Method, Device And Program For Processing Diffraction Images Of A Crystalline Material

A device for processing images of a material being crystalline or polycrystalline, comprising a diffraction detector making it possible to acquire:

• a first diffraction image of the material when the material is in a reference state, giving first digital pixel values as a function of two pixel coordinates,
• at least a second diffraction image of the material when the material is in a deformed state with respect to the reference state, the second image giving second digital pixel values as a function of the pixel coordinates,
• characterized in that the device comprises at least a calculator, comprising at least a memory, in which is stored a displacement field, for displacing pixels of the first image to pixels of a deformed image, as a function of:
• the two pixel coordinates,
• predetermined coordinates of a center, corresponding to a normal projection, in an image plane of the detector, of a source point (S) of the beam diffracted in the material, and
• components of an elastic deformation gradient tensor,
• the calculator being configured for:
• during a first computing step, making the current elastic deformation gradient tensor take a determined value,
• during a second computing step, computing the current displacement field on the basis of the current elastic deformation gradient tensor and of the coordinates for each of the pixels of the first image,
• during a third computing step, computing third digital pixel values of a deformed image by applying the second image to the pixel coordinates to which the current displacement field has been added,
• over an iterative algorithm, making iterations of the first, second and third computing steps on reupdated determined tensor values, until a criterion of convergence on the determined value of the elastic deformation gradient tensor is fulfilled, to compute the corresponding displacement field.