Device and method for acquiring a particle present in a sample

A device of acquisition of a plurality of particles present in a sample, said acquisition device comprising:

• a spatially coherent or pseudo-coherent light source directed towards a first surface of said sample;
• an optical system having an optical axis and achieving the conjugation between a plane of focus and a focal plane, directed towards a second surface of said sample opposite to said first surface, and placed relative to the sample so that the particles are not in the plane of focus;
• an image sensor placed in the focal plane of the optical system and configured to acquire an intensity image (Ih) formed by the interference between said light source and said sample;
• and
• a computational processing unit comprising:
• a unit of digital construction of a series of electromagnetic matrices (I1-IN) modeling, from the acquired image (Ih), an electromagnetic wave in planes parallel to the plane of focus and comprised in the sample for a plurality of offsets relative to said plane,
• a unit for determining a first electromagnetic matrix (Ifmoy) at an average distance of focus on the particles from the series of electromagnetic matrices (I1-IN);
• a unit for identifying at least one of the particles in the first electromagnetic matrix (Ifmoy) and for storing the coordinates of said particle;
• and
• a unit for determining a second electromagnetic matrix (Ifp) at a distance of focus on a particle identified from the components of the series of electromagnetic matrices (I1-IN) having the stored coordinates.