Abstract: A method for observing a sample is provided, including illuminating the sample with a light source and forming a plurality of images, by an imager, the images representing the light transmitted by the sample in different spectral bands. From each image, a complex amplitude representative of the light wave transmitted by the sample is determined in a determined spectral band. The method further includes backpropagation of each complex amplitude in a plane passing through the sample, determining a weighting function from the back-propagated complex amplitudes, propagating the weighting function in a plane along which the matrix photodetector extends, updating each complex amplitude, in the plane of the sample, according to the weighting function propagated.

Abstract: A method for identifying a state of a cell contained in a sample, including: illuminating the sample using a light source by producing an incident light wave propagating toward the sample; then acquiring, using a matrix-array photodetector, an image of the sample, the sample being placed between the light source and the matrix-array photodetector such that the matrix-array photodetector is exposed to a light wave resulting from interference between the incident light wave and a diffraction wave produced by each cell; applying a numerical reconstruction algorithm to the image acquired by the matrix-array photodetector, to estimate a characteristic quantity of the light wave reaching the matrix-array detector, at a plurality of distances from the matrix-array photodetector. The value of the characteristic quantity, or its variation as a function of distance, allows the state of the cell to be determined from among predetermined states.

Abstract: A method for identifying a particle contained in a sample, including illuminating the sample using a light source, the light source producing an incident light wave propagating toward the sample, then acquiring, using a matrix-array photodetector, an image of the sample, the sample being placed between the light source and the photodetector such that the matrix-array photodetector is exposed to a light wave that is the result of interference between the incident light wave and a diffraction wave produced by each particle. The method further includes applying a numerical reconstruction algorithm to the image acquired by the photodetector, to estimate a characteristic quantity of the light wave reaching the detector, at a plurality of distances from the detector. The variation in the characteristic quantity as a function of distance allows the particle to be identified.

Abstract: A method reconstructing the optical properties of a medium using a reconstruction system has a radiation source lighting the medium and a detector receiving a signal transmitted by the medium. The steps include lighting the medium using a radiation source, receiving by the detector of a signal emitted by the medium, and processing, for a source-detector pair, of a first distribution of the signal received by the corresponding detector. Then computing the Mellin-Laplace transform, for a given order and a given variable, of a magnitude comprising the first distribution, the order being an integer, the variable being a real number, and reconstructing optical properties of the medium using the Mellin-Laplace transform of said magnitude. The computation step includes computing a plurality of Mellin-Laplace transforms of the magnitude for distinct values of the order, and the reconstruction step is carried out from a combination of the plurality of Mellin-Laplace transforms.

Abstract: Method and device for measuring the multi-dimensional distribution of optical characteristics of an object, by carrying out the following operations: illumination of the object by means of a pulsed light source; and acquisition of an image by modulated detection of light rays coming from the object consecutively to the illumination, the detection being modulated according to an acquisition modulation function G(t) which is continuous, non-sinusoidal and temporal, the acquisition taking place outside the phase of illumination by the light source.

Abstract: The invention concerns a method for locating at least one absorber in a diffusing medium, using at least one excitation radiation and at least one detector (?fluo), including: a) for at least one pair (radiation source-detector), at least one excitation by the radiation source, and at least one detection of the fluorescence signal emitted by the absorber after this excitation, b) identification of meshing of the volume into mesh elements, and c) estimation of the location of the absorber in its diffusing medium, by computing a function (Pm) of at least one of three parameters.

Abstract: The invention concerns a method for locating at least one absorber in a diffusing medium, using at least one excitation radiation and at least one detector (?fluo), including: a) for at least one pair (radiation source-detector), at least one excitation by the radiation source, and at least one detection of the fluorescence signal emitted by the absorber after this excitation, b) identification of meshing of the volume into mesh elements, and c) estimation of the location of the absorber in its diffusing medium, by computing a function (Pm) of at least one of three parameters.

Abstract: The invention concerns a method for locating at least one fluorophore or at least one absorber in a diffusing medium, using at least one excitation radiation and at least one fluorescence detector (?fluo), comprising: a) for at least one pair (radiation source-detector), at least one excitation by the radiation source, and at least one detection of the fluorescence signal emitted by the fluorophore after this excitation, b) identification of meshing of the volume into mesh elements, c) estimation of the location of the fluorophore or absorber in its diffusing medium, by computing a function (Pm) of at least one of three parameters.

Abstract: A method for locating at least one fluorescent tag in a scattering medium, wherein: a) at least one tag is introduced into the medium, b) a fluorescence image is performed by an infrared excitation of the medium along a first axis, the image including a fluorescence component due to the tag, and an auto-fluorescence component due to a medium part other than the tags, c) the image is processed by factorizing into two non-negative matrices, and d) an image of the distribution of the tag(s) is determined, without the auto-fluorescence component.

Abstract: The method enables a non-homogeneous diffusing object to be examined by illuminating the object with a continuous light by means of a light source. It previously comprises reconstruction of the three-dimensional spatial mapping of an attenuation variable representative of the diffusion and absorption non-homogeneities of the object, by resolving a diffusion equation ?2F({right arrow over (r)}S, {right arrow over (r)})?k?2({right arrow over (r)})F({right arrow over (r)}S, {right arrow over (r)})=AS?({right arrow over (r)}?{right arrow over (r)}S). In the diffusion equation, AS is a constant, {right arrow over (r)} the spatial coordinate of any point of the mesh of a volume at least partially containing the object, and {right arrow over (r)}S the spatial coordinate of the light source. The transfer functions of an equation used for reconstructing the distribution of fluorophores integrate the attenuation variable reconstituted in this way.

Abstract: The invention concerns a method for locating at least one fluorophore or at least one absorber in a diffusing medium, using at least one excitation radiation and at least one fluorescence detector (?fluo), comprising: a) for at least one pair (radiation source-detector), at least one excitation by the radiation source, and at least one detection of the fluorescence signal emitted by the fluorophore after this excitation, b) identification of meshing of the volume into mesh elements, c) estimation of the location of the fluorophore or absorber in its diffusing medium, by computing a function (Pm) of at least one of three parameters.

Abstract: To examine a plate-shaped object comprising fluorophores and having a first face and an opposite second face, the method comprises a first sequential illumination step of the first face of the object with a fluorophore excitation light and a first sequential acquisition step of a first series of images by detecting light emitted by the second face of the object. The density of the lighting points is lower than the density of the detection points and the method further comprises a second sequential illumination step of the second face of the object with a fluorophore excitation light and a second sequential acquisition step of a second series of images by detecting light emitted by the first face of the object. Reconstruction of the three-dimensional fluorophore distribution image in the object is performed by means of the first and second series of images.

Abstract: Method and device for measuring the multi-dimensional distribution of optical characteristics of an object, by carrying out the following operations: illumination of the object by means of a pulsed light source; and acquisition of an image by modulated detection of light rays coming from the object consecutively to the illumination, the detection being modulated according to an acquisition modulation function G(t) which is continuous, non-sinusoidal and temporal, the acquisition taking place outside the phase of illumination by the light source.

Abstract: The method enables a heterogeneous object containing fluorophores to be examined. A first face of the object is illuminated with an excitation light exciting the fluorophores. The light emitted by a second face of the object, opposite the first face, is detected by means of a matrix of detectors. The fluorophore distribution is determined by means of relevant Green's functions each associated with a selected source and/or detector, able to be assimilated to a point of the surface of the object. Thus, a first spatial coordinate of each of the relevant Green's functions corresponds to a point of the first face of the object and/or a second spatial coordinate of each of the relevant Green's functions corresponds to a point of the second face of the object.

Abstract: The method enables a non-homogeneous diffusing object to be examined by illuminating the object with a continuous light by means of a light source. It previously comprises reconstruction of the three-dimensional spatial mapping of an attenuation variable representative of the diffusion and absorption non-homogeneities of the object, by resolving a diffusion equation ?2F({right arrow over (r)}S, {right arrow over (r)})?k?2({right arrow over (r)})F({right arrow over (r)}S, {right arrow over (r)})=AS?({right arrow over (r)}?{right arrow over (r)}S). In the diffusion equation, AS is a constant, {right arrow over (r)} the spatial coordinate of any point of the mesh of a volume at least partially containing the object, and {right arrow over (r)}S the spatial coordinate of the light source. The transfer functions of an equation used for reconstructing the distribution of fluorophores integrate the attenuation variable reconstituted in this way.

Abstract: To examine a plate-shaped object comprising fluorophores and having a first face and an opposite second face, the method comprises a first sequential illumination step of the first face of the object with a fluorophore excitation light and a first sequential acquisition step of a first series of images by detecting light emitted by the second face of the object. The density of the lighting points is lower than the density of the detection points and the method further comprises a second sequential illumination step of the second face of the object with a fluorophore excitation light and a second sequential acquisition step of a second series of images by detecting light emitted by the first face of the object. Reconstruction of the three-dimensional fluorophore distribution image in the object is performed by means of the first and second series of images.

Abstract: The method enables a heterogeneous object containing fluorophores to be examined. A first face of the object is illuminated with an excitation light exciting the fluorophores. The light emitted by a second face of the object, opposite the first face, is detected by means of a matrix of detectors. The fluorophore distribution is determined by means of relevant Green's functions each associated with a selected source and/or detector, able to be assimilated to a point of the surface of the object. Thus, a first spatial coordinate of each of the relevant Green's functions corresponds to a point of the first face of the object and/or a second spatial coordinate of each of the relevant Green's functions corresponds to a point of the second face of the object.

Abstract: The invention relates to a method for x-ray examination of an object where two categories of materials are taken into consideration, comprising: the use of broad spectrum x-rays; measurements of the x-rays by bands of the spectrum; expressions ({circumflex over (M)}) of thicknesses or masses of the two categories of materials passed through by the x-rays, the expressions ({circumflex over (M)}) being functions of at least two of the measurements (mesk) and coefficients (A); and applying a selection criterion from among the expressions ({circumflex over (M)}) to deduce from this an expression (final {circumflex over (M)}) considered true; characterized in that the selection criterion comprises a combination (f) of the expressions with weighting factors (a), and a calculation of the weighting factors such that the combination has minimal variation according to variations of the measurements.

Abstract: The invention relates to a method for x-ray examination of an object where two categories of materials are taken into consideration, comprising: the use of broad spectrum x-rays; measurements of the x-rays by bands of the spectrum; expressions (M?) of thicknesses or masses of the two categories of materials passed through by the x-rays, the expressions (M?) being functions of at least two of the measurements (mesk) and coefficients (A); and applying a selection criterion from among the expressions (M?) to deduce from this an expression (final M?) considered true; characterized in that the selection criterion comprises a combination (f) of the expressions with weighting factors (a), and a calculation of the weighting factors such that the combination has minimal variation according to variations of the measurements.

Abstract: This radiography process utilizes dual-energy rays and comprises, in order to differentiate bone, lean and fatty tissues at the same time, an improvement consisting in assessing the total length penetrated by each ray while correcting the errors which may be produced by internal gas pockets. One proceeds as follows: selection of certain rays which have not penetrated bone tissues; calculation of the thicknesses of lean and fatty tissues penetrated by these rays according to the two attenuations, the sum of these two thicknesses being the length of attenuation; estimation of the length of attenuation elsewhere, in particular by means of interpolations; and calculation of the thicknesses of the three categories of tissues penetrated according to this total length of attenuation and the two attenuations.