An analysis of flooding coverage using remote sensing within the context of risk assessment

Abstract Results of research of the identification of flooding as a result of groundwater table fluctuations on the example of the valley of the River Vistula, with the use of multi-spectral Sentinel-2 images from the years 2017–2018 are presented. An analysis of indexes of water use, calculated on the basis of green, red and shortwave infrared (SWIR) bands, for extraction of water objects and flooded areas was carried out. Based on the analyses conducted, a mapping method was developed, using three water indexes (MNDWI Modified Normalised Difference Water Index, NDTI Normalised Difference Index and NDPI Normalised Difference Pond Index). Results show that the 10 metre false colour composite RNDTIGNDPIBMNDWI obtained significantly improved submerged extractions more than did individual water indexes. Moreover, the 10-m-images of MNDWI and NDPI, obtained by the sharpening High Pass Filter (HPF), may represent more detailed spatial information on floods than the 20-m-MNDWI and NDPI, obtained from original images.

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Echo-Imaging Exploits an Environmental High-Pass Filter to Access Spatial Information with a Non-Spatial Sensor

iScience ◽

10.1016/j.isci.2019.03.029 ◽

2019 ◽

Vol 14 ◽

pp. 335-344 ◽

Cited By ~ 2

Author(s):

A. Leonie Baier ◽

Lutz Wiegrebe ◽

Holger R. Goerlitz

Keyword(s):

Spatial Information ◽

Pass Filter ◽

High Pass Filter ◽

High Pass

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A NEW INDEX FOR IDENTIFYING WATER BODY FROM SENTINEL-2 SATELLITE REMOTE SENSING IMAGERY

ISPRS Annals of Photogrammetry Remote Sensing and Spatial Information Sciences ◽

10.5194/isprs-annals-v-3-2020-33-2020 ◽

2020 ◽

Vol V-3-2020 ◽

pp. 33-38

Author(s):

W. Jiang ◽

Y. Ni ◽

Z. Pang ◽

G. He ◽

J. Fu ◽

...

Keyword(s):

Water Body ◽

Salt Lake ◽

Spectral Characteristics ◽

River Estuary ◽

Yangtze River Estuary ◽

Infrared Band ◽

Water Index ◽

Normalized Difference Water Index ◽

Shortwave Infrared ◽

Sentinel 2

Abstract. Water body plays an irreplaceable role in the global ecosystem and climate system. Sentinel-2 is a new satellite data with higher spatial and spectral resolution. Through analysing spectral characteristics of Sentinel-2 satellite imagery, the brightness of water body in vegetation red edge band and shortwave infrared band showe sharply different than that of the not water body. Therefore, a new type of water index SWI (Sentinel-2 Water Index) was proposed by combing those two bands. Four representative water types, which included Taihu Lake, the Yangtze River Estuary, the ChaKa Salt Lake and the Chain Lake, were selected as experimental areas. Normalized difference water index (NDWI) and Sentinel-2 Water Index (SWI) with Otsu method were employed to extract water body. The results showed that overall accuracy and Kappa coefficient of SWI were higher than that of NDWI and SWI was efficient index to rapidly and accurately extract water for Sentinel-2 data. Therefore, SWI had application potential for larger scale water mapping in the future.

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Land-use Mapping by Satellite Imagery

Geografie ◽

10.37040/geografie1993098030170 ◽

1993 ◽

Vol 98 (3) ◽

pp. 170-178

Author(s):

Miroslav Koželuh

Keyword(s):

Land Use ◽

Satellite Imagery ◽

Mapping Method ◽

False Colour Composite ◽

Landsat Tm ◽

Visual Interpretation ◽

Southern Moravia ◽

Colour Composite ◽

False Colour ◽

Land Use Maps

The land-use mapping method based on the interpretation of satellite imagery is described. Out of various processes applied for obtaining the information on parcelation and thematic contents of the land-use map, the visual interpretation of multispectral false colour composite (FCC) of LANDSAT TM was used. The practical applicability of this method has been verified by the construction of land-use maps on the scales 1 : 50 000 and 1 : 200 000 on the territory of Southern Moravia.

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A V-Band Two Pole High-Pass Filter for Frequency Quadrupler Design

International Journal on Communications Antenna and Propagation (IRECAP) ◽

10.15866/irecap.v6i1.8322 ◽

2016 ◽

Vol 6 (1) ◽

pp. 56

Author(s):

Maryam Abata ◽

Mahmoud Mehdi ◽

Said Mazer ◽

Moulhime El Bekkali ◽

Catherine Algani

Keyword(s):

Pass Filter ◽

High Pass Filter ◽

V Band ◽

High Pass

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Novel Compact High-Pass Filter with Sharp Attenuation Slope Using Cross-Coupling in the Multi-Layer Structure

IEICE Transactions on Electronics ◽

10.1587/transele.e95.c.313 ◽

2012 ◽

Vol E95-C (2) ◽

pp. 313-316

Author(s):

Takenori YASUZUMI ◽

Tomoki UWANO ◽

Osamu HASHIMOTO

Keyword(s):

Layer Structure ◽

Cross Coupling ◽

Pass Filter ◽

High Pass Filter ◽

High Pass

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Baseline-free sensor fault detection for piezoelectric array

Journal of Intelligent Material Systems and Structures ◽

10.1177/1045389x211018853 ◽

2021 ◽

pp. 1045389X2110188

Author(s):

Qibo Mao ◽

Yuande Wang ◽

Shizuo Huang

Keyword(s):

Prior Knowledge ◽

Frequency Response Function ◽

Sensor Array ◽

Piezoelectric Element ◽

Piezoelectric Sensor ◽

Steel Beam ◽

Sensor Fault ◽

Pass Filter ◽

Sensor Fault Detection ◽

High Pass

In this study, a new methodology is presented to detect the sensor fault for piezoelectric array based on the filtered frequency response function (FRF) shapes. The proposed method does not require prior knowledge about healthy piezoelectric array. First, the imaginary parts of FRFs from the piezoelectric array during vibration are measured and normalized to obtain the FRF shapes in different frequencies. Then the irregularities in these FRF shapes are extracted by using high-pass filter with properly chosen cut-off frequency. These abnormal irregularities on the filtered FRF shape curves indicate the location of the faulty sensor, due to the irregularity of FRF shapes introduced by the faulty piezoelectric element. The proposed sensor fault method is experimentally demonstrated on a clamped-clamped steel beam mounted with piezoelectric buzzer array. Two common piezoelectric sensor fault types including sensor breakage and debonding are evaluated. The experimental results indicate that the proposed method has great potential in the detection of the sensor fault for piezoelectric array as it is simple and does not require the FRF data of the healthy sensor array as a baseline.

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Modeling of Durum Wheat Yield Based on Sentinel-2 Imagery

Agronomy ◽

10.3390/agronomy11081486 ◽

2021 ◽

Vol 11 (8) ◽

pp. 1486

Author(s):

Chris Cavalaris ◽

Sofia Megoudi ◽

Maria Maxouri ◽

Konstantinos Anatolitis ◽

Marios Sifakis ◽

...

Keyword(s):

Vegetation Index ◽

Normalized Difference Vegetation Index ◽

Vegetation Indices ◽

Model Development ◽

Wheat Yield ◽

Growth Period ◽

Yield Data ◽

Water Index ◽

Normalized Difference Water Index ◽

Sentinel 2

In this study, a modelling approach for the estimation/prediction of wheat yield based on Sentinel-2 data is presented. Model development was accomplished through a two-step process: firstly, the capacity of Sentinel-2 vegetation indices (VIs) to follow plant ecophysiological parameters was established through measurements in a pilot field and secondly, the results of the first step were extended/evaluated in 31 fields, during two growing periods, to increase the applicability range and robustness of the models. Modelling results were examined against yield data collected by a combine harvester equipped with a yield-monitoring system. Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI) were examined as plant signals and combined with Normalized Difference Water Index (NDWI) and/or Normalized Multiband Drought Index (NMDI) during the growth period or before sowing, as water and soil signals, respectively. The best performing model involved the EVI integral for the 20 April–31 May period as a plant signal and NMDI on 29 April and before sowing as water and soil signals, respectively (R2 = 0.629, RMSE = 538). However, model versions with a single date and maximum seasonal VIs values as a plant signal, performed almost equally well. Since the maximum seasonal VIs values occurred during the last ten days of April, these model versions are suitable for yield prediction.

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High-Bandpass Filters in Electrocardiography: Source of Error in the Interpretation of the ST Segment

ISRN Cardiology ◽

10.5402/2012/706217 ◽

2012 ◽

Vol 2012 ◽

pp. 1-10 ◽

Cited By ~ 22

Author(s):

F. Buendía-Fuentes ◽

M. A. Arnau-Vives ◽

A. Arnau-Vives ◽

Y. Jiménez-Jiménez ◽

J. Rueda-Soriano ◽

...

Keyword(s):

Real Time ◽

Fourier Transforms ◽

Pass Filter ◽

Discrete Fourier Transforms ◽

Real Time Mode ◽

Asymptomatic Patients ◽

St Segment ◽

Coronary Syndromes ◽

Clinically Significant ◽

High Pass

Introduction. Artifactual variations in the ST segment may lead to confusion with acute coronary syndromes. Objective. To evaluate how the technical characteristics of the recording mode may distort the ST segment. Material and Method. We made a series of electrocardiograms using different filter configurations in 45 asymptomatic patients. A spectral analysis of the electrocardiograms was made by discrete Fourier transforms, and an accurate recomposition of the ECG signal was obtained from the addition of successive harmonics. Digital high-pass filters of 0.05 and 0.5 Hz were used, and the resulting shapes were compared with the originals. Results. In 42 patients (93%) clinically significant alterations in ST segment level were detected. These changes were only seen in “real time mode” with high-pass filter of 0.5 Hz. Conclusions. Interpretation of the ST segment in “real time mode” should only be carried out using high-pass filters of 0.05 Hz.

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