METHOD FOR ACOUSTO-OPTIC IMAGING BY FOURIER RECONSTRUCTION USING A FLAT WAVE AS A CARRIER WAVE OF THE ULTRASONIC WAVE

摘要

ABSTRACTA system for acousto-optic imaging of an observation zone (3), comprising: • a set of ultrasonic transducers (1) aligned in at least one alignment direction able to together produce an ultrasonic wave (2) in the observation zone (3), propagating in a propagation direction (Dz) orthogonal to the at least one alignment direction of the ultrasonic transducers (1); • a light source (4) producing an incident light wave (5) encountering said ultrasonic wave in the observation zone in order to produce marked photons (6); • a control device (7) configured to control each ultrasonic transducer (1) with an ultrasonic frequency control signal; • a system (8) for detecting some of the marked photons, said marked photons carrying a temporal modulation transmitted by the ultrasonic wave encountering the light wave; • a means (10) for processing an acousto-optic acquisition signal (9) received from the detection system, which means is able to demodulate said acousto-optic acquisition signal; the control device (7) being configured to control each ultrasonic transducer using the control signal, said control signal being formed by an ultrasonic frequency carrier (fus), the carrier being identical for all the transducers so as to generate a flat wave propagating in the propagation direction (Dz), and being modulated by a periodic temporal modulation signal with a given temporal frequency and the same shape for all the ultrasonic transducers (1), said temporal modulation signal having a phase shift, the value of which is specific to each ultrasonic transducer and which is dependent on the position of the ultrasonic transducers (1), so that the flat ultrasonic wave emitted by the set of ultrasonic transducers (1) has a modulation, which has a spatial periodicity in the at least one alignment direction of the transducers, the value of which is determined by the function between the phase shift and the position of the ultrasound transducers; - generating various flat ultrasonic waves corresponding to various values of the given temporal frequency of the temporal modulation signal; and - generating, for each given temporal frequency, various functions connecting the phase shift and the position of the ultrasonic transducers (1), so that the processing means (10): • determines Fourier components of an acousto-optic image (21) of the observation zone (3); and • constructs said acousto-optic image (21) by inverse Fourier transform of the Fourier components.