Process and apparatus for the separate evaluation of image contents in two coordinate directions of motion

Claim 1

A method of evaluating the image contents of an object in two coordinate directions of motion which comprises the steps of: splitting the image of the object into two separate images having different orthogonal components with a beam splitter; reproducing the said separate images adjacent to one another by rotating the said images by 90° with respect to one another onto a common correlation grid, said grid being periodic in the x and/or y direction; converting the two light fluxes resulting from the impingement of said images on said grid into electric signals; and measuring the said electric signals.

Claim 2

A method of evaluating the image contents of an object in two coordinate directions of motion which comprises the steps of: splitting the image of the object into two separate images having different orthogonal components with a beam splitter; reproducing the said separate images adjacent to one another by rotating the said images by 90° with respect to one another onto a common correlation grid, said grid being periodic in the x and/or y direction; converting the two light fluxes resulting from the impingement of said images on said grid into electric signals; and measuring the said electric signals.

Claim 6

An apparatus for separately measuring the image contents of an object in two coordinate directions of motion, said apparatus comprising: an optical element for receiving the image to be measured; a beam splitting means for orthogonally splitting the image received; a mirror means for reflecting the split images received from the beam splitting surface; and a correction grid arranged to receive said images reflected by said mirror means, said grid being constructed such that it is periodic in at least one orthogonal direction; said beam splitting means and said mirror means formed by a prism combination, said prism combination comprising first, second, third and fourth quadratic prisms; said prisms being arranged such that the base of said first prism is in contact with the base of said second prism to form said mirror means, one cathetus of said third prism being arranged against one cathetus of said first prism and one cathetus of said fourth prism being arranged against one cathetus of said second prism such that a second cathetus of said third prism and a second cathetus of said fourth prism are each located in substantially the same plane and such that said third and fourth prisms are arranged along adjacent sides of said first and second prisms.

Claim 7

An apparatus for separately measuring the image contents of an object in two coordinate directions of motion, said apparatus comprising: an optical element for receiving the image to be measured; a beam splitting means for orthogonally splitting the image received; a mirror means for reflecting the split images received from the beam splitting surface; and a correction grid arranged to receive said images reflected by said mirror means, said grid being constructed such that it is periodic in at least one orthogonal direction; said beam splitting means and said mirror means formed by a prism combination, said prism combination comprising first, second, third and fourth quadratic prisms; said prisms being arranged such that the base of said first prism is in contact with the base of said second prism to form said mirror means, one cathetus of said third prism being arranged against one cathetus of said first prism and one cathetus of said fourth prism being arranged against one cathetus of said second prism such that a second cathetus of said third prism and a second cathetus of said fourth prism are each located in substantially the same plane and such that said third and fourth prisms are arranged along adjacent sides of said first and second prisms.