  A new approach for decoding directly strains from surfaces encoded with
random patterns has been developed and validated. It is based on phase analysis
of small region of interest. Here we adapt to random patterns new concepts
proposed by Badulescu (2009) on the grid method. First metrological results are
encouraging: resolution is proportional to strain level, being 9% of the
nominal value, for a spatial resolution of 9 pixels (ZOI 64 \times 64 pixels2).
Random noise has to be carefully controlled. A numerical example shows the
relevance of the approach. Then, first application on a carbon fiber reinforced
composite is developed. Fabric intertwining is studied using a tensile test.
Over-strains are clearly visible, and results connect well with the previous
studies
