Friday, July 8, 2016

Import in Matlab temporal signals (waveforms) recorded in .hws files by a National Instruments digitizer

National Instruments digitizers can save temporal signals, i.e., waveforms, in binary files with a National Instruments' proprietary format called Hierarchical Waveform Storage, based upon the HDF5 format for data storage and representation.

A waveform stored in a file with that format contains not only the time series of the signal, rather a huge amount of other data and metadata about the measurement configuration and about the settings of the National Instruments digitizer.

These additional data and metadata can be extremely useful to recover information about scaling factors, sampling rate, instrument settings, etc. ...

A .hws is a HDF5 file, thus it can be explored and read in by Matlab using its built-in functions for reading HDF5 datasets and attributes.

See this post and this other one for a few hints about importing in Matlab a waveform stored in a .hws file.

Wednesday, December 31, 2014

Scalar or vector field on structured, uniform grid - Create VTK file for loading into Paraview

Thanks to Joe Yeh for having created a Matlab function, vtkwrite(...), to create a file where scalar and/or vector fields defined on a structured, uniform and regular grid can be saved according to the VTK format needed to be imported in Paraview.
It's a very handy function. To create scalar and vector fields defined on a structured, uniform and regular grid is easy in Matlab. To be able to load the dataset into Paraview is fantastic because one can exploit the powerful visualization and analysis tools of that software.
The Matlab function can be downloaded from this URL.

Load a 3D image in Paraview

How to import a stack of 2D images (3D image) in Paraview?
It may seem a trivial question ... but without knowing some details it may take some time the first time one tries doing that.
See some useful tips at this URL.
Thanks to the Univ. of Manchester, IT Services Group and Computational Science Community Wiki administrators for posting these tips.

Wednesday, July 30, 2014

Create a new shortcut to a command in ImageJ/Fiji

Very useful when you frequently call a command and you want to avoid wandering around/through the command menu trees.
Go to the Plugins menu. Choose Shortcuts, then the Create shortcut... command.

Thursday, June 12, 2014

Extract data from a Matlab plot

Very useful instructions about how to extract the data plotted in a figure saved as a Matlab figure (.fig format file), in order to be able to re-plot the data in a different way.