Run-length Coding Research Articles

움직임 정보의 피드백을 갖는 선택적 블록 부호화에 기초한 분산 비디오 부호화 기법

Recently, DVC (Distributed Video Coding) techniques are drawing a lot of interests as one of the future research works to achieve low complexity encoding in various applications. But, due to the limited computational complexity, the performances of DVC algorithms are inferior to those of conventional international standard video coders, which use zig-zag scan, run length code, entropy code and skipped macroblock. In this paper, in order to overcome the performance limit of the DVC system, the distortion for every block is estimated when side information is found at the decoder and then we propose a new selective block encoding scheme which provides the encoder side with the motion information for the highly distorted blocks and then allows the sender to encode the motion compensated frame difference signal. Through computer simulations, it is shown that the coding efficiency of the proposed scheme reaches almost that of the conventional inter-frame coding scheme.

A new DC-free multimode code design with error correction capability for optical storage systems

DC-free run-length limited codes have been the cornerstone of all three generations of optical recording, CD, DVD and BD. Research into efficient coding methods is paramount for the upcoming fourth generation. A Multimode coding technique is an efficient coding method that has been reported in the literatures. Under multimode coding rules, a user word is translated into a plurality of possible candidate words, and among the candidate words the encoder selects the codeword with the least low-frequency spectral content. In our paper, we will present a new coding technique for constructing error correcting high-rate DC-free multimode code using a low-density parity-check (LDPC) code for future high-density optical recording. The scheme achieves reliable DC-suppression and obtains considerable bit error rate (BER) performance gain through the iterative decoding (or turbo equalization) with the concatenated detector.

A Modified Run-Length Coding for the Realization of Wavelet-based ECG Data Compression System

With high compression performance, realization of wavelet-based data compression system is crucial for multi-lead ECG signal recording. In this paper, a modified run-length coding (MRLC) algorithm associated with an efficient quantization scheme is proposed for the realization of a RRO-NRDPWT-based ECG data compression system. The MRLC with regularity and low computational complexity is suitable for hardware implementation at a cost of compression performance. This sacrifice will be compensated by the new quantization scheme. By using the MIT-BIH arrhythmia database, the experimental results show that the proposed scheme can be competitive to other wavelet-based approaches in compression performance. In addition, the MRLC can improve traditional run-length coding by about 13%.

Digital watermarking algorithm based on image feature point

It might fail to detect watermarking now that geometric attacks perform on a watermarked image and destroy the synchronization of the watermark signals embedded in the image.To restore the lost synchronism,a novel method to estimate the geometric operation using sifted Scale-Invariant Feature Transform(SIFT)was proposed.According to Sum of Squared Differences(SSD)of the pixels,the suitable feature points were refined to ensure robustness of the least-squares solution.The least squares iterative was convergent quickly,and the one step iteration would be able to get high accuracy geometric parameters;encoding binary watermark image by using Run-Length Code(RLC),watermarking was done by altering the coefficients of the DCT blocks corresponding to the value of RLC.The simulation results show that the proposed scheme achieves good image quality and it is robust to geometric attacks.

Adaptive-Compression Based Congestion Control Technique for Wireless Sensor Networks

Congestion in a wireless sensor network causes an increase in the amount of data loss and delays in data transmission. In this paper, we propose a new congestion control technique (ACT, Adaptive Compression-based congestion control Technique) based on an adaptive compression scheme for packet reduction in case of congestion. The compression techniques used in the ACT are Discrete Wavelet Transform (DWT), Adaptive Differential Pulse Code Modulation (ADPCM), and Run-Length Coding (RLC). The ACT first transforms the data from the time domain to the frequency domain, reduces the range of data by using ADPCM, and then reduces the number of packets with the help of RLC before transferring the data to the source node. It introduces the DWT for priority-based congestion control because the DWT classifies the data into four groups with different frequencies. The ACT assigns priorities to these data groups in an inverse proportion to the respective frequencies of the data groups and defines the quantization step size of ADPCM in an inverse proportion to the priorities. RLC generates a smaller number of packets for a data group with a low priority. In the relaying node, the ACT reduces the amount of packets by increasing the quantization step size of ADPCM in case of congestion. Moreover, in order to facilitate the back pressure, the queue is controlled adaptively according to the congestion state. We experimentally demonstrate that the ACT increases the network efficiency and guarantees fairness to sensor nodes, as compared with the existing methods. Moreover, it exhibits a very high ratio of the available data in the sink.

Distance-Enhancing Constrained Codes with Parity-Check Constraints for Data Storage Channels

This paper proposes efficient distance-enhancing constrained codes with parity-check (PC) constraints for data storage channels. We first propose simple and efficient finitestate encoding methods to design various distance-enhancing constrained codes, including a repeated minimum transition runlength (RMTR) code for optical recording channels, as well as a maximum transition run (MTR) code for magnetic recording channels. We further propose a general and systematic code design methodology, which can efficiently combine constrained codes with PC codes. The constrained codes can be any distanceenhancing constrained codes. The PC codes can be any linear binary PC codes. The rates of the designed codes are only a few tenths of a percent below the theoretical maximum. The proposed method enables soft information to be available to the PC decoder and soft decoding of PC codes. Examples of several newly designed distance-enhancing constrained PC codes are illustrated. Simulation results with blu-ray disc (BD) systems show that the proposed new RMTR code and RMTR constrained 4-bit PC code perform 0.2 dB and 0.85 dB better than the standard 17PP code, respectively, at error correction code (ECC) failure rate (EFR) of 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-12</sup> and high recording density.

A Novel $ {\rm x}$-ploiting Strategy for Improving Performance of Test Data Compression

A precomputed core test set contains a large number of don't cares ( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</i> 's) that can be effectively exploited to improve test data compression (TDC). Extending pattern run-length coding, we present a novel strategy that propagates the <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</i> 's of a reference pattern to a new reference pattern in such a way that the reference pattern is xor-ed with the pattern to be encoded. The <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</i> -propagating strategy can increase the probability of a reference pattern being coding-compatible with the pattern to be encoded, and its validity can be established by filling some <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</i> 's of the already encoded patterns in backtracing way. How our strategy is used for TDC is demonstrated. Experimental results for large ISCAS89 benchmarks show that, compared to the recently proposed schemes, our technique can effectively improve compression and simplify on-chip decoder, and work better when used for core-unified TDC.

Very Low Bit-Rate Video Coding by Combining H.264/AVC Standard and 2-D Discrete Wavelet Transform

In this paper, we propose a new method for very low bit-rate video coding that combines H.264/AVC standard and two-dimensional discrete wavelet transform. In this method, first a two dimensional wavelet transform is applied on each video frame independently to extract the low frequency components for each frame and then the low frequency parts of all frames are coded using H.264/AVC codec. On the other hand, the high frequency parts of the video frames are coded by Run Length Coding algorithm, after applying a threshold to neglect the low value coefficients. Experiments show that our proposed method can achieve better rate-distortion performance at very low bit-rate applications below 16 kbits/s compared to applying H.264/AVC standard directly to all frames. Applications of our proposed video coding technique include video telephony, video-conferencing, transmitting or receiving video over half-rate traffic channels of GSM networks.

Test data compression using extended frequency-directed run length code based on compatibility

A new test data compression method is presented. Based on the fact that adjacent test vectors in a test set have least incompatible bits, test vectors are grouped and amalgamated into a vector by assigning 1 or 0 to unspecified bits and c to incompatible bits. Extended frequency-directed run length based on compatibility (EFDR-BC) is used to encode the merged test vector. EFDR-BC can encode strings of 1s, 0s, and cs. The numbers of test vectors, incompatible bits and values of incompatible bits in a group make up the group head code. Experiments with the test sets of the ISCAS 89 benchmark circuit show that the method can achieve higher compression ratio.

Core-unified soc test data compression and application

The pattern run-length coding test data compression approach is extended by introducing don’t care bit (x) propagation strategy into it. More than one core test sets for testing core-based System-on-Chip (SoC) are unified into a single one, which is compressed by the extended coding technique. A reconfigurable scan test application mechanism is presented, in which test data for multiple cores are scanned and captured jointly to make SoC test application more efficient with low hardware overhead added. The proposed union test technique is applied to an academic SoC embedded by six large ISCAS’89 benchmarks, and to an ITC’ 02 benchmark circuit. Experiment results show that compared with the existing schemes in which a core test set is compressed and applied independently of other cores, the proposed scheme can not only improve test data compression/decompression, but also reduce the redundant shift and capture cycles during scan testing, decreasing SoC test application time effectively.

DIGITAL IMAGE COMPRESSION USING INTEGER BASEDTRANSFORM ALGORITHM

One of the most problems in computer application is the storage and transmission of images that makes the field of developing the image compression. For that, various compression methods have been proposed using different techniques to achieve high compression ratios and high image quality. One of the image compression methods is transformed based image compression using integer wavelet transform (IWT), which is the main purpose of this paper. This paper describes an algorithm of compression and decompression using (IWT). In IWT, we perform all possible decomposition of an image (i.e. until image size 2 ×2), after that the resultant coefficients are arranged according to their impotency using zigzag arrangement and divided on factor related to their impotency (increase the factor with low impotency), to make low impotency coefficient related to zero. Remap the values to the range (1.255) (i.e. byte). Then perform lossy or lossless Run Length Coding (RLC) to construct the codebook of the compressed image. The effects of different RLC and different initial quantization factor, image contents and compression ratios assessed. The results provide a good reference for application developers to choose a good wavelet compression system for their application.

DC-free multimode code design using novel selection criteria for optical recording systems

DC-free run-length limited codes have been the cornerstone of all three generations of optical recording, CD, DVD and BD. Research into very efficient coding methods is paramount for the upcoming fourth generation. Guided Scrambling (GS) is an efficient coding method that has been reported in the literature. Under GS rules, a user word is translated into a plurality of possible candidate words, and among the candidate words the encoder selects the codeword with the least low-frequency spectral content. In our paper, we will present results of our attempts to improve the performance of GS-based codes. We will present new selection criteria and evaluate their performance and complexity. Specifically, we will evaluate the new selection criteria to the 2/3(1,7) parity preserving code used in Blu-Ray Disc.

Test Compression for Robust Testable Path Delay Fault Testing Using Interleaving and Statistical Coding

This paper proposes a method providing efficient test compression. The proposed method is for robust testable path delay fault testing with scan design facilitating two-pattern testing. In the proposed method, test data are interleaved before test compression using statistical coding. This paper also presents test architecture for two-pattern testing using the proposed method. The proposed method is experimentally evaluated from several viewpoints such as compression rates, test application time and area overhead. For robust testable path delay fault testing on 11 out of 20 ISCAS89 benchmark circuits, the proposed method provides better compression rates than the existing methods such as Huffman coding, run-length coding, Golomb coding, frequency-directed run-length (FDR) coding and variable-length input Huffman coding (VIHC).

Joint Optimization of Run-Length Coding, Huffman Coding, and Quantization Table With Complete Baseline JPEG Decoder Compatibility

To maximize rate distortion performance while remaining faithful to the JPEG syntax, the joint optimization of the Huffman tables, quantization step sizes, and DCT indices of a JPEG encoder is investigated. Given Huffman tables and quantization step sizes, an efficient graph-based algorithm is first proposed to find the optimal DCT indices in the form of run-size pairs. Based on this graph-based algorithm, an iterative algorithm is then presented to jointly optimize run-length coding, Huffman coding, and quantization table selection. The proposed iterative algorithm not only results in a compressed bitstream completely compatible with existing JPEG and MPEG decoders, but is also computationally efficient. Furthermore, when tested over standard test images, it achieves the best JPEG compression results, to the extent that its own JPEG compression performance even exceeds the quoted PSNR results of some state-of-the-art wavelet-based image coders such as Shapiro's embedded zerotree wavelet algorithm at the common bit rates under comparison. Both the graph-based algorithm and the iterative algorithm can be applied to application areas such as web image acceleration, digital camera image compression, MPEG frame optimization, and transcoding, etc.

Hardware architecture for AVS entropy encoder

In A VS-P2 video compression standard, similar to MPEG-2, entropy coding firstly assembles two dimensional coefficients of each block into a sequence of (Run, Level) combinations serially. As we know, such the serial run-length method is usually undesirable for hardware accelerator and thus, this paper proposes an efficient parallel algorithm to Run-Length Coding, which can determine the (Run, Level) combinations for one row of coefficients from a block in one clock cycle. In addition, Level-based multiple VLC tables switch mechanism (Context-based VLC) is further introduced in AVS-P2 entropy coding module to identify the big variation of probability distribution of (Run, Level) combinations. As a result, table selection for coding the current Level necessarily depends on the previously coded coefficients. Thus, we propose a parallel Looking-Up Table method, which can select the tables for one row of coefficients from a block in one clock cycle. On the other hand, at RDO stage, the calculation of rate term only needs to get the number of bits for each coded signal without the knowledge of its concrete value. Consequently, in hardware design, the Looking-Up Table in pre-coding can be mapped into a series of logic operations and thus much hardware memory can be saved. At the actual entropy coding, we only need to replace the logic operation of pre-coding with the actual 2D-VLC tables. Using our proposed hardware accelerator of AVS entropy coder, the results of simulation and synthesis demonstrate that the computing complexity and memory requirements are both reduced .

Dilation-run wavelet image coding

The run-length coding and the morphological representation are two classical schemes for wavelet image coding. The run-length coders have the advantage of simplicity by recording the lengths of zero-runs between significant wavelet coefficients but at the expense of yielding an inferior rate-distortion performance. The morphology-based coders, on the other hand, utilize the morphological dilation operation to delineate the clusters of significant coefficients for improving coding performance. In this paper, a novel dilation-run image coding algorithm is developed by taking the advantages of both schemes, in which the clustered significant coefficients are extracted by using the morphological dilation operation and the insignificant coefficients between the extracted clusters are coded by using the run-length coding method. The proposed dilation-run image coder is implemented in the framework of bitplane coding for producing embedded bitstreams. Compared with several state-of-the-art wavelet image coding methods, the proposed dilation-run image coding method achieves comparable rate-distortion coding performance, especially more attractive for fingerprint type of imageries.

Optimal Parsing Trees for Run-Length Coding of Biased Data

We study coding schemes which encode unconstrained sequences into run-length-limited (d, k)-constrained sequences. We present a general framework for the construction of such (d, k)-codes from variable-length source codes. This framework is an extension of the previously suggested bit stuffing, bit flipping, and symbol sliding algorithms. We show that it gives rise to new code constructions which achieve improved performance over the three aforementioned algorithms. Therefore, we are interested in finding optimal codes under this framework, optimal in the sense of maximal achievable asymptotic rates. However, this appears to be a difficult problem. In an attempt to solve it, we are led to consider the encoding of unconstrained sequences of independent but biased (as opposed to equiprobable) bits. Here, our main result is that one can use the Tunstall source coding algorithm to generate optimal codes for a partial class of (d, k) constraints.

Binary permutation sequences as subsets of Levenshtein codes, spectral null codes, run-length limited codes and constant weight codes

We investigate binary sequences which can be obtained by concatenating the columns of (0,1)-matrices derived from permutation sequences. We then prove that these binary sequences are subsets of a surprisingly diverse ensemble of codes, namely the Levenshtein codes, capable of correcting insertion/deletion errors; spectral null codes, with spectral nulls at certain frequencies; as well as being subsets of run-length limited codes, Nyquist null codes and constant weight codes.

Test data compression for system-on-a-chip using extended frequency-directed run-length code

One of the major challenges in testing a system-on-a-chip is dealing with the large volume of test data. To reduce the volume of test data, several test data compression techniques have been proposed. Frequency-directed run-length (FDR) code is a variable-to-variable run length code based on encoding runs of 0s. It is demonstrated that higher test data compression can be achieved based on encoding both runs of 0s and 1s. An extension to the FDR code is proposed and by experimental results its effectiveness in achieving a higher compression ratio is demonstrated.

Compression rates comparison of entropy coding for three-bit chain codes of bilevel images

We carried out a comparative study between different entropy coding schemes applied to bilevel images. The study was centered on their application to reduce existing redundancies in the three-bit chain code used to compress bilevel images. We propose a variant of the run-length codes using joint runs of two symbols at the same time. According to our results, the number of bits needed to store chain codes is reduced more than 50% over the case that is not compressed, and a 45% improvement is achieved over the results obtained with classical Huffman coding.