Abstract This invention relates to spectral zonal photography in which spectral zones of a scene are stored with unique respective carrier modulations on a colorblind photostorage medium such as a black-and-white panchromatic film from which the scene can be reconstructed in color by Fourier transform techniques with spatial and spectral filtering, and in particular to methods and means to effect such storage without the intervention of a plurality of separate individual images of the scene. Each of several spectral zones is modulated with a periodic function, such as a grating having a unique orientation relative to the scene. Embodiments are disclosed in which these zones and their respective modulations can be stored in sequence or simultaneously. Unique spectral zonal filters are disclosed for simultaneous storage of several spectral zones of a scene. In one aspect of the invention such filters can be employed in direct contact with the storage medium. In another embodiment. Fourier transform techniques are employed with spatial and spectral filtering to effect simultaneous storage of several spectral zones of a scene. In all embodiments the final storage of colorcoded information in a colorblind storage medium is useful to reconstruct the original scene in the original colors or in any desired portion or portions of the visible spectrum by means of Fourier transform and filtering techniques. The reconstructed scene can be viewed in full color or recorded on a colorsensitive medium.
A substantially two-dimensional light modulation filter for use in preparing from colored light representing a scene an image transparency suitable for producing by Fourier transform and spatial and spectral filtering techniques a projected image of said scene in prescribed colors, which may be natural or artificial, from ''''n'''' light components representing respective spectral zones of said colored light where ''''n'''' is an integer greater than one, said filter having a plurality of ''''n'''' periodic functions each extending throughout the area of said filter and having a unique azimuthal characteristic in the area of the filter for passing light representative of a unique wavelength band corresponding to a selected one of said spectral zones, said functions overlapping each other, the configuration of said functions being such that the light transmittance of said filter is expressed as the product: (x, lambda ) P (x) .P (x) .--P (x) Where: (x, lambda ) is the mathematical representation of the total filter with transmittance a function of spatial coordinates x and wavelength lambda ; P (x) is the periodic function corresponding to the wavelength band lambda i with azimuthal characteristic Alpha i; and lambda i is the average wavelength in the band from lambda i- Delta lambda i to lambda i + Delta lambda i, each periodic function being comprised of periodic alternately spectrally neutral elements and color filter elements capable of passing light limited to a unique wavelength band corresponding respectively to a selected one of said spectral zones, said neutral elements and said color filter elements occupying different fractions of the period length of said function such that light in said unique wavelength band is transmitted through said filter in a minor fraction of said period length and substantially blocked in a major fraction of said period length, said minor fraction being substantially smaller than said major fraction.
Claim 2
Dependent Claim
306 words
A substantially two-dimensional light modulation filter for use in preparing from colored light representing a scene an image transparency suitable for producing by Fourier transform and spatial and spectral filtering techniques a projected image of said scene in prescribed colors, which may be natural or artificial, from ''''n'''' light components representing respective spectral zones of said colored light where ''''n'''' is an integer greater than one, said filter having a plurality of ''''n'''' periodic functions each extending throughout the area of said filter and having a unique azimuthal characteristic in the area of the filter for passing light representative of a unique wavelength band corresponding to a selected one of said spectral zones, said functions overlapping each other, the configuration of said functions being such that the light transmittance of said filter is expressed as the product: (x, lambda ) P (x) .P (x) .--P (x) Where: (x, lambda ) is the mathematical representation of the total filter with transmittance a function of spatial coordinates x and wavelength lambda ; P (x) is the periodic function corresponding to the wavelength band lambda i with azimuthal characteristic Alpha i; and lambda i is the average wavelength in the band from lambda i- Delta lambda i to lambda i + Delta lambda i, each periodic function being comprised of periodic alternately spectrally neutral elements and color filter elements capable of passing light limited to a unique wavelength band corresponding respectively to a selected one of said spectral zones, said neutral elements and said color filter elements occupying different fractions of the period length of said function such that light in said unique wavelength band is transmitted through said filter in a minor fraction of said period length and substantially blocked in a major fraction of said period length, said minor fraction being substantially smaller than said major fraction.
Claim 3
Dependent Claim
22 words
The filter defined by claim 1 wherein said neutral elements are substantially totally transmissive and said color filter elements are subtractive primaries.
Claim 4
Dependent Claim
13 words
The filter defined by claim 2 wherein said minor fraction is substantially one-tenth.
Claim 5
Dependent Claim
21 words
The filter defined by claim 1 wherein said neutral elements are substantially opaque and said color filter elements are additive primaries.
Claim 6
Dependent Claim
13 words
The filter defined by claim 4 wherein said minor fraction is substantially one-tenth.