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Data format

A standardisation of the data format has been recently performed, allowing compatibility with other applications. It is described at http://www.civproject.org. The raw images are stored in the compressed (reversible) form '.png' , which saves a factor about 3 in memory, and can be read directly with standard image software. The output fields are stored in the 'netcdf' format which can be read directly by all computers (without problems with number coding), and which provides a clear information of the relevant parameters, allowing to track back the processing steps.

In the ``acquire'' menu of Civit(2.6), once the generic name (for instance ``aa'') has been set , a directory ``aa'' is created, including the successive image files aa001a, aa001b, aa001c,aa001d, for burst number 1, and similarly for the successive bursts.

The experimental parameters are recorded in a text file aa.civ with the following format.

278 ......................................number of bursts

1024 1024..........................pixel number in x and y

4 .........................................number of images in a burst

1 .........................................not relevant

0.066667 ..........................frame period of the camera

4.080000 4.080000.........scale in pixels/cm along x and y

4.080000 4.080000.........same

1 ........................................1 indicates 2D CIV

1 0.000000 7 17 56 1

2 10.666694 7 17 56 1

3 21.333498 7 17 56 1 ..................... burst number, time elpased from the beginning (in s), successive time intervals \( t_{1}t_{2}t_{3} \) in frame periods.

Each image file can be read with the Matlab programme (6) (for the old, uncompressed image files) .P


next up previous contents
Next: CIV processing step by Up: Processing software: Previous: Hierarchical algorithm   Contents
Joel Sommeria 2003-02-14