Real time interferometry contour mapping system

Claim 2

Apparatus for measuring small dimension surface height contours of an object by real time hologram interferometry Comprising: means for illuminating a standard reference surface to form a first scattered and reflected object beam and for illuminating the object whose surface height contours are to be measured to form a second scattered and reflected object beam; means for generating from said illuminating means, a reference light beam; a television camera tube for receiving a visual input and providing an electrical output; means for combining said first object beam scattered and reflected from the standard surface with said reference light beam to form a first interference pattern which is received by said television camera tube as a visual input and for combining said second object beam scattered and reflected from the object surface with said reference light beam to form a second interference pattern said combining means positioned for projecting the first and second interference patterns at the visual input of said television camera tube for generating first and second electrical output corresponding to the first and second interference patterns respectively; means for storing the first electrical output of said television camera tube corresponding to said first interference pattern; and means for combining the second electrical output of said television camera tube corresponding to said second interference pattern with the stored electrical output of said television camera tube corresponding to said first interference pattern to form a signal containing surface position height information about the object surface relative to the standard surface.

Claim 3

Apparatus as described in claim 1 including restricting means for restricting the spatial frequency spectra of said first and second interference patterns to that of the television camera tube.

Claim 4

Apparatus as described in claim 2 in which said restricting means comprises a light frequency shifter inserted in the path of said reference light beam to provide a cyclical temporal offset of said reference light beam.

Claim 5

Apparatus as described in claim 1 comprising angular offset of said reference light beam with respect to the axis of said scattered and reflected object beam to allow the use of storage camera tubes.

Claim 6

Apparatus as described in claim 3 including a filter for removing unwanted components from the first and second electrical outputs of said television camera tube to form first and second filtered electrical outputs.

Claim 7

Apparatus as described in claim 3 in which said means for utilizing said signal containing position height information comprises a limiter for removing first pattern information.

Claim 8

Apparatus as described in claim 5 including envelope detecting means for envelope detecting said signal containing position deformation information.

Claim 9

Apparatus as described in claim 5 including a cathode ray tube for displaying the output of said envelope detecting means.

Claim 10

Apparatus as described in claim 5 including means for separating said first and second filtered electrical outputs into real and imaginary parts.

Claim 11

Apparatus ad described in claim 5 including means for synchronizing the second electrical output of said television camera tube to the stored first electrical output of said television camera tube.

Claim 12

Apparatus as described in claim 9 including means for combining the real and imaginary parts of said first and second filtered electrical outputs to form said signal containing position information.

Claim 13

Apparatus as set forth in claim 1 wherein said standard reference surface is a plane surface.

Claim 14

Apparatus as set forth in claim 1 wherein said standard reference surface comprises a smooth regular surface.

Claim 15

Apparatus for measuring small dimension height variations in an object surface by real time hologram interferometry comprising: means for illuminating a standard reference surface to form a first scattered and reflected object beam and for illuminating the object surface whose heights of variations are to be measured to form a second sCattered and reflected object beam; means for generating from said illuminating means a reference light beam; a storage television camera tube for receiving a visual input and for converting the visual input information to an electrical output; means for combining said first object beam scattered and reflected from the standard surface with said reference light beam to form a first interference pattern which is received by said tube and for combining said second object beam scattered and reflected from the object surface with said reference light beam to form a second interference pattern which is received by said tube, said reference light beam disposed at an angle with respect to said first and second scattered and reflected object beams in order to eliminate undesired patterns by making their spatial frequencies beyond the capabilities of said storage television camera tube, said storage television camera tube providing temporary storage for superimposing the first and second interference pattersn at the visual input of the storage television camera tube; means for scanning said storage television camera tube to produce an electrical output signal; and inspecting means for inspecting said output signal to derive surface position height information about the object surface relative to the standard surface.

Claim 16

Apparatus for measuring small dimension height variations in an object surface by real time hologram interferometry comprising: means for illuminating a standard reference surface to form a first scattered and reflected object beam and for illuminating the object surface whose heights of variations are to be measured to form a second sCattered and reflected object beam; means for generating from said illuminating means a reference light beam; a storage television camera tube for receiving a visual input and for converting the visual input information to an electrical output; means for combining said first object beam scattered and reflected from the standard surface with said reference light beam to form a first interference pattern which is received by said tube and for combining said second object beam scattered and reflected from the object surface with said reference light beam to form a second interference pattern which is received by said tube, said reference light beam disposed at an angle with respect to said first and second scattered and reflected object beams in order to eliminate undesired patterns by making their spatial frequencies beyond the capabilities of said storage television camera tube, said storage television camera tube providing temporary storage for superimposing the first and second interference pattersn at the visual input of the storage television camera tube; means for scanning said storage television camera tube to produce an electrical output signal; and inspecting means for inspecting said output signal to derive surface position height information about the object surface relative to the standard surface.

Claim 17

Apparatus as described in claim 14 in which said inspecting means comprises a cathode ray tube adapted to be viewed by an operator.

Claim 18

Apparatus as set forth in claim 14 wherein said standard surface is a plane surface.

Claim 19

Apparatus for generating small dimension height contours for an object surface by real time hologram interferometry comprising: means for illuminating a standard reference plane surface to form a first scattered and reflected object beam and for illuminating the object surface whose height contours are to be generated to form a second scattered and reflected object beam; means for generating from said illuminating means a reference light beam; a storage television camera tube for receiving a visual input and converting the visual input information to an electrical output; means for combining said first object beam scattered and reflected from the standard plane with said reference light beam to form a first interference pattern and for combining said second object beam scattered and reflected from the object surface with said reference light beam to form a second interference pattern, said reference light beam disposed at an angle with respect to said first and second scattered and reflected object beams in order to separate the interference information from that of the image said combining means positioned for projecting said first and second interference patterns at the visual input of said storage television camera tube; means for storing a first electrical output from the storage television camera tube corresponding to the first interference pattern projected at at storage television camera tube input; and means for combining a second electrical output from the storage television camera tube corresponding to the second interference pattern projected ac the storage television camera tube input to form a signal containing object surface contour information.

Claim 20

Apparatus for generating small dimension height contours for an object surface by real time hologram interferometry comprising: means for illuminating a standard reference plane surface to form a first scattered and reflected object beam and for illuminating the object surface whose height contours are to be generated to form a second scattered and reflected object beam; means for generating from said illuminating means a reference light beam; a storage television camera tube for receiving a visual input and converting the visual input information to an electrical output; means for combining said first object beam scattered and reflected from the standard plane with said reference light beam to form a first interference pattern and for combining said second object beam scattered and reflected from the object surface with said reference light beam to form a second interference pattern, said reference light beam disposed at an angle with respect to said first and second scattered and reflected object beams in order to separate the interference information from that of the image said combining means positioned for projecting said first and second interference patterns at the visual input of said storage television camera tube; means for storing a first electrical output from the storage television camera tube corresponding to the first interference pattern projected at at storage television camera tube input; and means for combining a second electrical output from the storage television camera tube corresponding to the second interference pattern projected ac the storage television camera tube input to form a signal containing object surface contour information.

Claim 21

Apparatus as described in claim 17 in which said means for combining said first and said second electrical outputs comprises a subtracter having an output.

Claim 22

Apparatus as described in claim 18 including an envelope detector for detecting said envelope of said subtracter to form said signal containing position deformation information.

Claim 23

Apparatus as described in claim 1 in which said television camera tube is a storage tube and in which said means for combining the second electrical output of said television camera tube corresponding to said second interference pattern with the stored first electrical output of said television camera tube corresponding to said first interference pattern comprises a subtracter whiCh produces said signal containing position information only when there is position deformation in the object between said first and said second interference pattern.

Claim 24

Apparatus for measuring small dimensional changes in an object by real time hologram interferometry comprising: a television camera tube spaced from the object along an optical axis, said camera tube adapted for receiving a visual input and generating an electrical output; means for illuminating a standard reference surface with first and second plane waves incident on the standard surface at angles theta 1 and theta 2 respectively, said angles measured with respect to said optical axis of said television camera tube, whereby said first and second plane waves form a first interference pattern on the standard surface, and for illuminating the object with first and second plane waves incident on the object at angles theta 1 and theta 2 respectively said angles measured with respect to the optical axis of said television camera tube whereby said first and second plane waves form a second interference pattern on said object; means for imaging the first and second interference patterns on the visual input of said television camera tube to form first and second electrical outputs; storage means for storing said first electrical output; combining means for combining said second electrical output with said first electrical output from said storage means to form a combined output; and detecting means for detecting said combined output to form a detected output.

Claim 25

Apparatus for measuring small dimensional changes in an object by real time hologram interferometry comprising: a television camera tube spaced from the object along an optical axis, said camera tube adapted for receiving a visual input and generating an electrical output; means for illuminating a standard reference surface with first and second plane waves incident on the standard surface at angles theta 1 and theta 2 respectively, said angles measured with respect to said optical axis of said television camera tube, whereby said first and second plane waves form a first interference pattern on the standard surface, and for illuminating the object with first and second plane waves incident on the object at angles theta 1 and theta 2 respectively said angles measured with respect to the optical axis of said television camera tube whereby said first and second plane waves form a second interference pattern on said object; means for imaging the first and second interference patterns on the visual input of said television camera tube to form first and second electrical outputs; storage means for storing said first electrical output; combining means for combining said second electrical output with said first electrical output from said storage means to form a combined output; and detecting means for detecting said combined output to form a detected output.

Claim 26

Apparatus according to claim 21 where said television camera is a storage television camera.

Claim 27

Apparatus according to claim 21 in which said combining means comprises a subtracter for subtracting said second electrical output from said first electrical output.

Claim 28

Apparatus according to claim 21 including a light frequency shifter situated in the path of said second plane wave to provide a cyclical temporal offset of said reference light beam.

Claim 29

Apparatus as described in claim 24 including a filter for removing unwanted components from the first and second electrical outputs of said television camera to form first and second filtered electrical outputs.

Claim 30

Apparatus as described in claim 25 including envelope detecting means for envelope detecting said signal containing position deformation information.

Claim 31

Apparatus as set forth in claim 21 wherein said standard surface comprises a plane surface.

Claim 32

Apparatus as set forth in claim 21 wherein said standard surface comprises a smooth regular surface.

Claim 35

The method as described in claIm 29 including the step of restricting the spatial frequency spectra of said first and second interference patterns to that of the television camera tube.

Claim 36

The method as described in claim 30 in which said step of restricting comprises cyclically temporally offsetting said reference light beam.

Claim 37

The method as described in claim 29 comprising the step of angularly offsetting said reference light beam with respect to the axis of said scattered and reflected object beams to allow the use of storage camera tubes.

Claim 38

A method as described in claim 31 including the step of filtering unwanted components from the first and second electrical outputs of said television camera tube to form first and second filtered electrical outputs.

Claim 39

The method as described in claim 29 including the step of envelope detecting said signal containing position height information.

Claim 40

The method as described in claim 34 including the step of displaying the result of said envelope detecting.

Claim 41

The method as described in claim 33 including the step of separating said first and second filtered electrical outputs into real and imaginary parts.

Claim 42

The method as described in claim 33 including the step of synchronizing the second electrical output of said television camera tube to the stored first electrical output of said television camera tube.

Claim 43

The method described in claim 36 including the step of combining the real and imaginary parts of said first and second filtered electrical outputs to form said signal containing position information.

Claim 48

A method according to claim 40 including the step of cyclically temporally offsetting said reference light beam.

Claim 49

A method as described in claim 41 including the step of filtering unwanted components from the first and second electrical outputs of said television camera to form first and second filtered electrical outputs.

Claim 50

A method as described in claim 42 including the step of envelope detecting said combined signal.