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US 5,174,298 AGranted
Imaging process and system for transillumination with photon frequency marking
AssigneeGeneral Electric CGR S.A.
InventorsDaniel Dolfi, Francois Micheron
Life of this patent
Estimating the term…
Abstract
In an imaging process and system by transillumination of a medium illuminated by transparency by a beam, an acoustic transducer emits an acoustic wave in the medium which interferes with the beam. The frequency of the light passing through the medium is then shifted from the value of the frequency of the acoustic wave. A collimating device whose object focus is located at the intersection of the acoustic wave and the light beam collects the light diffused by the medium.
Claims24
A transillumination imaging method comprising:
- transmitting a first light beam (F1) into at least one scattering zone within a medium (H) to be imaged;
- transmitting into said scattering zone within said medium at least first and second acoustic waves having a first frequency (f.sub.1) and a second frequency (f.sub.2), respectively, wherein the first frequency (f.sub.1) and the second frequency (f.sub.2) are different and the at least first and second acoustic waves interfere with the first light beam (F1), with the second acoustic wave interfering with the first light beam after the first acoustic wave interferes with the first light beam, thereby producing a second light beam (F2) produced by interference of said first and second acoustic waves with said first light beam;
- producing a reference beam to interfere with the second light beam;
- and
- applying said second light beam and said reference to a detector and measuring a quantity of light scattered by said scattering zone by detecting a light which has been subjected to a translation of the first frequency (f.sub.1) and the second frequency (f.sub.2).
2 more elements
A system for transillumination imaging of a medium comprising:
- laser means for illuminating a scattering zone in the medium by means of a first laser beam having a first frequency (F1);
- at least first and second acoustic transducers mounted adjacent to each other for emitting within the medium respective acoustic waves which are not collinear with the first laser beam and which have respective predetermined frequencies (f.sub.1, f.sub.2), said acoustic waves intercepting and interfering with said first laser beam (F1) in said scattering zone;
- an optical collimator, placed in the path of said first laser beam and having an object focus located at said scattering zone in said medium for collimating light of said first laser beam which is intercepted by said acoustic waves from said at least first and second acoustic transducers, which produces a collimated second laser beam (F2);
- said laser means comprising means for producing a reference laser beam (F3) to interfere with said second laser beam;
- and
- a detector optically coupled to said reference laser beam and said collimated second laser beam for measuring the quantity of light scattered in said scattering zone, including frequency filtering means for detecting light of the collimated second laser beam which has been subjected to a frequency translation relative to said first frequency due to interference with said first and second acoustic waves;
- said second acoustic transducer mounted adjacent the first acoustic transducer and positioned on the opposite side of the first transducer with respect to the side of the medium on which the light beam is incident, the second acoustic wave emitted by said second transducer interfering with the first light beam but not interfering with the first acoustic wave and irradiating the medium downstream of where the medium is irradiated by said first acoustic wave with respect to the side of the medium on which the first light beam is incident.
4 more elements
Dependencies are inferred from the claim text.