US 6,329,660 B1 · Method of deriving sunlight induced fluorescence from radiance measurements and devices for executing the method

Abstract

To derive sunlight induced fluorescence from radiance measurements, a first radiance measurement is taken inside an atmospheric absorption band, and an additional radiance measurement is taken outside of the atmospheric absorption band. Images of sunlight-induced fluorescence are obtained with the aid of a camera. Air- or spaceborne spectrometers and image points on non-fluorescent objects are used to determine the radiance conditions on the ground and the influence of the atmosphere.

Claims14

Dependent claims

A method of deriving sunlight induced fluorescence from radiance measurements, comprising:

taking a first radiance measurement inside an atmospheric absorption band;
taking a second radiance measurement outside of the atmospheric absorption band;
deriving the sunlight induced fluorescence from image data obtained with the aid of air- or spaceborne spectrometers, and
using image points of non-fluorescent objects to determine radiance conditions on the ground and an influence of the atmosphere.

1 more element

A device for deriving sunlight induced fluorescence from radiance measurements by a method that includes:

taking a first radiance measurement inside an atmospheric absorption band;
and taking a second radiance measurement outside of the atmospheric absorption band, and for detecting sunlight induced fluorescence from a measured object (2) at a distance of several meters from the device, the device comprising:
(a) a first detection unit (3) recording light emitted by the measured object (2) when the measured object is illuminated by the sun, the first detection unit comprising:
a first optical waveguide (31) having a first light receiving end and comprising a first plurality of individual multimode fibers, the first plurality of fibers being divided fork-like, adjacent a light-emitting end, into two first sections of approximately equal size, and
respective first detectors (34, 35) disposed adjacent the two first sections, the first detectors including respective first interference band-pass filters (32, 33) disposed between the two first sections of the first optical waveguide (31) and the first detectors (34, 35);
and
(b) a second detection unit (4) receiving irradiated sunlight, the second detection unit comprising:
a second optical waveguide (41) having a second light-receiving end and comprising a second plurality of individual multimode fibers, the second plurality of fibers being divided fork-like, adjacent a light-emitting end, into two second sections of approximately equal size,
respective second detectors (44, 45) disposed adjacent the two second sections, including respective second interference band-pass filters (42, 43) disposed between the two second sections of the second optical waveguide (41) and the second detectors (44, 45), and
a diffusor (46) disposed adjacent the light-receiving end of the second optical waveguide (41) and orientable toward the sun.

7 more elements

A device for deriving sunlight induced fluorescence from radiance measurements by a method that includes:

taking a first radiance measurement inside an atmospheric absorption band;
and taking a second radiance measurement outside of the atmospheric absorption band, and for detecting sunlight induced fluorescence from a measured object (2), the device comprising:
(a) a pair of detection units (3, 4), each of the detection units comprising:
an optical waveguide (31, 41) comprising a plurality of individual multimode fibers extending between a bundled end intended to receive light and a divided end intended to emit light, the plurality of fibers being fork-like divided into two sections at the divided end;
a respective detector (34,35;
44,45) disposed adjacent each of the two sections of the divided end;
a first interference band-pass filter (32,42) disposed between a first one of the sections and the respective detector adjacent thereto;
and
a second interference band-pass filter (33,43) disposed between a second one of the sections and the respective detector adjacent thereto;
(b) wherein in each of the two detection units the first interference band-pass filter thereof includes a first passband centered on a first wavelength, and wherein in each of the two detection units the second interference band-pass filter thereof includes a second passband centered on a second wavelength different from the first wavelength;
whereby,
a first one of the detection units receives at the bundled end thereof light emitted by the measured object (2) when the measured object is illuminated by the sun (1),
a second one of the detection units receives at the bundled end thereof radiated sunlight, and
the sunlight induced fluorescence is detectable by a comparison of signals from the detectors.

11 more elements

Dependencies are inferred from the claim text.

Abstract

Claims14

Dependent claims

A method of deriving sunlight induced fluorescence from radiance measurements, comprising:

taking a first radiance measurement inside an atmospheric absorption band;
taking a second radiance measurement outside of the atmospheric absorption band;
deriving the sunlight induced fluorescence from image data obtained with the aid of air- or spaceborne spectrometers, and
using image points of non-fluorescent objects to determine radiance conditions on the ground and an influence of the atmosphere.

1 more element

A device for deriving sunlight induced fluorescence from radiance measurements by a method that includes:

taking a first radiance measurement inside an atmospheric absorption band;
and taking a second radiance measurement outside of the atmospheric absorption band, and for detecting sunlight induced fluorescence from a measured object (2) at a distance of several meters from the device, the device comprising:
(a) a first detection unit (3) recording light emitted by the measured object (2) when the measured object is illuminated by the sun, the first detection unit comprising:
a first optical waveguide (31) having a first light receiving end and comprising a first plurality of individual multimode fibers, the first plurality of fibers being divided fork-like, adjacent a light-emitting end, into two first sections of approximately equal size, and
respective first detectors (34, 35) disposed adjacent the two first sections, the first detectors including respective first interference band-pass filters (32, 33) disposed between the two first sections of the first optical waveguide (31) and the first detectors (34, 35);
and
(b) a second detection unit (4) receiving irradiated sunlight, the second detection unit comprising:
a second optical waveguide (41) having a second light-receiving end and comprising a second plurality of individual multimode fibers, the second plurality of fibers being divided fork-like, adjacent a light-emitting end, into two second sections of approximately equal size,
respective second detectors (44, 45) disposed adjacent the two second sections, including respective second interference band-pass filters (42, 43) disposed between the two second sections of the second optical waveguide (41) and the second detectors (44, 45), and
a diffusor (46) disposed adjacent the light-receiving end of the second optical waveguide (41) and orientable toward the sun.

7 more elements

A device for deriving sunlight induced fluorescence from radiance measurements by a method that includes:

taking a first radiance measurement inside an atmospheric absorption band;
and taking a second radiance measurement outside of the atmospheric absorption band, and for detecting sunlight induced fluorescence from a measured object (2), the device comprising:
(a) a pair of detection units (3, 4), each of the detection units comprising:
an optical waveguide (31, 41) comprising a plurality of individual multimode fibers extending between a bundled end intended to receive light and a divided end intended to emit light, the plurality of fibers being fork-like divided into two sections at the divided end;
a respective detector (34,35;
44,45) disposed adjacent each of the two sections of the divided end;
a first interference band-pass filter (32,42) disposed between a first one of the sections and the respective detector adjacent thereto;
and
a second interference band-pass filter (33,43) disposed between a second one of the sections and the respective detector adjacent thereto;
(b) wherein in each of the two detection units the first interference band-pass filter thereof includes a first passband centered on a first wavelength, and wherein in each of the two detection units the second interference band-pass filter thereof includes a second passband centered on a second wavelength different from the first wavelength;
whereby,
a first one of the detection units receives at the bundled end thereof light emitted by the measured object (2) when the measured object is illuminated by the sun (1),
a second one of the detection units receives at the bundled end thereof radiated sunlight, and
the sunlight induced fluorescence is detectable by a comparison of signals from the detectors.

11 more elements

Dependencies are inferred from the claim text.

Method of deriving sunlight induced fluorescence from radiance measurements and devices for executing the method

Life of this patent

Abstract

Claims14

Method of deriving sunlight induced fluorescence from radiance measurements and devices for executing the method

Life of this patent

Abstract

Claims14