Dual-Swath Imaging System

• US 20100328499A1
• Filed: 06/26/2009
• Published: 12/30/2010
• Est. Priority Date: 06/26/2009
• Status: Active Grant

• Current Assignee: KEYW Corporation
• Original Assignee: Flight Landata, Inc. (The Keyw Corporation)
• Inventors: SUN, XIUHONG
• Granted Patent: US 8,462,209 B2
• Time in Patent Office: Days
• US Class Current: 348/239
• CPC Class Codes: G01C 11/025 by scanning the object
• CPC Class Codes: H04N 23/45 for generating image signals from two or more image sensors being of different type or operating in different modes, e.g. with a CMOS sensor for moving images in combination with a charge-coupled device [CCD] for still images
• CPC Class Codes: H04N 23/698 for achieving an enlarged field of view, e.g. panoramic image capture
• CPC Class Codes: H04N 25/41 Extracting pixel data from a plurality of image sensors simultaneously picking up an image, e.g. for increasing the field of view by combining the outputs of a plurality of sensors

Abstract

A portable, aerial, dual-swath photogrammetric imaging system comprising twin nadir pointing CCD cameras for simultaneously acquiring twin adjacent digital images for merging into a large panorama. A pair of lens shifters symmetrically shift twin images to the left and right sides of the focal points of two parallel lenses to extend imaging swathwidth. The twin adjacent images of the imaging system have a strip of narrow overlap at the center of the whole scene that are reserved for photogrammetric processing and stitching twin images into a seamless panorama. Each camera is connected to an embedded computer which controls imaging data acquisition, attaches GPS/IMU measurements, generates KML metadata files for its snapshots, and stores acquired images and metadata into removable SSDs. Direct geo-referenced panoramic digital stills are immediately registered on to Google™ Earth precisely. Its images can be further processed for advanced mapping, change detection and GIS applications.

Claims

1. A dual-swath imaging system comprising:

a first CCD camera mounted on a remote sensing platform, said first CCD camera comprises a first CCD imager and a nadir pointing first optical lens;

a first lens shift mount attached between a body of said first camera and said first optical lens for shifting said first optical lens a predetermined distance with respect to said body of said first CCD camera and said first CCD imager;

a second CCD camera mounted on said platform adjacent to said first CCD camera, said second CCD camera comprises a second CCD imager and a nadir pointing second optical lens;

a second lens shift mount attached between a body of said second CCD camera and said second optical lens for shifting said second optical lens a predetermined distance with respect to said body of said second CCD camera body and said second CCD imager;

said first CCD camera comprises said first CCD imager positioned on a right side of said first focal point of said first optical lens for capturing a left scene image on a left side of said first focal point; and

said second CCD camera comprises said second CCD imager positioned on a left side of said second focal point of said second optical lens for capturing a right scene image on a right side of said second focal point.

2. The dual-swath imaging system as recited in claim 1 wherein said system comprises means for forming a dual-swath panoramic image by narrow overlapping of said left scene image and said right scene image at adjacent edges.

3. The dual-swath imaging system as recited in claim 1 wherein:

said first lens shift mount shifts said first optical lens a predetermined distance up to halfwidth of said first CCD imager; and

said second lens shift mount shifts said second optical lens a predetermined distance up to halfwidth of said second CCD imager.

4. The dual-swath imaging system as recited in claim 1 wherein said system comprises means for generating a trigger pulse for simultaneously activating said first camera and said second camera to acquire said left scene image and said right scene image.

5. A photogrammetric imaging system comprising:

a first CCD camera mounted on a platform having a nadir pointing first optical lens;

a second CCD camera mounted on said platform adjacent to said first CCD camera and having a nadir pointing second optical lens;

said first CCD camera comprises a first CCD imager positioned on a right side of a first focal point of said first optical lens for capturing a left scene image on a left side of said first focal point;

said second CCD camera comprises a second CCD imager positioned on a left side of a second focal point of a second optical lens for capturing a right scene image on a right side of said second focal point;

means for geo-referencing said left scene image;

means for storing said geo-referenced left scene image;

means for geo-referencing said right scene image;

means for storing said geo-referenced right scene image; and

means for merging said geo-referenced left scene image and said geo-referenced right scene image to form a dual-swath panorama.

6. The imaging system as recited in claim 5 wherein said system comprises means for forming a panorama by narrow overlapping of said left scene image and said right scene image at adjacent edges.

7. The imaging system as recited in claim 5 wherein said first optical lens attaches to a first lens shift mount and said second optical lens attaches to a second lens shift mount, said first lens shift mount being attached to said first CCD camera and said second lens shift mount being attached to said second CCD camera.

8. The imaging system as recited in claim 7 wherein said first shift mount and said second shift mount shift said first optical lens and said second optical lens whereby said first CCD imager and said second CCD imager are shifted on right and left focal points of said first optical lens and said second optical lens.

9. The imaging system as recited in claim 5 wherein said system comprises means for generating a trigger pulse for simultaneously activating said first camera and said second camera to acquire said left scene image and said right scene image.

10. The imaging system as recited in claim 5 wherein said left scene processing means comprises a first data acquisition system coupled to a first central processing unit.

11. The imaging system as recited in claim 5 wherein said right scene processing means comprises a second data acquisition system coupled to a second central processing unit.

12. The imaging system as recited in claim 5 wherein said left scene geo-referencing means comprises means for attaching real time GPS/IMU metadata measurements to each image captured and recorded.

13. The imaging system as recited in claim 5 wherein said right scene geo-referencing means comprises means for attaching real time GPS/IMU metadata measurements to each image captured and recorded.

14. The imaging system as recited in claim 6 wherein said means for forming a panoramic image by narrow overlapping of said left scene image and said right scene image comprises means for generating digital elevation models wherein a measured width of said overlapping field provides a real time above ground level height.

15. The imaging system as recited in claim 5 wherein said system comprises minimal size and weight for portability and use in manned and unmanned aerial vehicles.

16. A method for providing a dual-swath imaging system comprising the steps of:

mounting a first CCD camera on a remote sensing platform, said first CCD camera comprises a first CCD imager and a nadir pointing first optical lens;

attaching a first lens shift mount between a body of said first camera and said first optical lens for shifting said first optical lens a predetermined distance with respect to said first camera body and first CCD imager;

mounting a second CCD camera on said platform adjacent to said first CCD camera, said second CCD camera comprises a second CCD imager and a nadir pointing second optical lens;

attaching a second lens shift mount between a body of said second CCD camera and said second optical lens for shifting said second optical lens a predetermined distance with respect to said second CCD camera and said second CCD imager;

capturing a left scene image on a left side of said first focal point by said first CCD camera having said first CCD imager positioned on a right side of said first focal point of said first optical lens; and

capturing a right scene image on a right side of said second focal point by said second CCD camera having said second CCD imager positioned on a left side of said second focal point of said second optical lens.

17. The method as recited in claim 16 wherein said method comprises the step of forming a dual-swath panoramic scene by narrow overlapping of said left scene image and said right scene image at adjacent edges.

18. The method as recited in claim 16 wherein:

said step of attaching said first lens shift mount and shifting said first optical lens a predetermined distance includes providing said predetermined distance to be up to a halfwidth of said first CCD imager; and

said step of attaching said second lens shift mount and shifting said second optical lens a predetermined distance includes providing said predetermined distance to be up to a halfwidth of said second CCD imager.

19. The method as recited in claim 16 wherein said method comprises the step of providing for geo-referencing and stitching overlapped dual-swath left scene and right scene images onto a Google™

Earth Desktop comprising the steps of;

providing every frame of left scene and right scene images with IMU/GPS data to form frame metadata files;

providing every frame of left scene and right scene images with DEMs data from either USGS data base or a center strip width lookup table of a dual-swath panorama;

combining said frame metadata files with said DEMs data;

solving a left collinearity condition (x,y)=f(x_LEFT;

X, Y, Z) using combined inputs from said frame metadata files and said DEMs data to obtain a KML file for said left scene image;

solving a right collinearity condition (x,y)=f(x_RIGHT;

X, Y, Z) using combined inputs from said frame metadata files and said DEMs data to obtain a KML file for said right scene image;

converting left scene and right scene images into a left image JPEG file and a right image JPEG file;

combining said KML file for left image with said left image JPEG file;

registering said combined left image on said Google™

Earth Desktop;

combining said KML file for right image with said right image JPEG file; and

registering said combined right image on said Google™

Earth Desktop superimposed on said left image to form a freeze frame panorama image.