L'échotomographie analogique. Etude de la reconstruction acousto-optique à partir de données échographiques

Tomography has been a highly active research field for the last 20 years and great progress has been made in numerical reconstruction methods. This paper deals with a new method of tomographic reconstruction based on optical processing. We first present a system of acquisition by ultrasound and then the backprojection procedure which is performed by optical methods. The projections are coded by an opto-acoustic modulator and deflector into a laser beam and the image is obtained by integrating the resulting pattern over one revolution by a CCD camera. This procedure, which is entirely analogical, allows the real time reconstruction of images, the only delay being the time required for the aquisition (approximatively 1 sec.). Echotomographies obtained by this method are presented