Method and system for guiding a user holding in one hand an ultrasound observation probe towards a pre-recorded acoustic window

A method for guiding a user holding in one hand a probe configured for ultrasound observation of a body of a patient, the probe being provided with a first object secured to the probe, the first object comprising first markers on the surface of the first object, the probe being held in a current position and according to a current direction, a display device configured to receive at least one image acquired by a camera configured to observe in its field the probe, the first object, and a second object comprising second markers on the surface of the second object, the user being guided towards a recorded position and a recorded direction of the probe, the method comprising the following steps:

• placing a support at a predetermined point of a surface of the patient's body observed with the probe, the support being configured to receive on a surface of the support the second object by maintaining the second object in a predetermined position and orientation of the second object relative to a fixed reference frame relative to the patient's body;
• placing the second object on the surface of the support, so that the second object is maintained in a predetermined position and orientation relative to the reference frame fixed relative to the patient's body;
• acquiring at least one image with the camera;
• determining the reference frame, from the second markers identifiable by processing the at least one image, the recorded position and the recorded direction of the probe being defined in the reference frame;
• in the reference frame, determining coordinates of at least one first point corresponding to a vertex of a polygon disposed in a first plane transverse to the recorded direction of the probe, such that a central area of the polygon is crossed by a straight line parallel to the recorded direction of the probe and passing through the recorded position of the probe;
• displaying the at least one image on the display device;
• projection, in augmented reality on the at least one displayed image, the at least one first point;
• determining the current position and the current direction of the probe in the reference frame, from the first markers identifiable by another processing of the at least one image;
• determining coordinates in the reference frame of at least one second point, the at least one second point corresponding to the vertex of the polygon placed in a second plane transverse to the current direction of the probe, so that a central area of the polygon is crossed by a straight line parallel to the current direction of the probe and passing through the current position of the probe:
• projecting, in augmented reality onto the at least one displayed image, the at least one second point;
• bringing the probe into a new current position and a new current direction so that a new projection in augmented reality of the at least one second point corresponding to the vertex of the polygon disposed in a new second plane transverse to the new current direction of the probe, a central area of the polygon being crossed by a straight line parallel to the new current direction of the probe and passing through the new current position of the probe, the new projection being closer to the projection of the at least one first point than to the projection of the at least one second point, until the at least one second point and the at least one first point coincide, and thus the new current position and the new current direction coincide with the recorded position and the recorded direction, the projection and new projection in augmented reality steps of the at least one second point being produced in real time as the probe is displaced.