The Graphical-User-Interface timestack processing application
Current version 2.0-28/08/2013
New version with:
- possibility to crop the timestacks
- possibility to zoom in and out on the timestacks and do manual corrections
- improved manual correction routine
Current version 1.3-25/06/2012
The difference with the previous one is that images now are enhanced using 2 different filters and the automatic detection performance is improved.
This application is distributed free of charge and is open source-open access
I have no responsibility about the results and I cannot give any guaranty that it works.
It will also be improved with time so keep in track with latest versions, which will include image enhancement for more robust performance.
If the application will be of any use to you, please don't forget to cite:
Vousdoukas, M.I., Wziatek, D. and Almeida, L.P. (2012). Coastal vulnerability assessment based on video wave run-up observations at a meso-tidal, reflective beach. Ocean Dynamics, 62, 123–137. DOI: 10.1007/s10236-011-0480-x.
The GUI MATLAB application is freely available from the following link: https://sourceforge.net/projects/guitimestack.
The program is initiated by the GUI_timestack command though the MATLAB command prompt and the main window consists of 5 panels, the options of which are described below:
The upper panel displaying the timestack, the extracted swash excursion tracks and the individual peaks expressing the extrema points of each identified sash front.
Additional plots panel
Includes a) a plot showing the beach profile, the R2, Rmax and ηtide levels, as well as the limits of the profile section considered for beach-face slope estimation; and b) a plot showing the wave run up spectra.
General options panel
Involves basic settings before the actual timestack processing steps.
Select data path’- setting the path of the input data files
‘Select file’- selecting a specific data file to process
‘Start from’- selecting the number of the initial data file to process (valid for the ‘Select data path’ option)
‘Next’, ‘Previous’- allow browsing through the data files. IMPORTANT: all extracted information are discarded.
Swash tracking panel
Gives the possibility to the user to enhance check the quality of the extracted data.
‘Set limit’- the user can reduce the ‘vertical dimensions of the active timestack area for image processing by clicking twice with the mouse. It is useful since be zooming on the image section containing the swash motions the performance of the swash extraction algorithm increases significantly.
‘Clear’- Deletes all the swash tracking results
‘Restart’- Restarts the timestack processing procedure, deleting the existing data for the specific data file
‘Manual mode’- Allows manual corrections on the extracted swash lines; after ‘Clear’ it allows completely manual identification.
Export options panel
Involves actions following the data extraction procedure related to data export.
‘Clean R_2’- deletes the estimated R2 value from the data file with the final results.
‘Flag’- Is an option to mark bad quality images and export them in a separate ‘Flagged’ directory.
‘Save & continue’- Exports the data output file to the ‘Exports’ directory and initiates the processing of the following input data file.
‘Quit’-Terminates the program.
Import data files
In order to process timestack images using the GUI MATLAB application the data have to be organized in separate MATLAB structure files named ‘stack’. Once the data path is set the program will search and open and contained .mat files so only the timestack files should be included in the data directory. The ‘stack’ structure should include the following variables:
stack- the time stack image nx x nt; where nx expresses the number of grid points along the beach transect considered for timestack generation and nt the number of individual snapshots processed to generate the timestack image.
x, z- cross-shore real world coordinates and elevation of the beach transect considered for timestack generation.
Hs- corresponding Significant wave height
Tp- corresponding Peak wave period
Dir- corresponding Wave direction
lev- corresponding tidal elevation
date- corresponding date
time- corresponding time
gen_sdate- corresponding MATLAB serial date (one value)
sdate- time series of MATLAB serial date corresponding to the acquisition time of the individual snapshots processed to generate the timestack image.
Export data files
The data output is included in a ‘exprt’ structure file with the following variables:
R- timeseries of the wave run up elevation
tsecs- timeseries of the corresponding time in seconds
R2- estimated R2 value
Rmax- estimated Rmax value
spectra.f- frequency variable of the estimated wave run up spectra
spectra.Y- spectral density variable of the estimated wave run up spectra
Rx- timeseries of the cross-shore swash excursion position
R2x- 2% exceedence value of the cross-shore swash excursion position
Rmax_x- maximum cross-shore swash excursion position
meta- timestack metadata including the basic data input variables.