temporally and in resolution. There is also a need to exceed 70 Hz in display rate for the wide, bright screens of HDTV/ATV. There is great value in compatibility with computer displays, which exceed 70 Hz with various common resolutions in today's ubiquitous 4:3 aspect ratio. The development of a national and global information infrastructure (NIL/GII) would benefit greatly from such commonality of computer and HDTV/ATV formats. There will be a need for every display to present the richest possible image quality in support of the presentation of text, graphics, and still images, as well as our national and world hertage of high‐resolution films. It will also be necessary to develop guidelines for the composition of images and text by taking into account the common display formats which will be available. This is done by understanding the common “safe area” throughout the variety of existing and future displays, and by considering legibility on each. The best possible architecture for digital HDTV/ATV for the United States and internationally will be needed to support the major NII/GII applications, including health care, library access, education, collaborative and remote work, interactive news, on‐line commerce, and many other uses in addition to entertainment..©1994 John Wiley &amp; Sons Inc

Optical oversampled analog-to-digital conversion

A new approach to optical analog-to-digital (A/D) conversion based on oversampling and interpolative coding techniques is described, and both interferometric and noninterferometric architectures based on this method are presented. This new approach combines the high resolution of classical oversampled A/D conversion with the high speed of optical processing technology to extend the resolution and conversion rates beyond that currently possible with other electronic or optical converters. The proposed optical converters are simple, consisting of multiple quantum well self-electro-optic effect devices, photodetectors, and common optical components that are capable of operating at sampling rates of up to 15 Gbits/s and that can provide scalable resolutions of 16 and 8 bits at a conversion rate of 117 and 938 MHz, respectively.

An Example Hierarchy of Formats for HDTV

Various HDTV scanning parameter sets have been proposed. When these parameters are analyzed in the context of forming the basis of a suitable hierarchy of scalable resolutions and temporal rates, some significant patterns emerge. Certain fundamental issues in constructing a convenient hierarchy include progressive scanning, square pixels (or simple squeezes), and a simple fractional relationship between members of the hierarchy, both temporally and in resolution.