Analysis of Optimal Search Interval for Estimation of Modified Quantization Step Size in Quantization-Based Audio Watermark Detection

2006 ◽  
pp. 241-252
Author(s):  
Siho Kim ◽  
Keunsung Bae
Keyword(s):  
Optimal Search ◽  
Step Size ◽  
Quantization Step ◽  
Audio Watermark ◽  
Search Interval

scholarly journals Eccentricity Parameters Identification for a Motorized Spindle System Based on Improved Maximum Likelihood Method

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Wengui Mao ◽  
Chaoliang Hu ◽  
Jianhua Li ◽  
Zhonghua Huang ◽  
Guiping Liu
Keyword(s):  
Maximum Likelihood ◽  
Measurement Errors ◽  
Maximum Likelihood Method ◽  
Search Algorithm ◽  
A Priori ◽  
Likelihood Method ◽  
Step Size ◽  
Spindle System ◽  
Grinding Machine ◽  
Search Interval

As a kind of rotor system, the electric spindle system is the core component of the precision grinding machine. The vibration caused by the mass imbalance is the main factor that causes the vibration of the grinding machine. Identifying the eccentricity parameters in an electric spindle system is a key issue in eliminating mass imbalances. It is difficult for engineers to understand the approximate range of eccentricity by experience; that is, it is difficult to obtain a priori information about eccentricity. At the same time, due to the geometric characteristics of the electrospindle system, the material factors and the randomness of the measurement response, these uncertain factors, even in a small case, are likely to cause large deviations in the eccentricity recognition results. The search algorithm used in the maximum likelihood method to identify the eccentricity parameters of the electrospindle system is computationally intensive, and the sensitivity in the iterative process brings some numerical problems. This paper introduces an Advance-Retreat Method (ARM) of the search interval to the maximum likelihood method, the unknown parameter increment obtained by the maximum likelihood method is used as the step size in the iteration, and the Advance-Retreat Method of the search interval is used to adjust the next design point so that the objective function value is gradually decreasing. The recognition results under the three kinds of measurement errors show that the improved maximum likelihood method improves the recognition effect of the maximum likelihood method and can reduce the influence of uncertainty factors on the recognition results, and the robustness is satisfactory.

Synchronization of Transmission Systems with ANS-DM Codecs

2021 ◽  
Vol 12 (1) ◽  
pp. 37-44
Author(s):  
Ryszard Golański ◽  
Juliusz Godek
Keyword(s):  
Signal Reconstruction ◽  
Step Size ◽  
Time Duration ◽  
Quantization Step ◽  
Uniform Sampling ◽  
Variable Time ◽  
Synchronization Method ◽  
Delta Modulation ◽  
Non Uniform Sampling ◽  
Sampling Instant

Adaptive Delta Modulation with Non-uniform Sampling (ANS-DM) is one of the waveform coding techniques, where a sampling instant and a quantization step size are adapted to the signal. The ANS-DM modulator produces an output binary stream, that carries information about the signal and includes necessary data of coder parameters (sampling instant and quantization step). In the demodulator, these values are recovered for proper signal reconstruction. The paper reports the problem of synchronizing clocks (transmitting and receiving) in the (ANS-DM) delta codecs systems. The original synchronization method, valuable in systems dedicated to the transmission of the bits with variable time duration was projected and experimentally verified. Performed measurements and observations have shown the elimination of the synchronization loss phenomenon.

An Improved H.264 Codec Algorithm Based on Regions of Interest

2011 ◽  
Vol 291-294 ◽  
pp. 2794-2798
Author(s):  
Zheng You Wang ◽  
Zhen Xing Li ◽  
Jian Hua Ming
Keyword(s):  
Region Of Interest ◽  
Regions Of Interest ◽  
Subjective Quality ◽  
Experimental Results ◽  
Bit Rate ◽  
Step Size ◽  
Quantization Step ◽  
Regional Interest ◽  
Inverse Quantization

Because observers’ attention to the region of interest is higher than other parts (the background) of the image , This paper discribes an improved H.264 codec algorithm based on regions of interest. This method according to the degree of regional interest, adjusting the quantization step size, quantified the region of interest in detailed, and coarsely quantized other regions. ROI information was transmitted to the decoder and then carried out corresponding inverse quantization. Experimental results show that the output bit rate was decreased of 10% -20% by using this improved algorithm in H.264 reference encoder, but the subjective quality of decoded image is as good as the standard H.264 encoders.

scholarly journals Transcoding Method of H.264 Coded Bitstream for Interest Region

2009 ◽  
Vol 8 (3) ◽  
pp. 45-50 ◽  
Author(s):  
Ya-lin Wu ◽  
Soon-kak Kwon
Keyword(s):  
Video Sequence ◽  
The Other ◽  
Classification Method ◽  
Picture Quality ◽  
Step Size ◽  
Quantization Step

We propose a transcoding method of H.264 coded bitsteam to control the picture quality dependently on the interest region. In the proposed method, first we find the model of quantization step-size and bitrate. Then a classification method according to the subjectively interest region within a video sequence is suggested. Also we propose a method that assigns a specific quantization step-size differentially according to the interest region within a video. In general, the subjective picture quality can be increased by applying the quantization step-size as a small value relatively for the interest region compared with the other regions. From the simulation, we show that the proposed method can make better subjective picture quality relatively in parts of interest region.

scholarly journals Quantization-Based Image Watermarking by Using a Normalization Scheme in the Wavelet Domain

Information ◽  
2018 ◽  
Vol 9 (8) ◽  
pp. 194 ◽  
Author(s):  
Jinhua Liu ◽  
Qiu Tu ◽  
Xinye Xu
Keyword(s):  
Wavelet Coefficient ◽  
Image Watermarking ◽  
Probability Of Detection ◽  
Experimental Simulation ◽  
False Alarms ◽  
Step Size ◽  
Image Region ◽  
Quantization Step ◽  
High Entropy ◽  
Watermark Embedding

To improve the invisibility and robustness of quantization-based image watermarking algorithms, we developed an improved quantization image watermarking method based on the wavelet transform and normalization strategy used in this study. In the process of watermark encoding, the sorting strategy of wavelet coefficients is used to calculate the quantization step size. Its robustness lies in the normalization-based watermark embedding and the control of its amount of modification on each wavelet coefficient by utilizing the proper quantization parameter in a high entropy image region. In watermark detection, the original unmarked image is not required, and the probability of false alarms and the probability of detection are discussed through experimental simulation. Experimental results show the effectiveness of the proposed watermarking. Furthermore, the proposed method has stronger robustness than the alternative quantization-based watermarking algorithm.

Distortion of Neural Signals by Spike Coding

2007 ◽  
Vol 19 (10) ◽  
pp. 2797-2839 ◽  
Author(s):  
David H. Goldberg ◽  
Andreas G. Andreou
Keyword(s):  
Interspike Interval ◽  
Spike Trains ◽  
Spike Count ◽  
Neural Signals ◽  
Step Size ◽  
Quantization Step ◽  
Integrate And Fire ◽  
Coding Schemes ◽  
Spike Coding ◽  
Discrete Nature

Analog neural signals must be converted into spike trains for transmission over electrically leaky axons. This spike encoding and subsequent decoding leads to distortion. We quantify this distortion by deriving approximate expressions for the mean square error between the inputs and outputs of a spiking link. We use integrate-and-fire and Poisson encoders to convert naturalistic stimuli into spike trains and spike count and inter-spike interval decoders to generate reconstructions of the stimulus. The distortion expressions enable us to compare these spike coding schemes over a large parameter space. We verify that the integrate-and-fire encoder is more effective than the Poisson encoder. The disparity between the two encoders diminishes as the stimulus coefficient of variation (CV) increases, at which point, the variability attributed to the stimulus overwhelms the variability attributed to Poisson statistics. When the stimulus CV is small, the interspike interval decoder is superior, as the distortion resulting from spike count decoding is dominated by a term that is attributed to the discrete nature of the spike count. In this regime, additive noise has a greater impact on the interspike interval decoder than the spike count decoder. When the stimulus CV is large, the average signal excursion is much larger than the quantization step size, and spike count decoding is superior.

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