System for analysing a transparent sample with control of position, and associated method

A system for analyzing a particle of interest of a biological sample, comprising:

• an analysis pathway, comprising a first light source emitting an analysis light beam, and a first optical system configured to focus the analysis light beam in a plane orthogonal to the optical axis thereof, as a focusing plane;
• a position control pathway, comprising a second light source, an image sensor, and a second optical system at least partially merged with the first optical system such that the first optical system and the second optical system comprise a shared optical system;
• and
• computing means configured to compute, by numerical propagation, at least one image, reconstructed from an image provided by the image sensor;
• wherein the image sensor is offset relative to an image of the focusing plane by the second optical system;
• wherein the computing means comprises means for comparing a control image with a focused reconstructed image, the focused image being associated with a minimum offset between a position of a corresponding reconstruction plane, and a plane receiving an image of the particle of interest by the second optical system.

A system for analyzing a particle of interest of a biological sample, comprising:

• an analysis pathway, comprising a first light source emitting an analysis light beam, and a first optical system configured to focus the analysis light beam in a plane orthogonal to the optical axis thereof, as a focusing plane;
• a position control pathway, comprising a second light source, an image sensor, and a second optical system at least partially merged with the first optical system such that the first optical system and the second optical system comprise a shared optical system;
• computing means configured to compute, by numerical propagation, at least one image, reconstructed from an image provided by the image sensor;
• and
• means for thresholding a reconstructed image, the threshold being defined by ith=iav+3σ wherein iav is mean value of intensity of the pixels in the reconstructed image and σ is standard deviation of the intensity of the pixels in the reconstructed image;
• wherein the image sensor is offset relative to an image of the focusing plane by the second optical system.