Radiometric calibration system
AssigneeEastman Kodak Company
InventorsThomas Willliam Dey, Kenneth L. Mason
Life of this patent
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Abstract
A radiometric calibration system is proposed to calibrate the sensor array of a space born optical imaging system. The calibration system comprises an occulting plate with an occulting convolution aperture which executes a relative lateral motion with respect to an image of the sun, to effect a deterministic and continuously varying calibration flux level to the sensor array. The shape, size orientation and apodization of the aperture control the functional form of the temporal irradiance function reaching the sensor being calibrated. Continuous calibration functions covering a range from a minimum to a maximum desired flux level are readily achievable.
Claims7
Apparatus of the type employing the sun as a deterministic source of radiation for radiometrically calibrating a photodetector array located in the image plane of an imaging system in space, the imaging system defining a pupil, comprising:
- a. calibration optics for forming an image of the sun at the pupil of the imaging system such that the radiometric flux from the sun fills the image plane of the imaging system without vignetting;
- b. an occulting plate defining a convolution aperture located at the focal plane of the calibration optics;
- and
- c. means for providing relative movement between the image of the sun and the occulting plate aperture to continuously modulate the radiometric flux passing the pupil.
Dependencies are inferred from the claim text.