scholarly journals Remote Sensing and GIS Contribution for Groundwater Mapping Reservoirs in the Baya Watershed (Eastern Region of Côte d'Ivoire)

2019 ◽  
pp. 1-14
Author(s):  
M. J. Mangoua ◽  
K. A. Kouassi ◽  
G. A. Douagui ◽  
I. Savané ◽  
J. Biémi
Keyword(s):  
Remote Sensing ◽  
Cote D'ivoire ◽  
Côte D’Ivoire ◽  
Methodological Approach ◽  
Multicriteria Analysis ◽  
Eastern Region ◽  
Cote D’Ivoire ◽  
Directional Filtering ◽  
Côte D'ivoire ◽  
Landsat 7

This study is carried out in the Baya watershed in the eastern region of Côte d'Ivoire to highlight access to drinking water issue in the fratured areas of Côte d'Ivoire. It aims at mapping the groundwater reservoirs to optimize the future installment of new boreholes for a satisfactory success rate. For the methodological approach we use Landsat 7 satellite images to map fracture networks with the use of the directional filtering technique. The induced permeabilities from these fractures were calculated using Fanciss’s method. The multicriteria analysis and Hydrogeological Information System with Spatial Reference were adopted to map groundwater reservoirs. Structural mapping by remote sensing permitted the development of detailed fractures maps with more than 6,998 listed fractures responsible for the formation of fracture aquifers in the Baya watershed. The size of these fractures is spread over two orders of magnitude. The main orientations are NE-SO (N70-80), corresponding to the Eburnean orientations, E-O (N90-100) and NO-SE (N100-120), associated with the Liberian orientation. Induced permeabilities vary from 1.20.10-8 to 4.62.10-5 m/s with a regional average of about 5.32.10-6 m/s. The zones with strong induced permeabilities that coincide with those of high fracturing densities brought us to have five reservoirs in the basin, with two large reservoirs, two media and three small ones. This groundwater flows into the mainstream waters from two main directions.

scholarly journals VOLUME BASED DTM GENERATION FROM VERY HIGH RESOLUTION PHOTOGRAMMETRIC DSMS

2016 ◽  
Vol XLI-B3 ◽  
pp. 83-90 ◽  
Author(s):  
B. Piltz ◽  
S. Bayer ◽  
A. M. Poznanska
Keyword(s):  
Ground Surface ◽  
Processing Parameters ◽  
Data Sets ◽  
Maximum Width ◽  
Directional Filtering ◽  
Very High Spatial Resolution ◽  
Efficient Scheme ◽  
Data Points ◽  
Minimum Height ◽  
Very High

In this paper we propose a new algorithm for digital terrain (DTM) model reconstruction from very high spatial resolution digital surface models (DSMs). It represents a combination of multi-directional filtering with a new metric which we call <i>normalized volume above ground</i> to create an above-ground mask containing buildings and elevated vegetation. This mask can be used to interpolate a ground-only DTM. The presented algorithm works fully automatically, requiring only the processing parameters <i>minimum height</i> and <i>maximum width</i> in metric units. Since slope and breaklines are not decisive criteria, low and smooth and even very extensive flat objects are recognized and masked. The algorithm was developed with the goal to generate the normalized DSM for automatic 3D building reconstruction and works reliably also in environments with distinct hillsides or terrace-shaped terrain where conventional methods would fail. A quantitative comparison with the ISPRS data sets <i>Potsdam</i> and <i>Vaihingen</i> show that 98-99% of all building data points are identified and can be removed, while enough ground data points (~66%) are kept to be able to reconstruct the ground surface. Additionally, we discuss the concept of <i>size dependent height thresholds</i> and present an efficient scheme for pyramidal processing of data sets reducing time complexity to linear to the number of pixels, <i>O(WH)</i>.

Comparative analysis of directional filtering techniques in fringe patterns

2011 ◽  
Author(s):  
N. Escalante ◽  
J. Villa ◽  
I. De la Rosa ◽  
E. González-Ramirez ◽  
M. Araiza
Keyword(s):  
Comparative Analysis ◽  
Directional Filtering ◽  
Fringe Patterns ◽  
Filtering Techniques

Three‐component recordings: Interest for land seismic source study

Geophysics ◽  
1987 ◽  
Vol 52 (8) ◽  
pp. 1048-1059 ◽  
Author(s):  
C. Cliet ◽  
M. Dubesset
Keyword(s):  
Principal Direction ◽  
Wave Train ◽  
Three Dimensional ◽  
Seismic Source ◽  
Real Data ◽  
Sh Wave ◽  
Directional Filtering ◽  
Local Propagation ◽  
Polarization Axis ◽  
Complex Phenomena

Three‐component recordings provide access to the particle trajectory due to seismic events. This three‐dimensional picture shows successions of complex phenomena. Nevertheless, this trajectory has predominant directions of polarization. A method of spatial directional filtering is described to calculate the polarization direction of parts of the trajectory. The application of this method provides means to reject trajectory parts for which the angular gap between their polarization axis and a reference direction, for example X, Y, or Z, is greater than a given threshold angle. Real data are submitted to this method, leading to a color‐coded display showing the direction of polarization of each wave train. The same noise spread, used in conjunction with two different seismic sources, was recorded with triphone groups. The two sources were an SH‐wave vibrator and Marthor®. Using spatial directional filterings with threshold angles varying from 0 to 90 degrees, the corresponding quantities of energy emitted in each principal direction X, Y, and Z were evaluated. A set of diagrams was plotted for comparing the behavior of both sources and to calculate the part of the received energies along X, Y, and Z directions as a function of (1) the emitted energies, and (2) the local propagation effects. ® SH‐wave weight‐drop source, IFP trademark.

Effect of Different Signal-Processing Options on Speech-in-Noise Recognition for Cochlear Implant Recipients with the Cochlear CP810 Speech Processor

2014 ◽  
Vol 25 (04) ◽  
pp. 367-379 ◽  
Author(s):  
Lisa G. Potts ◽  
Kelly A. Kolb
Keyword(s):  
Cochlear Implant ◽  
Speech Processing ◽  
Repeated Measures ◽  
Noise Cancellation ◽  
Space Environment ◽  
Speech Processor ◽  
Speech In Noise ◽  
Directional Filtering ◽  
Significant Difference ◽  
Db Difference

Background: Difficulty understanding speech in the presence of background noise is a common report among cochlear implant (CI) recipients. Several speech-processing options designed to improve speech recognition, especially in noise, are currently available in the Cochlear Nucleus CP810 speech processor. These include adaptive dynamic range optimization (ADRO), autosensitivity control (ASC), Beam, and Zoom. Purpose: The purpose of this study was to evaluate CI recipients’ speech-in-noise recognition to determine which currently available processing option or options resulted in best performance in a simulated restaurant environment. Research Design: Experimental study with one study group. The independent variable was speech-processing option, and the dependent variable was the reception threshold for sentences score. Study Sample: Thirty-two adult CI recipients. Intervention: Eight processing options were tested: Beam, Beam + ASC, Beam + ADRO, Beam + ASC + ADRO, Zoom, Zoom + ASC, Zoom + ADRO, and Zoom + ASC + ADRO. Data Collection and Analysis: Participants repeated Hearing in Noise Test sentences presented at a 0° azimuth, with R-Space restaurant noise presented from a 360° eight-loudspeaker array at 70 dB sound pressure level. A one-way repeated-measures analysis of variance was used to analyze differences in Beam options, Zoom options, and Beam versus Zoom options. Results: Among the Beam options, Beam + ADRO was significantly poorer than Beam only, Beam + ASC, and Beam + ASC + ADRO. A 1.6-dB difference was observed between the best (Beam only) and poorest (Beam + ADRO) options. Among the Zoom options, Zoom only and Zoom + ADRO were significantly poorer than Zoom + ASC. A 2.2-dB difference was observed between the best (Zoom + ASC) and poorest (Zoom only) options. The comparison between Beam and Zoom options showed one significant difference, with Zoom only significantly poorer than Beam only. No significant difference was found between the other Beam and Zoom options (Beam + ASC vs Zoom + ASC, Beam + ADRO vs Zoom + ADRO, and Beam + ASC + ADRO vs Zoom + ASC + ADRO). The best processing option varied across subjects, with an almost equal number of participants performing best with a Beam option (n = 15) compared with a Zoom option (n = 17). There were no significant demographic or audiological moderating variables for any option. Conclusions: The results showed no significant differences between adaptive directionality (Beam) and fixed directionality (Zoom) when ASC was active in the R-Space environment. This finding suggests that noise-reduction processing is extremely valuable in loud semidiffuse environments in which the effectiveness of directional filtering might be diminished. However, there was no significant difference between the Beam-only and Beam + ASC options, which is most likely related to the additional noise cancellation performed by the Beam option (i.e., two-stage directional filtering and noise cancellation). In addition, the processing options with ADRO resulted in the poorest performances. This could be related to how the CI recipients were programmed or the loud noise level used in this study. The best processing option varied across subjects, but the majority performed best with directional filtering (Beam or Zoom) in combination with ASC. Therefore in a loud semidiffuse environment, the use of either Beam + ASC or Zoom + ASC is recommended.

scholarly journals Time-directional filtering of wrapped phase for observing transient phenomena with parallel phase-shifting interferometry

2018 ◽  
Vol 26 (11) ◽  
pp. 13705 ◽  
Author(s):  
Kohei Yatabe ◽  
Risako Tanigawa ◽  
Kenji Ishikawa ◽  
Yasuhiro Oikawa
Keyword(s):  
Phase Shifting ◽  
Transient Phenomena ◽  
Phase Shifting Interferometry ◽  
Directional Filtering
Sign in / Sign up

Export Citation Format

Share Document