Abstract: A device and method for dynamically adapting spatial resolution for imager Fourier transform spectrometers makes it possible to acquire data in interferogram mode and image mode on survey points for an observed scene, each survey point being associated a matrix of macro-pixels and defined by a plurality of zones. For each survey point, analysis of the content of each zone is carried out on the basis of data of the image mode. Classification into clear zone or non-clear zone is carried out as a function of proportion of cloud, and clear-pixel data are generated on the basis of the sum of the data of the macro-pixels of the clear zone class. Survey point data are generated on the basis of the sum of the data of all the macro-pixels of the matrix associated with the survey point. The survey point and clear pixel data streams are transmitted to the ground.

Abstract: A method for correcting spatial response for an imaging Fourier transform spectrometer comprises the following steps: a prior step of calculation of the equalization parameters comprising a gain and an offset from data forming calibration scenes; a step of determination of equalization coefficients at a so-called pseudo superpixel level determining the gains and offsets at macropixel level from the data from a raw image that are collected by the imaging spectrometer in image mode, and gains and offsets determined in the prior step; and a step of equalization at pseudo superpixel level, applying the equalization coefficients to a macropixel from an acquisition in the interferogram mode of the imaging spectrometer in order to restore an equalized interferogram.

Abstract: A device and method for dynamically adapting spatial resolution for imager Fourier transform spectrometers makes it possible to acquire data in interferogram mode and image mode on survey points for an observed scene, each survey point being associated a matrix of macro-pixels and defined by a plurality of zones. For each survey point, analysis of the content of each zone is carried out on the basis of data of the image mode. Classification into clear zone or non-clear zone is carried out as a function of proportion of cloud, and clear-pixel data are generated on the basis of the sum of the data of the macro-pixels of the clear zone class. Survey point data are generated on the basis of the sum of the data of all the macro-pixels of the matrix associated with the survey point. The survey point and clear pixel data streams are transmitted to the ground.

Abstract: A method for correcting spatial response for an imaging Fourier transform spectrometer comprises the following steps: a prior step of calculation of the equalization parameters comprising a gain and an offset from data forming calibration scenes; a step of determination of equalization coefficients at a so-called pseudo superpixel level determining the gains and offsets at macropixel level from the data from a raw image that are collected by the imaging spectrometer in image mode, and gains and offsets determined in the prior step; and a step of equalization at pseudo superpixel level, applying the equalization coefficients to a macropixel from an acquisition in the interferogram mode of the imaging spectrometer in order to restore an equalized interferogram.

Abstract: A static interferometer comprises an entrance pupil, a splitter plate, a first mirror and a second mirror which are arranged in such a way that light beams originating from a collimated source are divided on the splitter plate, reflect on each of the mirrors and recombine while interfering at the output of the interferometer. The interferometer comprises a prismatic plate of index n comprising a variable thickness ej, the first beam passing through the prismatic plate before reflecting on a reflecting surface of the first mirror, the reflecting surface comprising a plurality of zones, each zone j being situated at a mean distance ?j from a reference plane. The reference plane being perpendicular to an optical axis and corresponding to a position of a plane mirror for which the optical path difference between the two interfering reflected beams is zero, each thickness ej being substantially equal to ?j·n/(n?1).

Abstract: The invention relates to a field-compensated interferometer (1) including an optical assembly (2) for directing incident light beams (4) having a field angle ? relative to an optical axis of the interferometer (1), into arms (5, 6) of the interferometer, and a beam splitter (12), the arms (5, 6) including at least one mechanically movable optical device (15, 16) for generating a variable optical path difference between beams generated by the separation of each incident beam (4) using said beam splitter (12), said interferometer (1) being characterized in that it includes at least one field compensation optical element (E) arranged in one or the other of the image focal planes of the optical assembly (2), said image focal planes being combined relative to the beam splitter (12), said element (E) including at least one surface (9) that is curved so as to generate a path difference between the incident beams having a non-zero field angle and the incident beams having a zero field angle, the generated path differ

Abstract: The invention pertains to a static interferometry system comprising two mirrors produced respectively by vertical assemblage (EH) and horizontal assemblage (EV) of a set of parallel plates of constant width, shifted along the optical axis so as to form stairs of variable optical path difference, the said two staircase mirrors (EH, EV) being disposed orthogonally so as to form, by optical superposition, a set of square facets engendering different optical path differences for the incident signal, and a detection device (DET) for detecting the set of optical path differences of the resulting interferogram. The system comprises, furthermore, means of continuous variation (LC) of the optical path difference during the acquisition of data by the detection device (DET), and sampling means (S, ACQL) for sampling the continuous optical path difference acquired while complying with the Nyquist criterion.

Abstract: A static interferometer comprises an entrance pupil, a splitter plate, a first mirror and a second mirror which are arranged in such a way that light beams originating from a collimated source are divided on the splitter plate, reflect on each of the mirrors and recombine while interfering at the output of the interferometer. The interferometer comprises a prismatic plate of index n comprising a variable thickness ej, the first beam passing through the prismatic plate before reflecting on a reflecting surface of the first mirror, the reflecting surface comprising a plurality of zones, each zone j being situated at a mean distance ?j from a reference plane. The reference plane being perpendicular to an optical axis and corresponding to a position of a plane mirror for which the optical path difference between the two interfering reflected beams is zero, each thickness ej being substantially equal to ?j·n/(n?1).

Abstract: A two-channel multiplex Fourier transform spectrometry interferometer device comprises two semi-reflecting mirrors substantially in alignment with each other between two reflecting surfaces substantially parallel to each other and to a mean plane containing the semi-reflecting mirrors. At least one of the mirrors and surfaces is inclined by a non-zero amount to the mean plane. The algebraic sum of the inclinations of the semi-reflecting mirrors relative to the mean plane is different than the sum of the inclinations of the reflective surfaces relative to said plane. At least one prismatic blade means with an index of refraction different than that of the remainder of the interferometer device is disposed between one of the semi-reflecting mirror and one of the reflective surfaces. The algebraic differences of the prismatic blade angles are different to either side of the mean plane. For earth spectrometry the device is mounted on an aircraft or a satellite, for example, moving relative to the earth.

Abstract: An interferometry device for Fourier transform multiplex spectrometric imaging designed to move relative to an object-zone according to a direction of motion constituting a reference direction for said interferometry device. The device includes a prismatic block of transparent material having a first and a second input/output face meeting in a block edge, a semitransparent plate inside said block, and first and second reflective surfaces forming a roof and arranged facing respectively the first and the second input/output face via the semitransparent plate. The device further has at least one slanted dioptrical separation surface with a dioptry angle (.alpha.) provided between one of the input/output faces and the corresponding reflective surface, and the deviation of the angles of inclination (.beta., .beta.') of the first and second rooflike reflective surfaces relative to the corresponding input/output face is non-zero.