Abstract A radiometric non-scanning extended-source position-indicating device is provided for determining the position of the edge of an extended source which is independent of the irradiance of the source and relatively independent of any radiation variation of the source. The radiometric device includes an objective lens having a rectangular aperture with radiation detector means optically positioned at the focal plane of the objective lens. The radiation detector means has a rectangular field stop in the focal plane of the objective which determines the rectangular field of view. A reflective vane extending from the detector means along the optical axis toward the objective lens splits the radiation applied from the rectangular objective aperture onto the detector means, producing signal from the detector means which is linearly proportional to the object position in the field of view. The same result is obtained by utilizing a rotating chopper which extends to the optical axis at the proper point for splitting the radiation falling on the detector means.
A non-scanning extended-source position-indicating device for determining the position of an edge of an extended source within a rectangular field of view which is independent of source irradiance and relatively independent of variation of radiation along the extended source comprising, in combination, a. an objective lens having a rectangular aperture and a rectangular field of view, b. radiation detector means optically positioned at the focal plane of said objective lens, c. obstruction means for splitting the radiation from said rectangular field of view falling on said detector means, said obstruction means extending at the optical axis to a point at which a ray of radiation from the lower edge of the aperture crosses the optical axis in reaching the upper edge of said detector means.
Claim 2
Dependent Claim
125 words
A non-scanning extended-source position-indicating device for determining the position of an edge of an extended source within a rectangular field of view which is independent of source irradiance and relatively independent of variation of radiation along the extended source comprising, in combination, a. an objective lens having a rectangular aperture and a rectangular field of view, b. radiation detector means optically positioned at the focal plane of said objective lens, c. obstruction means for splitting the radiation from said rectangular field of view falling on said detector means, said obstruction means extending at the optical axis to a point at which a ray of radiation from the lower edge of the aperture crosses the optical axis in reaching the upper edge of said detector means.
Claim 3
Dependent Claim
40 words
The device set forth in claim 1 wherein said obstruction means comprises a vignetting reflecting vane which is reflective on both sides and extends along the optical axis of said objective lens from said detector means toward said objective lens.
Claim 4
Dependent Claim
20 words
The device set forth in claim 2 wherein said detector means comprises two detectors being separated by said reflecting vane.
Claim 5
Dependent Claim
13 words
The device set forth in claim 3 wherein said two detectors are thermopiles.
Claim 6
Dependent Claim
46 words
The device set forth in claim 1 wherein said obstruction means comprises a radiation chopper which extends to the optical axis at said point where radiation from the lower edge of the aperture crosses the optical axis in reaching the upper edge of said detector means.
Claim 7
Dependent Claim
15 words
The device set forth in claim 5 wherein said detector means comprises a thermistor bolometer.