Abstract

A practical method has been developed for obtaining partial Stokes vector (IQU_) and derivative (IPT_) images of the polarized sky-dome. This method takes advantage of a four-lens stereoscopic camera, a dome mirror, photo CD processing, and commercially available digital image-processing software.

© 1997 Optical Society of America

Full Article  |  PDF Article

References

  • View by:
  • |
  • |
  • |

  1. R. Walraven, “Polarization imagery,” in Optical Polarimetry: Instrumentation and Applications, R. M. A. Azzam, D. L. Coffeen, eds., Proc. SPIE112, 164–167 (1977).
    [CrossRef]
  2. R. Walraven, “Polarization imagery,” Opt. Eng. 20, 14–18 (1981).
    [CrossRef]
  3. D. Clarke, J. F. Grainger, Polarized Light and Optical Measurement (Pergamon, Oxford, 1971).
  4. D. A. Talmadge, P. J. Curran, “Remote sensing using polarized light,” Int. J. Remote Sensing 7, 47–64 (1986).
    [CrossRef]
  5. K. L. Coulson, Solar and Terrestrial Radiation (Academic, New York, 1975).

1986 (1)

D. A. Talmadge, P. J. Curran, “Remote sensing using polarized light,” Int. J. Remote Sensing 7, 47–64 (1986).
[CrossRef]

1981 (1)

R. Walraven, “Polarization imagery,” Opt. Eng. 20, 14–18 (1981).
[CrossRef]

Clarke, D.

D. Clarke, J. F. Grainger, Polarized Light and Optical Measurement (Pergamon, Oxford, 1971).

Coulson, K. L.

K. L. Coulson, Solar and Terrestrial Radiation (Academic, New York, 1975).

Curran, P. J.

D. A. Talmadge, P. J. Curran, “Remote sensing using polarized light,” Int. J. Remote Sensing 7, 47–64 (1986).
[CrossRef]

Grainger, J. F.

D. Clarke, J. F. Grainger, Polarized Light and Optical Measurement (Pergamon, Oxford, 1971).

Talmadge, D. A.

D. A. Talmadge, P. J. Curran, “Remote sensing using polarized light,” Int. J. Remote Sensing 7, 47–64 (1986).
[CrossRef]

Walraven, R.

R. Walraven, “Polarization imagery,” Opt. Eng. 20, 14–18 (1981).
[CrossRef]

R. Walraven, “Polarization imagery,” in Optical Polarimetry: Instrumentation and Applications, R. M. A. Azzam, D. L. Coffeen, eds., Proc. SPIE112, 164–167 (1977).
[CrossRef]

Int. J. Remote Sensing (1)

D. A. Talmadge, P. J. Curran, “Remote sensing using polarized light,” Int. J. Remote Sensing 7, 47–64 (1986).
[CrossRef]

Opt. Eng. (1)

R. Walraven, “Polarization imagery,” Opt. Eng. 20, 14–18 (1981).
[CrossRef]

Other (3)

D. Clarke, J. F. Grainger, Polarized Light and Optical Measurement (Pergamon, Oxford, 1971).

K. L. Coulson, Solar and Terrestrial Radiation (Academic, New York, 1975).

R. Walraven, “Polarization imagery,” in Optical Polarimetry: Instrumentation and Applications, R. M. A. Azzam, D. L. Coffeen, eds., Proc. SPIE112, 164–167 (1977).
[CrossRef]

Cited By

OSA participates in CrossRef's Cited-By Linking service. Citing articles from OSA journals and other participating publishers are listed here.

Alert me when this article is cited.


Figures (8)

Fig. 1
Fig. 1

Imaging polarimeter.

Fig. 2
Fig. 2

In-field setup.

Fig. 3
Fig. 3

Image pair at 90° and 0°.

Fig. 4
Fig. 4

Image pair at 135° and 45°.

Fig. 5
Fig. 5

Solar elevation measurements.

Fig. 6
Fig. 6

Unpolarized irradiance (I), percent polarization (P), and orientation angle (T) parameter images of the mirror-reflected sky-dome over Syracuse N.Y. on 7 November 1994 at solar elevations of 26.9°, 23.0°, 16.3°, and 7.9°, respectively. A static group of boxes visible in the upper edge of the imaged horizon provides an indication of the tracking of the polarimeter reference plane with the changing Sun azimuth (and hence the principal plane azimuth also).

Fig. 7
Fig. 7

Absolute value of T parameter images, histograms of T parameter images, and the absolute value of the same T parameter images after an azimuthal bias of -1.4°, -5.9°, -5.6°, and -6.2°, respectively, applied to each image pixel by way of arctan [tan (T + bias)]. Note the restoration of bilateral symmetry relative to the principal plane. The histogram spikes at 22.5° intervals are artifacts created by the presence of saturated and near-saturated pixel irradiances in the two orthogonally polarized image pairs.

Fig. 8
Fig. 8

D parameter images and their surface plots. The average DN and standard deviation for each image is listed on the right. For reference, the pixels in the vicinity of the Sun have D values of zero. Note that the largest deviations correspond to misregistrations of the polarimeter supports from parallax effects created by the finite separation of the four apertures. Note also that the full range of D values is from -510 to +510 DN’s.

Equations (7)

Equations on this page are rendered with MathJax. Learn more.

Simage=IimageQimageUimageVimage=polarizerθrotαmirrorφ×rotβIskyQskyUskyVsky,
I0°=I+Q/2,I45°=I+U/2,I90°=I-Q/2,I135°=I-U/2.
IQUV=I0°+I90°=I45°+I135°=I0°+I45°+I90°+I135°/2I0°-I90°I45°-I135°0.
IQUV=IP cos2Ecos2TP cos2Esin2TP sin2E=IP cos2TP sin2T0, IPTE=IQ2+U2+V2/Itan-1U/Q/2sin-1V/Q2+U2+V2/2=IQ2+U2/Itan-1U/Q/2 0.
D=I-I=I0°+I90°-I45°+I135°=0 if perfectly calibrated.
γcal logDNcal-biascal]=D=γuncal logDNuncal-biasuncal,
DNcal=10 γuncal logDNuncal+biascal-biasuncal/γcal.

Metrics