Increase In Compression Rate Research Articles

Low‐complexity patch projection method for efficient and lightweight point‐cloud compression

AbstractThe point cloud provides viewers with intuitive geometric understanding but requires a huge amount of data. Moving Picture Experts Group (MPEG) has developed video‐based point‐cloud compression in the range of 300–700. As the compression rate increases, the complexity increases to the extent that it takes 101.36 s to compress one frame in an experimental environment using a personal computer. To realize real‐time point‐cloud compression processing, the direct patch projection (DPP) method proposed herein simplifies the complex patch segmentation process by classifying and projecting points according to their geometric positions. The DPP method decreases the complexity of the patch segmentation from 25.75 s to 0.10 s per frame, and the entire process becomes 8.76 times faster than the conventional one. Consequently, this proposed DPP method yields similar peak signal‐to‐noise ratio (PSNR) outcomes to those of the conventional method at reduced times (4.7–5.5 times) at the cost of bitrate overhead. The objective and subjective results show that the proposed DPP method can be considered when low‐complexity requirements are required in lightweight device environments.

The Characteristics of the Deformation of a Feeding Roller with Double V-Wings Honeycomb under Driven Modes with Different Rotation Rates and Axial Compressions

In this work, the roller-shaped double V-wing honeycomb (DVWH) structure was used as the object, which was designed for forest harvesting machines. The deformation characteristics of its rotation under a specific compression were studied during the feeding process for the steel feeding roller used in the traditional combined harvesting machine for trees, which is prone to damaging the wood. The compression rate (10%–15%) and rotational speed (100 mm/s–320 mm/s) were used to analyze the relationship between compression rate, rotational speed, and deformation characteristics. The deformation characteristics, characterized by equivalent stress, radial displacement sensitivity, and energy absorption efficiency, were analyzed. The results show that the deformation characteristics of the roller-shaped DVWH structure under driven mode were more sensitive to compression rate and less sensitive to changes in rotational speed. There was a positive correlation between the equivalent stress of the node and the compression rate. The peak equivalent stress of the outermost node at 10% and 15% compression rates were 111.9 MPa and 230.9 MPa. There was a negative correlation between radial displacement–compression sensitivity and compression rate, and a decrease in radial displacement–compression sensitivity from 10% to 15% compression rate at different nodes ranges from 5% to 22%. The feed performance efficiency (EF) grew from 8.3% to 12.7% for a 1% increase in compression rate.

Gaze-contingent efficient hologram compression for foveated near-eye holographic displays

Deep learning-based computer-generated holography (CGH) has developed rapidly and yielded remarkable outcomes. However, CGH rendering technologies are confronted with a significant challenge in transmitting massive holograms, which hinders the development of lightweight wearable near-eye holographic displays. Currently, hologram compression frameworks share a resemblance with image compression methods, which fail take into account the human visual system in practical near-eye displays, limiting the improvement of compression efficiency. Herein, we presented an efficient holographic compression framework based on foveated rendering, where we transmitted a high-resolution foveal region at a low compression rate and a low-resolution peripheral region at a high compression rate with dramatically reduced pixel numbers. Our method achieved a compression rate of 40× for a hologram resolution of 1024 × 1024, which represents a twofold increase in compression rate compared to the state-of-the-art (SOTA) method with a PSNR of ∼28.8 dB in the foveal image. Moreover, we further demonstrated the effectiveness of the proposed method in the optical experiment. We believe the proposed approach could be a viable remedy for the evergrowing data issue in near-eye holographic displays.

CLNet: Complex Input Lightweight Neural Network Designed for Massive MIMO CSI Feedback

The Massive Multiple Input Multiple Output (MIMO) system is a core technology of the next generation communication. With the growing complexity of CSI, CSI feedback in massive MIMO system has become a bottleneck problem, the traditional compressive sensing based CSI feedback approaches have limited performance. Recently, numerous deep learning based CSI feedback approaches demonstrate their efficiency and potential. However, most existing methods improve accuracy at the cost of computational complexity and the accuracy decreases significantly as the CSI compression rate increases. This paper presents a novel neural network CLNet tailored for CSI feedback problem based on the intrinsic properties of CSI. The experiment result shows that CLNet outperforms the state-of-the-art method by average accuracy improvement of 5.41% in both outdoor and indoor scenarios with average 24.1% less computational overhead. Codes are available at GitHub.

Implementation of VLSI Based Efficient Lossless EEG Compression Architecture using Verilog HDL

If In reality, electroencephalography signal data transfer through the Wireless Network is a frequently used device related to stability and performance problems. This study, the lossless EEG compression circuit architecture of an efficient VLSI device is suggested to increase both the capability of EEG signal transmission and reliability over WBAN. A new lossless data compression technique consisting of even a proposed neural prediction, a casting a vote solution and a quadra probability compression codec has been applied to the proposed architecture. The mid equilibrium encoder consists of a static coding table of multiple Binary and Areas such as training encoders using the comparator and multiplexer’s fundamental components. Help boost the efficiency of the proposed system; a pipelining method was applied. Produce the suggested specification, a 0.18 m CMOS technology containing 8215 gates under 100 MHz clock speed under an operating environment. To test the usefulness of the suggested compression rate technique, for 25 channels, this results in a mean value of 2.35. This work accomplished a 9.6 %increase in compression rate and a 24.1 % decrease in processing costs relative to new competition equipment lossless EEG compressed designs, although keeping a constant interface simplicity.

Fast CU Partition Decision Method Based on Bayes and Improved De-Blocking Filter for H.266/VVC

The H.266/Versatile Video Coding (VVC) standard is the latest video coding standards released by the Joint Video Exploration Group (JVET). These new technologies have brought more than 40% increase in compression rate and brought huge coding complexity. In order to reduce the coding complexity of VVC, we propose a fast Coding Unit (CU) partition decision algorithm combining Bayes algorithm and Improved De-blocking Filter (IDBF). The algorithm includes two stages. In the parameter update stage, the original VVC Test Model (VTM) is used to encode every certain video frame, and the Rough Mode Decision evaluation cost (JRMD) generated during the encoding process is used to update the parameters of the Bayes algorithm. In the fast coding stage, the video frame between two parameter update frames is encoded. First, the JRMD of the current CU is calculated and compares it with the split threshold to decide whether the current CU continues to split. If the current CU continues to be split, the current CU is divided into the same 16 simulation blocks, and the IDBF is used to calculate the texture direction and texture complexity of each simulation block. According to the texture features contained in the simulation block, the texture distribution position and texture complexity in the current CU can be judged, so that some bad candidate splitting modes can be discarded. Experimental results show that the proposed method can reduce the complexity of VVC about 56.08%, while Bjontegaard delta bit rate (BDBR) only increases by 1.30%.

Verbal Motivation vs. Digital Real-Time Feedback during Cardiopulmonary Resuscitation: Comparing Bystander CPR Quality in a Randomized and Controlled Manikin Study of Simulated Cardiac Arrest

Objective The use of smartphone applications increases bystander CPR quality as well as the use of telephone CPR protocols. The present prospective, randomized, controlled manikin trial analyses the effects of a smartphone application (PocketCPR©) on CPR quality in a bystander CPR scenario compared to a dispatcher-assisted telephone CPR with the additional use of a metronome and verbal motivation. Methods: 150 laypersons were included to perform 8-minute CPR on a manikin. Volunteers were randomly assigned to one of three groups: (1) dispatcher-assisted telephone CPR (telephone-group), (2) dispatcher-assisted telephone CPR combined with the smartphone-application (telephone + app-group) and (3) dispatcher-assisted telephone CPR with additional verbal motivation (“push harder, release completely,” every 20 seconds, starting after 60 seconds) and a metronome with 100 min−1 (telephone + motivation-group). Results: Median compression depth did not differ significantly between the study groups (p = 0.051). However, in the post hoc analysis median compression depth in the telephone + motivation-group was significantly elevated compared to the telephone + app-group (59 mm [IQR 47–67 mm] vs. 51 mm [IQR 46–57 mm]; p = 0.025). The median number of superficial compressions was significantly reduced in the telephone + motivation-group compared to the telephone + app-group (70 [IQR 3–362] vs. 349 [IQR 88–538]; p = 0.004), but not compared to the telephone-group (91 [IQR 4–449]; p = 0.707). In contrast to the other study groups, median compression depth of the telephone + motivation-group increased over time. Chest compressions with correct depth were found significantly more often in the telephone + app-group compared to the other study groups (p = 0.011). Median compression rate in the telephone + app-group was significantly elevated (108 min−1 [IQR 96–119 min−1]) compared to the telephone-group (78 min−1 [IQR 56–106 min−1]; p < 0.001) and the telephone + motivation-group (99 min−1 [IQR 91–101 min−1]; p < 0.001). Conclusions: The use of a smartphone application as well as verbal motivation by a dispatcher during telephone CPR leads to higher CPR quality levels compared to standard telephone CPR. Thereby, the use of the smartphone application mainly shows an increase in compression rate, while increased compression rate with simultaneously increased compression depth was only apparent in the telephone + motivation-group.

Experimental Study on Compression Deformation and Permeability Characteristics of Grading Broken Gangue under Stress

As the important raw material for backfill mining, broken gangue’s deformation and permeability characteristics directly affect the deformation of the overlying strata above the filling space. In this paper, through lateral compression and pressed seepage tests, the deformation and permeability characteristics of broken gangue as a function of the stress level and grading features were studied. This research indicates that the stress of broken gangue increases exponentially with an increase in strain, and the compression modulus and compression rate present a positive correlation. The samples with discontinuous grading are more difficult to compress than the continuous grading samples, and the discontinuous grading samples are tighter in accordance with the increase in compression rate. At the same time, the change range of the seepage velocity and permeability of the broken gangue decreases. Positive correction between the grading index of the broken gangue and the effect of reducing the permeability of samples is more obvious under axial compression, and less axial stress is needed to achieve the same permeability level for discontinuous grading. This paper can provide an important test basis for the design of grading parameters and the prediction of filling effects of broken gangue on backfill mining.

VLSI Implementation of an Efficient Lossless EEG Compression Design for Wireless Body Area Network

Data transmission of electroencephalography (EEG) signals over Wireless Body Area Network (WBAN) is currently a widely used system that comes together with challenges in terms of efficiency and effectivity. In this study, an effective Very-Large-Scale Integration (VLSI) circuit design of lossless EEG compression circuit is proposed to increase both efficiency and effectivity of EEG signal transmission over WBAN. The proposed design was realized based on a novel lossless compression algorithm which consists of an adaptive fuzzy predictor, a voting-based scheme and a tri-stage entropy encoder. The tri-stage entropy encoder is composed of a two-stage Huffman and Golomb-Rice encoders with static coding table using basic comparator and multiplexer components. A pipelining technique was incorporated to enhance the performance of the proposed design. The proposed design was fabricated using a 0.18 μm CMOS technology containing 8405 gates with 2.58 mW simulated power consumption under an operating condition of 100 MHz clock speed. The CHB-MIT Scalp EEG Database was used to test the performance of the proposed technique in terms of compression rate which yielded an average value of 2.35 for 23 channels. Compared with previously proposed hardware-oriented lossless EEG compression designs, this work provided a 14.6% increase in compression rate with a 37.3% reduction in hardware cost while maintaining a low system complexity.

Progression of Compression and Related Factors in Conservative Management of Osteoporotic Vertebral Compression Fractures

Purpose: The purpose of this study is to determine the ideal period of brace application for thoracolumbar (T10-L2) osteoporotic vertebral compression fracture (OVCF) based on the progression of the vertebral compression with passage of time and to evaluate the factors associated with progression of thoracolumbar OVCF, when treated conservatively. Materials and Methods: This retrospective study included a total of 46 patients who were diagnosed with thoracolumbar OVCF and could be followed-up for at least 6 months. In this study, the increase of compression rate and the mean slope of compression rate per weeks were compared between two periods (from diagnosed date to 8 weeks and from 8 weeks to 6 months), as the standard point. Age, bone mineral density (BMD), osteoporosis treatment after injury, diabetes mellitus (DM) as underlying disease were also compared between two groups (setting up 15% as standard point of increase of compression rate, ＜15% and ≥15%). Statistical analyses were performed using the paired t-test to assess the increase of compression rate and using the linear mixed model to assess the mean slope change. The relationships between the factors and progression of compression were analyzed using t-test, chi-square test, and logistic regression analysis. Results: The increase of compression rate was 13.03% and 1.97% in each period and the difference between those two periods was 11.06% (p=0.00). At 8 weeks of follow-up, the mean slope was reduced by 1.12 (p=0.00). No statistically significant difference in related factors was observed between two groups. Conclusion: Considering the increase of compression rate with passage of time, brace should be applied strictly for an initial 8 weeks. And age, BMD, osteoporosis treatment after injury, and DM as underlying disease are not predictors of progression of compression in vertebral fractures.

Hexagonal ice transforms at high pressures and compression rates directly into “doubly metastable” ice phases

We report compression and decompression experiments of hexagonal ice in a piston cylinder setup in the temperature range of 170-220 K up to pressures of 1.6 GPa. The main focus is on establishing the effect that an increase in compression rate up to 4000 MPa/min has on the phase changes incurred at high pressures. While at low compression rates, a phase change to stable ice II takes place (in agreement with earlier comprehensive studies), we find that at higher compression rates, increasing fractions and even pure ice III forms from hexagonal ice. We show that the critical compression rate, above which mainly the metastable ice III polymorph is produced, decreases by a factor of 30 when decreasing the temperature from 220 to 170 K. At the highest rate capable with our equipment, we even find formation of an ice V fraction in the mixture, which is metastable with respect to ice II and also metastable with respect to ice III. This indicates that at increasing compression rates, progressively more metastable phases of ice grow from hexagonal ice. Since ices II, III, and V differ very much in, e.g., strength and rheological properties, we have prepared solids of very different mechanical properties just by variation in compression rate. In addition, these metastable phases have stability regions in the phase diagrams only at much higher pressures and temperatures. Therefore, we anticipate that the method of isothermal compression at low temperatures and high compression rates is a tool for the academic and industrial polymorph search with great potential.

Dynamic pressure-induced dendritic and shock crystal growth of ice VI

Crystal growth mechanisms are crucial to understanding the complexity of crystal morphologies in nature and advanced technological materials, such as the faceting and dendrites found in snowflakes and the microstructure and associated strength properties of structural and icy planetary materials. In this article, we present observations of pressure-induced ice VI crystal growth, which have been predicted theoretically, but had never been observed experimentally to our knowledge. Under modulated pressure conditions in a dynamic-diamond anvil cell, rough single ice VI crystal initially grows into well defined octahedral crystal facets. However, as the compression rate increases, the crystal surface dramatically changes from rough to facet, and from convex to concave because of a surface instability, and thereby the growth rate suddenly increases by an order of magnitude. Depending on the compression rate, this discontinuous jump in crystal growth rate or "shock crystal growth" eventually produces 2D carpet-type fractal morphology, and moreover dendrites form under sinusoidal compression, whose crystal morphologies are remarkably similar to those predicted in theoretical simulations under a temperature gradient field. The observed strong dependence of the growth mechanism on compression rate, therefore, suggests a different approach to developing a comprehensive understanding of crystal growth dynamics.

Pupil plane optimization for single-mode multi-axial optical interferometry with a large number of telescopes

Future and planned optical long-baseline interferometers will allow rapid spectro-imaging at high angular resolution. A non-homothetic Fizeau instrument using optical fibres is one of the most promising concepts because it combines good sensitivity and high spectral resolution capabilities. However, when increasing the number of input telescopes, one critical issue is the design of the beam recombination scheme, at the heart of the instrument. Extending our previous analysis on the multi-axial ‘all-in-one’ recombination, where the beams are mixed all together, in this paper we tackle the possibility of reducing the number of pixels that are coding the fringes by compressing the pupil plane from a partially redundant output pupils configuration. Shrinking the number of pixels, which drastically increases with the number of recombined telescopes, is indeed a key issue that enables one to reach a higher limiting magnitude, but also allows one to lower the required spectral resolution and fasten the fringe reading process. By means of numerical simulations, we study the performances of existing estimators of the squared visibility with respect to the compression process. We show that not only does the model-based estimator lead to better signal-to-noise ratio (S/N) performances than the Fourier ones, but above all it is the only one that prevents the introduction of baseline mixing biases in the visibilities as the pupil plane compression rate increases. Furthermore, we show that moderate compression allows one to keep the S/N of the visibilities unaffected. In light of these conclusions, we propose an optimized pupil arrangement for six- and eight-beam recombiners.

Content-based scalable H.263 video coding for road traffic monitoring

For sending video data through very low bit-rate mobile channels, video codec with high compression rate is the pre-requisite. Although the H.263 video codec is recommended as one of the candidates due to its simplicity and efficiency, it is generally believed that its compression efficiency can be further improved if the content-based scalable video coding technique can be applied. In this paper, we propose a modified H.263 encoder which supports real-time content-based scalable video coding. The proposed technique is applied to real-time video surveillance systems for road traffic monitoring. For the proposed approach, the moving objects, i.e. cars, are first extracted from the steady background. Their activities are then further classified as fast or slow by assessing the regularity of their motion. The information is then passed to a modified H.263 encoder to reduce the temporal and spatial redundancies in the video. As compared with the conventional H.263 encoder using for the same application, the proposed system has a 20% increase in compression rate with negligible visual distortion. The proposed system fully complies with the ITU H.263 standard hence the encoded bit stream is completely comprehensible to the conventional H.263 decoder.

Wavelet compression and segmentation of digital mammograms.

An initial evaluation of Haar wavelets is presented in this study for the compression of mammographic images. Fifteen mammograms with 105 microns/pixel resolution and varying dynamic range (10 and 12 bits per pixel) containing clustered microcalcifications were compressed with two different rates. The quality and content of the compressed reconstructed images was evaluated by an expert mammographer. The visualization of the cluster was on the average good but degraded with increasing compression because of the discontinuities introduced by these types of wavelets as the compression rate increases. However, the artifacts in the decoded images were seen as totally artificial and were not misinterpreted by the radiologist as calcifications. The classification of the parenchymal densities did not change significantly but the morphology of the calcifications was increasingly distorted as the compression rate increased leading to lower estimates of the suspiciousness of the cluster and higher uncertainties in the diagnosis. The uncompressed and two sets of compressed images were also processed by a wavelet method to extract the calcifications. Despite the fact that the segmentation algorithm generated several false-positive signals in highly compressed images, all true clusters were successfully segmented indicating that the compression process preserved the features of interest. Our preliminary results indicated that wavelets could be used to achieve high compression rates of mammographic images without losing small details such as microcalcification clusters as well as detect the calcifications from either the uncompressed or compressed reconstructed data. Further research and application of multiresolution analysis to digital mammography is continuing.

Computer aided characterization and optimization of the Thumper compression waveform in closed-chest CPR

Optimization of blood flow and blood pressure is critical for a positive outcome of cardiopulmonary resuscitation (CPR). The use of models can facilitate the analysis of different methods of performing CPR. Programming with SPICE software, the authors modified a hardware model electrically equivalent to the human cardiovascular system into a software model to analyze and predict the hemodynamic output parameters of different compression waveform inputs used in thoracic pump CPR. Thumper waveforms produced with the computer model predicted the same decaying frequency response as those found in other studies with humans and a recording manikin in which the generated pressures decreased with increased compression rates from 60 to 140 cycles/min. Using a square-wave input having a flat frequency response, the model predicted a constant diastolic pressure and a steady increase in systolic pressure from 94 to 109 mmHg while increasing compression rate from 60 to 140 cycles/min at a constant 50% duty cycle. Blood flows predicted with the use of a square-wave compression input were greater than the flows predicted with the use of a Thumper waveform, and increased with an increase in compression rate. The model also predicted increased mean systolic pressure when the duty cycle increased from 20% to 80% while diastolic pressure decreased slightly. Although mean systolic pressure increased with increased duty cycle, the model predicted a decrease in coronary flow at the higher duty cycles of all compression waveforms. Increases of 75% to 100% in systolic pressure and blood flow were produced when increases in chest compression force and the rapidity of the rise time, termed spike-impulse CPR, were simulated.