Non-Uniformity Correction Method Based on Standard Deviation Value Compensation after Moment Matching

2013 ◽  
Vol 33 (12) ◽  
pp. 1211002
Author(s):  
祝善友 Zhu Shanyou ◽  
张桂欣 Zhang Guixin ◽  
巩彩兰 Gong Cailan ◽  
祝令亚 Zhu Lingya ◽  
赫华颖 He Huaying ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Correction Method ◽  
Moment Matching

Research on Real-Time Laser Range Finding System

2013 ◽  
Vol 347-350 ◽  
pp. 1053-1058
Author(s):  
Fang Xiu Jia ◽  
Ji Yan Yu ◽  
Zhen Liang Ding ◽  
Feng Yuan
Keyword(s):  
Standard Deviation ◽  
Real Time ◽  
Amplitude Spectrum ◽  
Correction Method ◽  
Laser Range Finder ◽  
Range Finder ◽  
Measurement Standard ◽  
Laser Range ◽  
Frequency Correction ◽  
Better Than

Phase shift laser range finder, as a large-scale, high-precision measurement method, is widely used in industrial and military fields. The traditional laser range finder can not meet the need of real-time, high resolution measurement because of its low anti-jamming capability and time-consuming measurement. Owing to this, multi-channel transmitting and receiving system for phase shift laser range finder based on parallel DSP was designed. Multi-frequency modulation laser can be transmitted and received at the same time, improving the measurement speed and avoiding the wrong data fusion because of target moving. The distance was got by measuring the phase difference between the measurement signal and reference signal, and the Doppler velocity of the target is got by measuring the measurement signals frequency, The measurement signals reference signals were acquired by parallel AD convertors, the phase difference between them was calculated adopting all-phase FFT(apFFT). A new frequency correction method was proposed according to the amplitude spectrum acquired by apFFT, Amplitude spectrum is expanded into Taylor series and the correction value of frequency is calculated by relationship of spectrum lines. Monte Carlo simulation results proved that the new frequency correction method had higher resolution and better stability than Rife method and centro-baric method. The experiments is implemented on a precision guide of 3m-long, on the condition that the sampling frequency of AD converter is 937.5KHz, the apFFT transform point number is 4096, distance and velocity results can be obtained each 10ms, experiments prove that the distance measurement standard deviation better than 0.09mm and the velocity measurement standard deviation better than 0.022m/s are obtained. The system can meet the need of high accuracy ,real-time distance measurement of moving target.

scholarly journals A Practical Pyrgeometer Using the Representative Angle

2009 ◽  
Vol 26 (3) ◽  
pp. 647-655 ◽  
Author(s):  
Satoshi Sakai ◽  
Aya Ito ◽  
Kazuhiro Umetani ◽  
Isao Iizawa ◽  
Masanori Onishi
Keyword(s):  
Standard Deviation ◽  
Correlation Coefficient ◽  
Spectral Sensitivity ◽  
Zenith Angle ◽  
Street Canyon ◽  
Correction Method ◽  
Directional Response ◽  
Household Appliances ◽  
Spectral Correction ◽  
New System

Abstract A simple directional pyrgeometer is tested and compared with a conventional standard pyrgeometer. The system presented in this article has a narrow directional response and points to the representative zenith angle of 52.5°. Because of its directional response, it can be used in a street canyon or in a forest provided that a small part of the sky is visible at the representative angle. The system can be assembled using inexpensive parts that are widely used in household appliances. As this system does not have a flat spectral sensitivity, a spectral correction method is also presented. The results show that the output of the new system agrees well with that from a conventional pyrgeometer (Kipp & Zonen CG3). The correlation coefficient is 0.995 and the standard deviation is 5.6 W m−2 for 1-h averaged values.

scholarly journals NOAA-AVHRR Orbital Drift Correction: Validating Methods Using MSG-SEVIRI Data as a Benchmark Dataset

2021 ◽  
Vol 13 (5) ◽  
pp. 925
Author(s):  
Yves Julien ◽  
José A. Sobrino
Keyword(s):  
Time Series ◽  
Standard Deviation ◽  
Land Surface ◽  
Correction Method ◽  
Drift Correction ◽  
Noaa Avhrr ◽  
Coarse Spatial Resolution ◽  
Orbital Drift ◽  
Better Than

National Oceanic and Atmospheric Administration–Advanced Very High Resolution Radiometer (NOAA-AVHRR) data provides the possibility to build the longest Land Surface Temperature (LST) dataset to date, starting in 1981 up to the present. However, due to the orbital drift of the NOAA platforms, no LST dataset is available before 2000 and the arrival of newer platforms. Although numerous methods have been developed to correct this orbital drift effect on the LST, a lack of validation has prevented their application. This is the gap we bridge here by using the 15 min temporal resolution of Meteosat Second Generation–Spinning Enhanced Visible and Infra-Red Imager (MSG-SEVIRI) data to simulate drifted and reference LST time series. We then use these time series to validate an orbital drift correction method based on solar zenith angle (SZA) anomalies that we presented in a previous work (C1), as well as two variations of this approach (C0 and C2). Our results show that the C0 method performs better than the two others, although its overall bias absolute value ranges up to 1 K, while standard deviation values remain around 3 K. This is verified for most land covers, for all NOAA platforms, and these statistics remain mostly stable with noise on SZA time series (from 0° to ±10°). With this study, we show that orbital drift correction methods can be thoroughly validated and that such validation should aim toward bias absolute values below 0.1 K and standard deviation values around 1.4 K at coarse spatial resolution. To validate other orbital drift correction approaches, the drifted and reference time series used in this work are freely available for download from the first author’s webpage. This will be the first step toward the building of an orbital-drift-corrected long-term LST dataset.

scholarly journals A TWO-STEPS RADIOMETRIC CORRECTION OF SPOT-4 MULTISPECTRAL AND MULTITEMPORAL FOR SEAMLESS MOSAIC IN CENTRAL KALIMANTAN

2017 ◽  
Vol 11 (2) ◽  
pp. 97
Author(s):  
. Kustiyo ◽  
Ratih Dewanti ◽  
Inggit Lolita Sari
Keyword(s):  
Standard Deviation ◽  
Linear Function ◽  
Correction Method ◽  
Band 3 ◽  
Forest Area ◽  
Viewing Angle ◽  
Radiometric Correction ◽  
Central Kalimantan ◽  
Digital Number ◽  
Offset Coefficient

This research analyzed the radiometric correction method using SPOT-4 imageries to produce the same reflectance for the same land cover. Top of Atmosphere (TOA) method was applied in previous radiometric correction approach, this TOA approach was upgraded with the reflectance effect from difference satellite viewing angle. The 250 scene of Central Kalimantan SPOT-4 imageries from 2006 until 2012 with varies viewing angle was used. This research applied two-step approaches, the first step is TOA correction, and the second step is normalization using a linear function of reflectance and satellite viewing angle. Gain and offset coefficient of this linear function was calculated using an iterative approach to producing the same reflectance in the forest area. The target of iterative processed is to minimize the standard deviation of a digital number from a forest area in the selected region. The result shows that the standard deviation of a digital number from a forest area in the two steps approach are 8.6, 16.5, and 16.8 for band 1, band 3 and band 4. These values are smaller compared with the standard deviation of digital number result from TOA approach are 15.0, 28,3 and 34.7 for band 1, band 3 and band 4.  Decreasing the standard deviation shows the homogeneity of forest reflectance that could be seen in the seamless result. This algorithm can be applied for making seamless SPOT-4 mosaic whole of Indonesia.

Vibration Correction With Kalman Filtering Based Data Fusion for Absolute Gravimeters

2019 ◽  
Author(s):  
Yi Wen ◽  
Kang Wu ◽  
Zhenxing Li ◽  
Jiamin Yao ◽  
Meiying Guo ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Kalman Filtering ◽  
Ground Vibration ◽  
Free Fall ◽  
Vibration Signal ◽  
Correction Method ◽  
Fusion Method ◽  
Absolute Gravimeter ◽  
Single Sensor ◽  
Better Than

Abstract Free-fall absolute gravimeters are important classical high precision absolute gravimeters in many branches of scientific research. But its performance is always troubled by the ground vibration. Vibration correction method is used to correct the result by detecting the ground vibration with sensors. A Kalman filter based fusion method is proposed to obtain more accurate ground vibration signal by fusing the outputs of the seismometer and the accelerometer. Experiment is conducted with the homemade T-1 absolute gravimeter, the standard deviation of the corrected results using seismometer data and fused data are 586.32 μGal (1 μGal = 10−8 m/s2) and 508.59 μGal respectively, much better than the uncorrected result’s 6548.96 μGal. The results prove the superiority of fused data over data measured from single sensor. It is believed that the application scene of the vibration correction will be broadened and the performance of the vibration correction will also be improved by using the proposed fusion method in the future.

scholarly journals SCIAMACHY WFM-DOAS <i>X</i>CO<sub>2</sub>: reduction of scattering related errors

2012 ◽  
Vol 5 (10) ◽  
pp. 2375-2390 ◽  
Author(s):  
J. Heymann ◽  
H. Bovensmann ◽  
M. Buchwitz ◽  
J. P. Burrows ◽  
N. M. Deutscher ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Regional Scale ◽  
Correction Method ◽  
Surface Fluxes ◽  
Total Carbon ◽  
Set Covering ◽  
Retrieval Algorithm ◽  
Data Set ◽  
Data Product ◽  
Carbon Dioxide Co2

Abstract. Global observations of column-averaged dry air mole fractions of carbon dioxide (CO2), denoted by XCO2 , retrieved from SCIAMACHY on-board ENVISAT can provide important and missing global information on the distribution and magnitude of regional CO2 surface fluxes. This application has challenging precision and accuracy requirements. In a previous publication (Heymann et al., 2012), it has been shown by analysing seven years of SCIAMACHY WFM-DOAS XCO2 (WFMDv2.1) that unaccounted thin cirrus clouds can result in significant errors. In order to enhance the quality of the SCIAMACHY XCO2 data product, we have developed a new version of the retrieval algorithm (WFMDv2.2), which is described in this manuscript. It is based on an improved cloud filtering and correction method using the 1.4 μm strong water vapour absorption and 0.76 μm O2-A bands. The new algorithm has been used to generate a SCIAMACHY XCO2 data set covering the years 2003–2009. The new XCO2 data set has been validated using ground-based observations from the Total Carbon Column Observing Network (TCCON). The validation shows a significant improvement of the new product (v2.2) in comparison to the previous product (v2.1). For example, the standard deviation of the difference to TCCON at Darwin, Australia, has been reduced from 4 ppm to 2 ppm. The monthly regional-scale scatter of the data (defined as the mean intra-monthly standard deviation of all quality filtered XCO2 retrievals within a radius of 350 km around various locations) has also been reduced, typically by a factor of about 1.5. Overall, the validation of the new WFMDv2.2 XCO2 data product can be summarised by a single measurement precision of 3.8 ppm, an estimated regional-scale (radius of 500 km) precision of monthly averages of 1.6 ppm and an estimated regional-scale relative accuracy of 0.8 ppm. In addition to the comparison with the limited number of TCCON sites, we also present a comparison with NOAA's global CO2 modelling and assimilation system CarbonTracker. This comparison also shows significant improvements especially over the Southern Hemisphere.

scholarly journals SCIAMACHY WFM-DOAS XCO<sub>2</sub>: reduction of scattering related errors

2012 ◽  
Vol 5 (3) ◽  
pp. 4285-4320 ◽  
Author(s):  
J. Heymann ◽  
H. Bovensmann ◽  
M. Buchwitz ◽  
J. P. Burrows ◽  
N. M. Deutscher ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Regional Scale ◽  
Correction Method ◽  
Surface Fluxes ◽  
Total Carbon ◽  
Set Covering ◽  
Retrieval Algorithm ◽  
Data Set ◽  
Near Surface ◽  
Data Product

Abstract. Global observations of column-averaged dry air mole fractions of carbon dioxide (CO2), denoted by XCO2, retrieved from passive remote sensing instruments on Earth orbiting satellites can provide important and missing global information on the distribution and magnitude of regional CO2 surface fluxes. This application has challenging precision and accuracy requirements. SCIAMACHY on-board ENVISAT is the first satellite instrument, which measures the upwelling electromagnetic radiation in the near and short wave infrared at an adequate spectral and spatial resolution to yield near-surface sensitive XCO2. In a previous publication (Heymann et al., 2012), it has been shown by analysing seven years of SCIAMACHY WFM-DOAS XCO2 (WFMDv2.1) that unaccounted thin cirrus clouds can result in significant errors. In order to enhance the quality of the SCIAMACHY XCO2 data product, we have developed a new version of the retrieval algorithm (WFMDv2.2), which is described in this manuscript. It is based on an improved cloud filtering and correction method using the 1.4 μm strong water vapour absorption and 0.76 μm O2-A bands. The new algorithm has been used to generate a SCIAMACHY XCO2 data set covering the years 2003–2009. The new XCO2 data set has been validated using ground-based observations from the Total Carbon Column Observing Network (TCCON). The validation shows a significant improvement of the new product (v2.2) in comparison to the previous product (v2.1). For example, the standard deviation of the difference to TCCON at Darwin, Australia, has been reduced from 4 ppm to 2 ppm. The monthly regional-scale scatter of the data (defined as the mean inner monthly standard deviation of all quality filtered XCO2 retrievals within a radius of 350 km around various locations) has also been reduced, typically by a factor of about 1.5. Overall, the validation of the new WFMDv2.2 XCO2 data product can be summarised by a single measurement precision of 3.8 ppm, an estimated regional-scale (radius of 500 km) precision of monthly averages of 1.6 ppm and an estimated regional-scale relative accuracy of 0.8 ppm. In addition to the comparison with the limited number of TCCON sites, we also present a comparison with NOAA's global CO2 modelling and assimilation system CarbonTracker. This comparison also shows significant improvements especially over the Southern Hemisphere.

Nucleic Acid Molecules Prepared by Monolayer Techniques

1972 ◽  
Vol 30 ◽  
pp. 178-179
Author(s):  
Dimitrij Lang
Keyword(s):  
Electron Microscopy ◽  
Standard Deviation ◽  
Nucleic Acid ◽  
Cytochrome C ◽  
Nucleic Acids ◽  
Contour Length ◽  
Sample Standard Deviation ◽  
Molecular Weights ◽  
Length Measurements ◽  
Protein Monolayer

The success of the protein monolayer technique for electron microscopy of individual DNA molecules is based on the prevention of aggregation and orientation of the molecules during drying on specimen grids. DNA adsorbs first to a surface-denatured, insoluble cytochrome c monolayer which is then transferred to grids, without major distortion, by touching. Fig. 1 shows three basic procedures which, modified or not, permit the study of various important properties of nucleic acids, either in concert with other methods or exclusively:1) Molecular weights relative to DNA standards as well as number distributions of molecular weights can be obtained from contour length measurements with a sample standard deviation between 1 and 4%.

Reliability of the Minimum Masking Level as Outcome Variable in Tinnitus Clinical Research

2020 ◽  
Vol 29 (3) ◽  
pp. 429-435
Author(s):  
Patricia C. Mancini ◽  
Richard S. Tyler ◽  
Hyung Jin Jun ◽  
Tang-Chuan Wang ◽  
Helena Ji ◽  
...  
Keyword(s):  
Standard Deviation ◽  
High Frequency ◽  
Pearson Correlation ◽  
Correlation Coefficients ◽  
Outcome Variable ◽  
Reliable Estimate ◽  
Moderate Correlation ◽  
Trained Subjects ◽  
The Relationship ◽  
Minimum Intensity

Purpose The minimum masking level (MML) is the minimum intensity of a stimulus required to just totally mask the tinnitus. Treatments aimed at reducing the tinnitus itself should attempt to measure the magnitude of the tinnitus. The objective of this study was to evaluate the reliability of the MML. Method Sample consisted of 59 tinnitus patients who reported stable tinnitus. We obtained MML measures on two visits, separated by about 2–3 weeks. We used two noise types: speech-shaped noise and high-frequency emphasis noise. We also investigated the relationship between the MML and tinnitus loudness estimates and the Tinnitus Handicap Questionnaire (THQ). Results There were differences across the different noise types. The within-session standard deviation averaged across subjects varied between 1.3 and 1.8 dB. Across the two sessions, the Pearson correlation coefficients, range was r = .84. There was a weak relationship between the dB SL MML and loudness, and between the MML and the THQ. A moderate correlation ( r = .44) was found between the THQ and loudness estimates. Conclusions We conclude that the dB SL MML can be a reliable estimate of tinnitus magnitude, with expected standard deviations in trained subjects of about 1.5 dB. It appears that the dB SL MML and loudness estimates are not closely related.

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