Frequency Domain Estimation and Correction Algorithm of Row Displacement for Scanning PMMW Imaging

2013 ◽  
Vol 34 (2) ◽  
pp. 205-216
Author(s):  
Jian-Yu Yang ◽  
Rui-Jie Tan ◽  
Jin-Tao Xiong ◽  
Liang-Chao Li
Keyword(s):  
Frequency Domain ◽  
Correction Algorithm ◽  
Estimation And Correction

Research on Correction Algorithm for Print-Scan Resistant Digital Watermarking Algorithms Based on DWT

2012 ◽  
Vol 262 ◽  
pp. 172-176
Author(s):  
Zhen Jie Zhang ◽  
Zhen Liu ◽  
Hui Yu
Keyword(s):  
Frequency Domain ◽  
Digital Watermarking ◽  
High Amplitude ◽  
Correction Coefficient ◽  
Correction Algorithm ◽  
Before And After ◽  
Kolmogorov Smirnov ◽  
Contrast Stretching ◽  
Smirnov Test

On the basis of the analysis of the second layer of DWT high amplitude coefficients before and after printing and scanning, we propose a correction algorithm for Print-scan resistant Digital Watermarking Algorithms Based on DWT. This correction algorithm corrects in the frequency domain, multiplying the coefficients by a correction coefficient and determining the best correction coefficient by Kolmogorov-Smirnov test. Contrast with two common methods to correct the distorted pixels: brightness transformation and contrast stretching transformation, this correction algorithm has the character of less calculation and takes the influence of print and scan on the surrounding pixels into account. At last, after applying it to several test images and all the NC values becoming bigger, the proposed correction algorithm is proved to be effective and universal.

Efficient skew estimation and correction algorithm for document images

2002 ◽  
Vol 20 (1) ◽  
pp. 25-35 ◽  
Author(s):  
H.K. Kwag ◽  
S.H. Kim ◽  
S.H. Jeong ◽  
G.S. Lee
Keyword(s):  
Document Images ◽  
Correction Algorithm ◽  
Estimation And Correction

Test Frequency-Domain Parameters of ADCs Using a Spectrum Leakage Correction Algorithm

2012 ◽  
Vol 588-589 ◽  
pp. 924-927
Author(s):  
Shi Rong Yin
Keyword(s):  
Frequency Domain ◽  
Polynomial Approximation ◽  
Approximation Method ◽  
Interpolation Algorithm ◽  
Test Frequency ◽  
Correction Algorithm ◽  
Spectral Leakage ◽  
Parameters Calculation

This paper analyzed the principle of the interpolation algorithm and the cause of spectrum leakage, derived an interpolation formulas of estimation the incoherent degree to correct the spectrum. Polynomial approximation method is used to get the correction formulas. Simulate results demonstrate that the correction Algorithm can reduced the spectral leakage and increase ADC parameters calculation accuracy.

scholarly journals Estimation and Correction of Gain Mismatch and Timing Error in Time-Interleaved ADCs Based on DFT

2014 ◽  
Vol 21 (3) ◽  
pp. 535-544 ◽  
Author(s):  
Lianping Guo ◽  
Shulin Tian ◽  
Zhigang Wang
Keyword(s):  
Fourier Transform ◽  
Numerical Simulations ◽  
Discrete Fourier Transform ◽  
Analog To Digital Converter ◽  
Digital Converter ◽  
Correction Algorithm ◽  
Timing Error ◽  
Analog To Digital ◽  
Time Interleaved ◽  
Estimation And Correction

Abstract Time-interleaved analog-to-digital converter (ADC) architecture is crucial to increase the maximum sample rate. However, offset mismatch, gain mismatch, and timing error between time-interleaved channels degrade the performance of time-interleaved ADCs. This paper focuses on the gain mismatch and timing error. Techniques based on Discrete Fourier Transform (DFT) for estimating and correcting gain mismatch and timing error in an M-channel ADC are depicted. Numerical simulations are used to verify the proposed estimation and correction algorithm.

Correction to "The analysis of slug tests in the frequency domain" (WRR 25(11), pp. 2388-2396

1990 ◽  
Vol 26 (8) ◽  
pp. 1863-1863
Author(s):  
Paul Marschall ◽  
Baldur Barczewski
Keyword(s):  
Frequency Domain ◽  
Slug Tests
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