Method and apparatus for imaging a target using cloud obscuration prediction and detection

1. A method of imaging targets using an unmanned air vehicle, the method comprising the steps of:

making a determination of cloud obscuration of a target;

selecting an imaging sensor based on the cloud obscuration determination; and

using the selected imaging sensor to produce an image of the target;

wherein the step of making a determination of cloud obscuration of a target comprises the steps of:

firing a laser beam toward an area of interest;

measuring a time for a reflected beam to return to a sensor; and

comparing the measured time to an expected time.

2. The method of claim 1 , wherein the step of making a determination of cloud obscuration of a target further comprises the step of:

detecting clouds based on image content.

3. The method of claim 1 , wherein the step of making a determination of cloud obscuration of a target further comprises the steps of:

taking an image of the target in the area of interest; and

determining an offset between the laser beam and the target in the image.

4. A method of imaging targets using an unmanned air vehicle, the method comprising the steps of:

making a determination of cloud obscuration of a target;

selecting an imaging sensor based on the cloud obscuration determination; and

using the selected imaging sensor to produce an image of the target;

the step of detecting clouds based on image content comprises the steps of:

taking an image of an area of interest;

identifying cloud edges in the image of the area of interest;

summing the number of cloud edges; and

comparing the total number of cloud edges to a predetermined number.

5. The method of claim 4 , wherein the step of identifying cloud edges comprises the step of:

comparing relative velocities of at least two of the edges.

6. The method of claim 4 , wherein the step of making a determination of cloud obscuration of a target further comprises the step of:

detecting clouds based on the relative movement of the clouds.

7. An apparatus for imaging targets from an air vehicle, the apparatus comprising:

a sensing system for determining cloud obscuration of a target;

a processor for using forecasts of precipitation in an area of interest to determine a probability of cloud obscuration along a line of sight between the air vehicle position and a target;

at least two different imaging sensors; and

a controller for selecting one of the target sensors for imaging the target, based on the determined cloud obscuration;

wherein the sensing system comprises:

a laser for producing a beam of light capable of being reflected by clouds; and

a processor for measuring a time for a reflected beam to return to a sensor and for comparing the measured time to an expected time.

8. An apparatus for imaging targets from an air vehicle, the apparatus comprising:

a sensing system for determining cloud obscuration of a target;

a processor for using forecasts of precipitation in an area of interest to determine a probability of cloud obscuration along a line of sight between the air vehicle position and a target;

at least two different imaging sensors; and

a controller for selecting one of the target sensors for imaging the target, based on the determined cloud obscuration;

wherein the sensing system comprises:

a camera for producing images of an area of interest; and

a processor for identifying cloud edges in the images, for summing the cloud edges, and for comparing the total number of cloud edges to a predetermined number.

9. The apparatus of claim 8 , wherein the processor identifies cloud edges by comparing relative velocities of at least two of the edges in different image frames.

10. The apparatus of claim 8 , wherein the sensing system detects clouds based on the relative movement of the clouds.

11. The apparatus of claim 8 , wherein the sensing system further comprises:

a laser for shining a laser beam toward the area of interest; and

the processor measures an offset between the laser beam and the target, and compares the measured offset to a predetermined offset.