Differential holography

Claim 1

A dynamic method of holographic inspection by creating a hologram of an inspected object, carried out with inspection using paired exposures including the steps of subjecting an object to intermittent stressing, detecting via waves constructed from the finished hologram or holograms at least one of the groups of fine and/or gross alterations in individual structures and regions of said object response to application of said intermittent stressing, creating a hologram by intermittent exposures of a holographic emulsion or other sensor to reference radiation and the analytical radiation which is passed through or reflected from said object to provide a hologram selected from the group consisting of a positively unbalanced hologram formed by a first exposure of a holographic emulsion, or other sensor, to the interference pattern of a reference wave and a first compared object wave, the integrated intensity of exposure to the reference wave being (1+ε) units, and by a second exposure of said holographic emulsion, or other sensor, to the interference pattern from the reference wave and a second compared object wave, with the integrated intensity of exposure to the reference wave being (1-ε) units and the optical path of the reference wave during the second exposure differing by one-half wavelength from the optical path of the reference wave during the first exposure, or a negatively unbalanced hologram formed by a first exposure of a holographic emulsion, or other sensor, to the interference pattern of a reference wave and a first compared object wave, with the integrated intensity of exposure to the reference wave being (1-ε) units, and by a second exposure of said holographic emulsion, or other sensor, to the interference pattern from the reference wave and a second compared object wave, with the integrated intensity of exposure to the reference wave being (1+ε) units and the optical path of the reference wave during the second exposure differing by one-half wavelength from the optical path of the reference wave during the first exposure, or a phase-advanced hologram formed by a first exposure of a holographic emulsion, or other sensor, to the interference pattern of a reference wave and a first compared object wave and by a second exposure of said holographic emulsion to an interference pattern from the reference wave and a second compared object wave, in each exposure the integrated intensity of exposure to the reference wave being one unit, and the optical path of the reference wave during the second exposure differing by (1/2+q) wavelength from the optical path of the reference wave during the first exposure, or, a phase-retarded hologram formed by a first exposure of a holgoraphic emulsion, or other sensor, to the interference pattern from a reference wave and a first compared object wave and by a second exposure of said holographic emulsion, or other sensor, to the interference pattern from the reference wave and a second compared object wave, in each exposure the integrated intensity of exposure to the reference wave being one unit and the optical path of the reference wave during the second exposure differing by (1/2-q) wavelength from the optical path of the reference wave during the first exposure, wherein ε is substantially greater than 0 and less than or equal to 0.5 and wherein q is substantially greater than 0 and less than or equal to 0.25.

Claim 6

An apparatus for dynamic holographic inspection comprising, in combination, at least one coherent radiation source directed toward an object which is subjected to inspection, means in association with said radiation source for carrying out the inspection by creating a hologram of said object using paired exposures including means for subjecting said object to intermittent stressing during the inspection, and means for detecting, via waves constructed from the finished hologram or holograms, at least one of the group fine and/or gross alterations in individual structures and regions of said object responsive to application of said intermittent stressing, said hologram or holograms being created by intermittent exposure of a holographic emulsion or other sensor to reference radiation and the analytical radiation which is passed through or reflected from said object to provide a hologram selected from the group consisting of (a) a positively unbalanced hologram formed by a first exposure of holographic emulsion, or other sensor, to the interference pattern of a referenoe wave and a first compared object wave, the integrated intensity of exposure to the reference wave being (1+ε) units, and by a second exposure of said holographic emulsion, or other sensor, to the interference pattern of the reference wave and a second compared object wave, with the integrated intensity of exposure to the reference wave being (1-ε) units and the optical path of the reference wave during the second exposure differing by one-half wavelength from the optical path of the reference wave during the first exposure; or (b) a negatively unbalanced hologram formed by a first exposure of a holographic emulsion, or other sensor, to the interference pattern of a reference wave and a first compared object wave, with the integrated intensity of exposure to the reference wave being (1-ε) units, and by a second exposure of said holographic emulsion, or other sensor, to the interference pattern of the reference wave and the second compared object wave, with the integrated intensity of exposure to the reference wave being (1+ε) units, and the optical path of the reference wave during the second exposure differing by one-half wavelength from the optical path of the reference wave during the first exposure, or (c) a phase-advanced hologram formed by a first exposure of a holographic emulsion, or other sensor, to the interference pattern of a reference wave and a first compared object wave and by a second exposure of said holographic emulsion to the interference pattern of the reference wave and a second compared object wave, in each exposure the integrated intensity of exposure to the reference wave being one unit, and the optical path of the reference wave during the second exposure differing by (1/2+q) wavelength from the optical path of the reference wave during the first exposure or (d) a phase retarded hologram formed by a first exposure of the holographic emulsion, or other sensor, to the interference pattern of a reference wave and a first compared object wave and by a second exposure of said holographic emulsion, or other sensor, to the interference pattern of the reference wave and a second compared object wave, in each exposure the integrated intensity of exposure to the reference wave being one unit and the optical path of the reference wave during the second exposure differing by (1/2-q) wavelength from the optical path of the reference wave during the first exposure, wherein ε is substantially greater than 0 and less than or equal to 0.5 and wherein q is substantially greater than 0 and less than or equal to 0.25.

Claim 7

An apparatus for dynamic holographic inspection comprising, in combination, at least one coherent radiation source directed toward an object which is subjected to inspection, means in association with said radiation source for carrying out the inspection by creating a hologram of said object using paired exposures including means for subjecting said object to intermittent stressing during the inspection, and means for detecting, via waves constructed from the finished hologram or holograms, at least one of the group fine and/or gross alterations in individual structures and regions of said object responsive to application of said intermittent stressing, said hologram or holograms being created by intermittent exposure of a holographic emulsion or other sensor to reference radiation and the analytical radiation which is passed through or reflected from said object to provide a hologram selected from the group consisting of (a) a positively unbalanced hologram formed by a first exposure of holographic emulsion, or other sensor, to the interference pattern of a referenoe wave and a first compared object wave, the integrated intensity of exposure to the reference wave being (1+ε) units, and by a second exposure of said holographic emulsion, or other sensor, to the interference pattern of the reference wave and a second compared object wave, with the integrated intensity of exposure to the reference wave being (1-ε) units and the optical path of the reference wave during the second exposure differing by one-half wavelength from the optical path of the reference wave during the first exposure; or (b) a negatively unbalanced hologram formed by a first exposure of a holographic emulsion, or other sensor, to the interference pattern of a reference wave and a first compared object wave, with the integrated intensity of exposure to the reference wave being (1-ε) units, and by a second exposure of said holographic emulsion, or other sensor, to the interference pattern of the reference wave and the second compared object wave, with the integrated intensity of exposure to the reference wave being (1+ε) units, and the optical path of the reference wave during the second exposure differing by one-half wavelength from the optical path of the reference wave during the first exposure, or (c) a phase-advanced hologram formed by a first exposure of a holographic emulsion, or other sensor, to the interference pattern of a reference wave and a first compared object wave and by a second exposure of said holographic emulsion to the interference pattern of the reference wave and a second compared object wave, in each exposure the integrated intensity of exposure to the reference wave being one unit, and the optical path of the reference wave during the second exposure differing by (1/2+q) wavelength from the optical path of the reference wave during the first exposure or (d) a phase retarded hologram formed by a first exposure of the holographic emulsion, or other sensor, to the interference pattern of a reference wave and a first compared object wave and by a second exposure of said holographic emulsion, or other sensor, to the interference pattern of the reference wave and a second compared object wave, in each exposure the integrated intensity of exposure to the reference wave being one unit and the optical path of the reference wave during the second exposure differing by (1/2-q) wavelength from the optical path of the reference wave during the first exposure, wherein ε is substantially greater than 0 and less than or equal to 0.5 and wherein q is substantially greater than 0 and less than or equal to 0.25.