1. A method for measuring movement and/or deformation of a study part ( 150 ) subjected to an external stress, said method implementing a color digital image acquisition device ( 110 ) and image correlation means, comprising the steps of: applying an external stress on said study part ( 150 ), acquiring ( 250 ) a plurality of color digital images ( 500 ) of the surface of the study part ( 150 ) by means of the color digital image acquisition device ( 110 ) while applying the external stress on said study part ( 150 ), processing ( 260 ) of the color digital images ( 500 ) acquired in the step of acquisition ( 250 ) of a plurality of color digital images ( 500 ) so as to highlight contrasting details on variable scales, and correlating ( 270 , 280 ) all of the processed digital images ( 260 ) to determine the fields of movement on the scales associated with each processing operation ( 260 ).