Optical straight line detector

Claim 2

Apparatus for determining the presence of straight lines in an object to be viewed comprising a first set of at least two parallel bars forming part of a bar pattern, means for causing the bars to move across an image of the object being viewed; and means for detecting when the bars move across straight lines by generating a low level signal when no straight lines are present in the object viewed and by generating a substantially greater signal when straight lines are viewed.

Claim 3

The apparatus of claim 1 wherein the means for causing the bars to move across the image includes a moving loop of film and wherein the bars are located on said loop of film; said set of bars being composed of a plurality of equally spaced, alternate light and dark areas, and being oriented on the film such that the bars are perpendicular to the direction of travel on the film.

Claim 4

The apparatus of claim 2 including means for determining the presence of straight lines at a plurality of orientations.

Claim 5

The apparatus of claim 3 wherein said last mentioned means comprises a second set of parallel bars; said second set comprising a plurality of equally spaced, alternately light and dark areas and being oriented on the film such that the bars are at an angle other than perpendicular to the direction of travel of the film.

Claim 6

The apparatus of claim 3 wherein said last mentioned meaNs comprises a second set of parallel bars; said second set comprising a plurality of equally spaced and unequally spaced alternate light and dark areas to determine the presence of lines which are not spaced at a distance corresponding to the spatial frequency of said first set of bars.

Claim 7

The apparatus of claim 4 including at least one amplifier for each set of parallel bars.

Claim 8

The apparatus of claim 3 wherein said last mentioned means includes means for changing the orientation of the lines being viewed relative to the bars on the film loop.

Claim 9

The apparatus of claim 7 wherein said orientation changing means includes a means for rotating the image of the object being viewed.

Claim 10

The apparatus of claim 8 wherein the object being viewed is a photograph and wherein the means for rotating the image comprises a means for rotating the photograph.

Claim 11

The apparatus of claim 8 wherein the rotation means comprises a means capable of changing the direction of the light from the object, said means being located between the object and the film loop.

Claim 12

The apparatus of claim 10 wherein the rotation means comprises a K mirror.

Claim 13

The apparatus of claim 7 wherein said orientation changing means comprises a lens of variable magnification.

Claim 14

The apparatus of claim 8 wherein the orientation changing means further includes a lens of variable magnification to detect the presence and spacing of parallel lines.

Claim 15

A straight line detector comprising, in combination; optical means for imaging a scene; a bar pattern disposed in the image plane of said optical means and substantially parallel to a straight line of the scene to be detected appearing in the image plane; radiation sensitive means for receiving radiation from the scene through said bar pattern; and means for moving the bar pattern across the imaged scene to modulate the radiation received by said radiation sensitive means whereby said straight line will generate a signal at the chopping frequency of the bars.

Claim 16

A straight line detector comprising, in combination; optical means for imaging a scene; a bar pattern disposed in the image plane of said optical means and substantially parallel to a straight line of the scene to be detected appearing in the image plane; radiation sensitive means for receiving radiation from the scene through said bar pattern; and means for moving the bar pattern across the imaged scene to modulate the radiation received by said radiation sensitive means whereby said straight line will generate a signal at the chopping frequency of the bars.

Claim 17

The straight line detector of claim 14 wherein said bar pattern comprises alternately opaque and transparent bars.

Claim 18

The straight line detector of claim 15 wherein the chopping frequency is a function of the bar spacing of said pattern and the speed at which the bar pattern is moved across the imaged scene.