Polorization viewer

• US 5,557,324 A
• Filed: 10/29/1992
• Issued: 09/17/1996
• Est. Priority Date: 10/29/1992
• Status: Expired

• Current Assignee: Johns Hopkins University
• Original Assignee: Johns Hopkins University
• Inventors: Wolff, Lawrence B.
• Primary Examiner(s): Garber, Wendy
• Assistant Examiner(s): Ho, Tuan V.
• Application Number:
  US07/968,175
• Time in Patent Office: 1,419 Days
• Field of Search: 348/207, 348/335, 348/336, 348/337, 348/338, 348/54, 348/57, 348/58, 348/49, 348/46, 359/247, 359/495, 359/63, 359/65
• US Class Current: 345/207
• CPC Class Codes: G01J 4/00 Measuring polarisation of light
• CPC Class Codes: G01J 4/04 Polarimeters using electric detection means G01J4/02 takes precedence

Abstract

A polarization viewer comprising a mechanism for forming a broadview image having a spectral width greater than 2 angstroms and 0.50° based on polarization information of a scene. The polarization viewer is also comprised of a mechanism for providing polarization information to the forming mechanism. The providing mechanism is in communication with the forming mechanism. In a first embodiment, the providing mechanism includes a camera mechanism in communication with the forming mechanism. The camera mechanism includes a fixed polarizer analyzer disposed such that electromagnetic radiation entering the camera mechanism passes through the polarizer analyzer. The providing mechanism can also include a mechanism for steering a polarization plane of the radiation. The steering mechanism is disposed such that radiation passing through the polarizer analyzer first passes through the steering mechanism. The steering mechanism preferably includes a first twist crystal and at least a second twist crystal aligned with the first twist crystal such that radiation passing through the first crystal then passes through the second crystal. Each crystal has a first state and a second state. The first state does not effect the polarization plane of the radiation as the radiation passes through the crystal. The second state rotates the polarization plane of the radiation as the radiation passes through the crystal.

Claims

1. A polarization viewer comprising:

a first CCD chip which produces a first signal, said first signal corresponding to a measurement of a first polarization component based on electromagnetic radiation the first CCD chip receives;

a first beamsplitter disposed such that radiation reflected by the first beamsplitter is received by the first CCD chip;

a second CCD chip which produces a second signal corresponding to a measurement of a second polarization component based on electromagnetic radiation the second CCD chip receives which is transmitted by the beamsplitter, said second CCD chip disposed such that the second CCD chip receives radiation transmitted by the beamsplitter;

a mechanism for creating polarization information corresponding to a polarization orientation different than that corresponding with the first or second CCD chip; and

a mechanism for forming a polarization image based on the first and second signals and the creating mechanism, said forming mechanism in communication with the first and second CCD chips and the generating mechanism.

2. A viewer as described in claim 1 wherein the creating mechanism includes a twist crystal disposed adjacent to the first beamsplitter such that radiation received by the first beamsplitter first passes through the twist crystal.

3. A viewer as described in claim 2 wherein the first beamsplitter is oriented at a 45°

angle relative to radiation incident to the first beam splitter.

4. A viewer as described in claim 3 wherein the twist crystal has a first state and a second state, said first state uneffecting the polarization plane of the radiation as radiation passes through the twist crystal, said second state rotating the polarization plane of the radiation as the radiation passes through the twist crystal.

5. A viewer as described in claim 4 including a driver in communication with the crystal which controls the state of the crystal.

6. A viewer as described in claim 5 wherein when the crystal is in the second state, the polarization plane of radiation passes therethrough is rotated 45°

.

7. A viewer as described in claim 6 wherein the first CCD chip receives radiation reflected 90°

by the first beamsplitter.

8. A polarization viewer comprising:

a first CCD chip which produces a first signal, said first signal corresponding to a measurement of a first polarization component based on electromagnetic radiation the first CCD chip receives;

a first beamsplitter disposed such that radiation reflected by the first beamsplitter is received by the first CCD chip;

a second CCD chip which produces a second signal corresponding to a measurement of a second polarization component based on electromagnetic radiation the second CCD chip receives which is transmitted by the beamsplitter, said second CCD chip disposed such that the second CCD chip receives radiation transmitted by the beamsplitter; and

a mechanism for forming a polarization image based on the first and second signals, said forming mechanism in communication with the first and second CCD chips.

9. A viewer as described in claim 8 wherein the first beamsplitter is oriented at a 45°

angle relative to radiation incident to the first beam splitter.

10. A polarization viewer comprising:

a first CCD chip which produces a first signal, said first signal corresponding to a measurement of a first polarization component based on electromagnetic radiation receives;

a first beamsplitter disposed such that radiation reflected by the first beamsplitter is received by the first CCD chip;

a second CCD chip which produces a second signal corresponding to a measurement of a second polarization component based on electromagnetic radiation receives which is transmitted by the beamsplitter, said second CCD chip disposed such that receives radiation transmitted by the beamsplitter;

means for creating polarization information corresponding to a polarization orientation different than that corresponding with the first or second CCD chip; and

means for forming a polarization image based on the first and second signals and the creating means, said forming means in communication with the first and second CCD chips and the generating means.

11. A polarization viewer comprising:

a first CCD chip which produces a first signal, said first signal corresponding to a measurement of a first polarization component based on electromagnetic radiation receives;

a first beamsplitter disposed such that radiation reflected by the first beamsplitter is received by the first CCD chip;

a second CCD chip which produces a second signal corresponding to a measurement of a second polarization component based on electromagnetic radiation receives which is transmitted by the beamsplitter, said second CCD chip disposed such that receives radiation transmitted by the beamsplitter; and

means for forming a polarization image based on the first and second signals, said forming means in communication with the first and second CCD chips.