Introduction:

This programme, based on MATLAB graphic user interfaces, has been developed to analyse image series and movies in any standard format. The interface 'uvmat' allows to scan images and velocity fields, while the 'civ' interface allows to run the free software CIVx for Correlation Imaging Velocimetry, a form of Particle Imaging Velocimetry (PIV). This software provides the following advantages:

• High level processing capabilities for PIV, with full control of the error fixing and smoothing procedures.
• Powerfull and user friendly graphic and programming capabilities of MATLAB, providing results and figures in a final form for publication.
• Systematic use of standard file formats, so that the image acquisition system is decoupled from the processing. The resulting velocity fields in netcdf format can be readily read from any computer and programme. This is important for intercomparison with theory or numerical computations. The programme itself works equally on Windows and Linux systems.
• Access to advanced processing, like three-dimensional PIV in a volume and distributed computation as a background task in a computer cluster.
• The software is fully open. It is designed to easily include new functions written by the user in standard computer language (matlab or compiled form Fortan or C) . It therefore allows different users to share and control their tools of analyses, in the spirit of free software.