scholarly journals Capture-to-display delay measurement for visual communication applications

2015 ◽  
Vol 4 ◽  
Author(s):  
Haoming Chen ◽  
Chao Wei ◽  
Mingli Song ◽  
Ming-Ting Sun ◽  
Kevin Lau
Keyword(s):  
Measurement Error ◽  
Exposure Time ◽  
Visual Communication ◽  
Delay Measurement ◽  
Video Chat

We propose a method to measure the capture-to-display delay (CDD) of a visual communication application. The method does not require modifications to the existing system, nor require the encoder and decoder clocks be synchronized. Furthermore, we propose a solution to solve the multiple-overlapped-timestamp problem due to the exposure time of the camera. We analyze the measurement error, and implement the method in software to measure the CDD of a cellphone video chat application over various types of networks. Experiments confirm the effectiveness of our proposed method.

A Novel Method for High Frequency-Resolution Group Delay Acquisition Based on Tikhonov Regularization

Frequenz ◽  
2019 ◽  
Vol 73 (7-8) ◽  
pp. 281-285
Author(s):  
Rui Luo ◽  
Tianyu Pen ◽  
Shu-Na Wang ◽  
Lingyun Li
Keyword(s):  
Measurement Error ◽  
Tikhonov Regularization ◽  
High Frequency ◽  
Group Delay ◽  
Phase Measurement ◽  
Differential Method ◽  
Frequency Resolution ◽  
Delay Measurement ◽  
Novel Method ◽  
The Difference

Abstract The differential method is extensively adopted in the group delay measurement, where a contradiction between frequency-resolution and precision is present owning to the phase measurement error. This paper proposes a novel method for group delay calculating based on improved Tikhonov regularization that can omit the difference procedure. The comparative analysis demonstrates that the new method is capable of obtaining more precise group delay value along with high frequency-resolution when the measurement error of phase is included.

scholarly journals The effect of process design on refiner pulp quality control performance

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Johan Sund ◽  
Christer Sandberg ◽  
Anders Karlström ◽  
Göran Thungström ◽  
Per Engstrand
Keyword(s):  
Quality Control ◽  
Measurement Error ◽  
Residence Time ◽  
Process Model ◽  
Absolute Error ◽  
Sampling Interval ◽  
Optimization Approach ◽  
Control Performance ◽  
Error Magnitude ◽  
Delay Measurement

Abstract In this study, the effect of process- and online analyser configuration on pulp quality control is explored. The following parameters were included: analyser sampling interval, time delay, measurement error magnitude, and latency chest residence time. Using different values of parameters in a process model, a range of configurations were constructed. For each configuration, the achievable control performance was evaluated using an optimization approach. PI controller settings were chosen based on minimization of the integrated absolute error (IAE) in pulp quality after an input step disturbance. The results show that reducing the sampling interval improves performance also when the interval is smaller than the chest residence time or the analyser delay. Moreover, reducing the chest residence time can reduce the IAE by up to 40 %. However, reducing the residence time to lower than 1/3 of the sampling interval does not improve performance. Further improvement is possible if the analyser delay is reduced. The compromise between reducing the IAE and avoiding creating variation by acting on measurement error has a strong influence on the results. In conclusion, pulp quality control performance can be improved significantly by making changes to the studied configuration parameters.

Progress In The Practical Application Of Automated Image Analysis To Tem Negatives

1977 ◽  
Vol 35 ◽  
pp. 214-217
Author(s):  
F. A. Heckman ◽  
E. Redman ◽  
J.E. Connolly
Keyword(s):  
Image Analysis ◽  
Image Quality ◽  
Exposure Time ◽  
Image Contrast ◽  
Automated Image Analysis ◽  
Practical Application ◽  
Factors Affecting ◽  
High Image Quality ◽  
Qualitative Evidence ◽  
Comprehensive Study

In our initial publication on this subject1) we reported results demonstrating that contrast is the most important factor in producing the high image quality required for reliable image analysis. We also listed the factors which enhance contrast in order of the experimentally determined magnitude of their effect. The two most powerful factors affecting image contrast attainable with sheet film are beam intensity and KV. At that time we had only qualitative evidence for the ranking of enhancing factors. Later we carried out the densitometric measurements which led to the results outlined below.Meaningful evaluations of the cause-effect relationships among the considerable number of variables in preparing EM negatives depend on doing things in a systematic way, varying only one parameter at a time. Unless otherwise noted, we adhered to the following procedure evolved during our comprehensive study:Philips EM-300; 30μ objective aperature; magnification 7000- 12000X, exposure time 1 second, anti-contamination device operating.

Structure images of Si, Ge and Mos2 crystals and some application to radiation damage studies

1978 ◽  
Vol 36 (1) ◽  
pp. 292-293 ◽  
Author(s):  
K. Izui ◽  
T. Nishida ◽  
S. Furuno ◽  
H. Otsu ◽  
S. Kuwabara
Keyword(s):  
Radiation Damage ◽  
Exposure Time ◽  
Gaussian Distribution ◽  
Intensity Distribution ◽  
Chromatic Aberration ◽  
Magnetic Lens

Recently we have observed the structure images of silicon in the (110), (111) and (100) projection respectively, and then examined the optimum defocus and thickness ranges for the formation of such images on the basis of calculations of image contrasts using the n-slice theory. The present paper reports the effects of a chromatic aberration and a slight misorientation on the images, and also presents some applications of structure images of Si, Ge and MoS2 to the radiation damage studies.(1) Effect of a chromatic aberration and slight misorientation: There is an inevitable fluctuation in the amount of defocus due to a chromatic aberration originating from the fluctuations both in the energies of electrons and in the magnetic lens current. The actual image is a results of superposition of those fluctuated images during the exposure time. Assuming the Gaussian distribution for defocus, Δf around the optimum defocus value Δf0, the intensity distribution, I(x,y) in the image formed by this fluctuation is given by

Benefits from Computerized Adaptive Testing as Seen in Simulation Studies

1999 ◽  
Vol 15 (2) ◽  
pp. 91-98 ◽  
Author(s):  
Lutz F. Hornke
Keyword(s):  
Measurement Error ◽  
Computerized Adaptive Testing ◽  
Test Procedure ◽  
Adaptive Testing ◽  
Parameter Estimates ◽  
Simulation Studies ◽  
Computerized Adaptive Test ◽  
Item Banks ◽  
Item Parameters ◽  
General Reliability

Summary: Item parameters for several hundreds of items were estimated based on empirical data from several thousands of subjects. The logistic one-parameter (1PL) and two-parameter (2PL) model estimates were evaluated. However, model fit showed that only a subset of items complied sufficiently, so that the remaining ones were assembled in well-fitting item banks. In several simulation studies 5000 simulated responses were generated in accordance with a computerized adaptive test procedure along with person parameters. A general reliability of .80 or a standard error of measurement of .44 was used as a stopping rule to end CAT testing. We also recorded how often each item was used by all simulees. Person-parameter estimates based on CAT correlated higher than .90 with true values simulated. For all 1PL fitting item banks most simulees used more than 20 items but less than 30 items to reach the pre-set level of measurement error. However, testing based on item banks that complied to the 2PL revealed that, on average, only 10 items were sufficient to end testing at the same measurement error level. Both clearly demonstrate the precision and economy of computerized adaptive testing. Empirical evaluations from everyday uses will show whether these trends will hold up in practice. If so, CAT will become possible and reasonable with some 150 well-calibrated 2PL items.

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