Optical spatial filtering with multiple light sources

Claim 2

An optical system for modifying the projected image of an image-bearing photographic transparency and defining an optic axis, comprising: means for directing a plurality of light beams at said transparency, each of said light beams being displaced from said optic axis and having a luminous intensity substantially equal to that of a source of illumination and on passing through said transparency generating in a common image plane a discrete spatial spectrum of light comprising a zero-order and higher order spatial frequencies; and means arranged relative to said common image plane for projecting relative to said optic axis and on an imagereceiving plane the light beams of zero-order spatial frequency as uniform illumination and the light beams of higher order spatial frequencies as fine, medium and broad details of said transparency image and for varying the luminous intensity of at least one of said zero and higher order spatial frequencies, thereby modifying at least one of the details of said projected image and enhancing the image contrast.

Claim 3

The system in accordance with claim 1 wherein said directing means is arranged relative to said transparency and includes a light source positioned with respect to each of a plurality of small apertures in an opaque plate for producing generally point sources of light and a condenser lens system for directing the light emanating from said point sources at said transparency.

Claim 4

The system in accordance with claim 2 wherein said point sources are formed by a tungsten filament lamp positioned relative to each of said apertures.

Claim 5

The system in accordance with claim 2 wherein said light source is generally coherent.

Claim 6

The system in accordance with claim 2 wherein said light source comprises a zirconium concentrated arc lamp that is partially coherent spatially and positioned relative to each of said apertures.

Claim 7

The system in accordance with claim 1 wherein said projecting means comprises a projection lens system with said common image plane generally near said projection lens system and spatial filtering means positioned in said common image plane.

Claim 8

The system in accordance with claim 6 wherein said spatial filtering means includes more than one light-attenuating area positioned in said common image plane so as to intercept at least the light beams of zero-order spatial frequency.

Claim 9

The system in accordance with claim 7 wherein said areas comprise a plurality of discrete light-attenuating areas in said common image plane, each of which is generally in registry with a respective one of the light beams of zero-order spatial frequency.

Claim 10

An optical system for modifying the projected image of an image-bearing photographic transparency, comprising: means forming a plurality of light beams of substantially equal luminous intensity; means for mounting said transparency relative to said light beams so as to intercept each of said light beams; a condenser lens arranged in the path of said light beams and relative to said transparency, each of the light beams passing through said transparency generating a discrete spatial spectrum in a common image plane comprisIng a zero-order and higher order spatial frequencies; a lens system arranged relative to said common image plane for projecting relative to a common optical axis and onto an image-receiving plane the light beams of zero-order spatial frequency as uniform illumination and the light beams of higher order spatial frequencies to produce said projected image comprising the fine, medium and broad details of said transparency image; and spatial filtering means arranged generally in said common image plane to intercept said spectra and having more than one light-attenuating area intercepting the light beams of zero-order spatial frequency for reducing the intensity thereby increasing the contrast of at least one of the fine and medium details relative to the broad details of said projected image.

Claim 11

An optical system for modifying the projected image of an image-bearing photographic transparency, comprising: means forming a plurality of light beams of substantially equal luminous intensity; means for mounting said transparency relative to said light beams so as to intercept each of said light beams; a condenser lens arranged in the path of said light beams and relative to said transparency, each of the light beams passing through said transparency generating a discrete spatial spectrum in a common image plane comprisIng a zero-order and higher order spatial frequencies; a lens system arranged relative to said common image plane for projecting relative to a common optical axis and onto an image-receiving plane the light beams of zero-order spatial frequency as uniform illumination and the light beams of higher order spatial frequencies to produce said projected image comprising the fine, medium and broad details of said transparency image; and spatial filtering means arranged generally in said common image plane to intercept said spectra and having more than one light-attenuating area intercepting the light beams of zero-order spatial frequency for reducing the intensity thereby increasing the contrast of at least one of the fine and medium details relative to the broad details of said projected image.

Claim 12

The system in accordance with claim 9 wherein said forming means comprises a plurality of light sources, each of which is arranged relative to a respective small aperture in an opaque plate such that the light beam transmitted by each aperture is at least partially coherent spatially within its respective beam and generally incoherent with respect to every other light beam.

Claim 13

The system in accordance with claim 10 wherein the light emanating from each of said plurality of light sources is directed to said condenser lens system by a respective internal light transmitting medium.

Claim 14

The system in accordance with claim 9 wherein each of said light beams is formed by a tungsten filament lamp arranged at a small angle to the optical axis of said system and with respect to each of a plurality of apertures in an opaque plate.

Claim 15

The system in accordance with claim 9 wherein said spatial filtering means includes more than one light-attenuating area positioned in said common image plane so as to intercept at least the light beams of zero-order spatial frequency.

Claim 16

The system in accordance with claim 9 wherein said spatial filtering means includes an area of light-attenuating material positioned in said common image plane and in registry with a respective one of each light beam of zero-order spatial frequency.

Claim 17

The system in accordance with claim 9 wherein said attenuating area will absorb between about 40-60 percent of the light incident thereon.

Claim 18

The system in accordance with claim 9 wherein said spatial filtering means transmits the light beams of higher order spatial frequencies incident thereon and absorbs at least a portion of the light of zero-order spatial frequency.