Method for the reconstructive multi-spectral imaging of a primary source , using a fixed or moveable instrument, characterised in that it comprises: - measuring the intensity of the light, in the vicinity of a focal plane of an optic , coming from a secondary optical source obtained by acousto-optic diffraction of the light in an acousto-optic device originating from the primary optical source , - acquiring said measurements of the intensity of the light from said secondary optical source by means of an array of one or two-dimensional pixelated sensors located in the vicinity of said focal plane , - calibrating using a monochromatic primary source , consisting of measuring for each pixel (m), in the focal plane , the acoustic frequency fa corresponding to the wavelength of said monochromatic primary source and producing an acousto-optic diffraction at the point (m), - determining, by using this calibration and the a priori knowledge of the variation of the optical indices of the material constituting the acousto-optic device with the wavelength (λ), of the function f2(m,λ) supplying for any wavelength (λ) and any image point (m) the value of the acoustic frequency producing said acousto-optic diffraction of the wavelength (λ) at the pixel (m), - acquiring multi-spectral images by a combination of acquisitions of the aforesaid pixelated sensors, either for a series of distinct acoustic frequencies, or by a relative movement of the instrument in relation to the primary source or by a combination of series of said frequencies and of said movement, an intensity sought for each point (M) of the primary source I M λ = Im f 1 M λ t , f 2 f 1 M λ t , λ being obtained from the intensity measured Im at the pixel m corresponding to the point (M) of the primary source , from the knowledge of the aforesaid function f2(m,λ) and, for each acquisition, of the relation f1 between each point (M) of the primary source and each pixel (m). - measuring the intensity of the light, in the vicinity of a focal plane of an optic , coming from a secondary optical source obtained by acousto-optic diffraction of the light in an acousto-optic device originating from the primary optical source , - acquiring said measurements of the intensity of the light from said secondary optical source by means of an array of one or two-dimensional pixelated sensors located in the vicinity of said focal plane , - calibrating using a monochromatic primary source , consisting of measuring for each pixel (m), in the focal plane , the acoustic frequency fa corresponding to the wavelength of said monochromatic primary source and producing an acousto-optic diffraction at the point (m), - determining, by using this calibration and the a priori knowledge of the variation of the optical indices of the material constituting the acousto-optic device with the wavelength (λ), of the function f2(m,λ) supplying for any wavelength (λ) and any image point (m) the value of the acoustic frequency producing said acousto-optic diffraction of the wavelength (λ) at the pixel (m), - acquiring multi-spectral images by a combination of acquisitions of the aforesaid pixelated sensors, either for a series of distinct acoustic frequencies, or by a relative movement of the instrument in relation to the primary source or by a combination of series of said frequencies and of said movement, an intensity sought for each point (M) of the primary source I M λ = Im f 1 M λ t , f 2 f 1 M λ t , λ being obtained from the intensity measured Im at the pixel m corresponding to the point (M) of the primary source , from the knowledge of the aforesaid function f2(m,λ) and, for each acquisition, of the relation f1 between each point (M) of the primary source and each pixel (m). <EOS>