Electro-optical Foveated Imaging and Tracking System

• US 20090080695A1
• Filed: 09/24/2007
• Published: 03/26/2009
• Est. Priority Date: 09/24/2007
• Status: Active Grant

• Current Assignee: New Span Opto-Technology Inc.
• Original Assignee: New Span Opto-Technology Inc.
• Inventors: Yang, Jianwen
• Granted Patent: US 7,973,834 B2
• Time in Patent Office: Days
• US Class Current: 382/103
• CPC Class Codes: G06V 10/255 Detecting or recognising potential candidate objects based on visual cues, e.g. shapes
• CPC Class Codes: G06V 10/92 using spatial domain filters, e.g. joint transform correlators

Abstract

Conventional electro-optical imaging systems can not achieve wide field of view (FOV) and high spatial resolution imaging simultaneously due to format size limitations of image sensor arrays. To implement wide field of regard imaging with high resolution, mechanical scanning mechanisms are typically used. Still, sensor data processing and communication speed is constrained due to large amount of data if large format image sensor arrays are used. This invention describes an electro-optical imaging system that achieves wide FOV global imaging for suspect object detection and local high resolution for object recognition and tracking. It mimics foveated imaging property of human eyes. There is no mechanical scanning for changing the region of interest (ROI). Two relatively small format image sensor arrays are used to respectively acquire global low resolution image and local high resolution image. The ROI is detected and located by analysis of the global image. A lens array along with an electronically addressed switch array and a magnification lens is used to pick out and magnify the local image. The global image and local image are processed by the processor, and can be fused for display. Three embodiments of the invention are descried.

Claims

1. ) An electro-optical foveated imaging and tracking system comprising:

A) a primary imaging lens;

B) an image transfer device;

C) an image readout light beam;

D) two image relay channels;

E) a local image magnifying subsystem;

F) two image detection devices;

G) a switcher array;

H) a processor;

I) a display screen.

2. ) A primary lens as described in claim 1 wherein working at a specified waveband, could be optical components group comprising refractive or reflective components;

3. ) An image transfer device as described in claim 1 wherein the scene image of designated waveband presented on its input surface, transferring the input image to its output surface for readout;

4. ) An image readout light beam as described in claim 1 includes a spot white light source, a collimation lens and a beam splitter, the beam illuminating on the readout surface of the image transfer device described in claim 3 and reflected pattern containing scene details;

5. ) The two image relay channels as described in claim 1 each consisting of 4-f optical configuration with the first lens for common use and a beam splitter locating at focal plane to separate the beam into two channels;

6. ) The local image magnifying subsystem as described in claim 1 consisting of a lens array, a switcher array, and a magnification lens, wherein each sub-lens of the lens array and the magnification lens forming a revised telescope configuration to enlarge local image corresponding to the sub-lens;

7. ) The switcher array as described in claim 6 is addressed by an electronic signal to open a specified unit that is relevant to the ROI location;

8. ) The two image detection devices as described in claim 1 are sensitive to the readout beam, wherein one device is located at the relayed image as described in claim 5 and is used to acquire the global image and the other is located on the back focal plane of the magnification lens as described in claim 6 and is used to acquire local magnified image;

9. ) The processor as described in claim 1 is a controller and is also a computing system, wherein programs with image processing functions and automatic target detection algorithms are included;

10. ) The display screen as described in claim 1 is used to display the acquired global image and local image as described in claim 8. Human/screen interface is included for manually pointing to the region of interest on the global image;

11. ) The acquired global image as described in claim 8 is analyzed and processed by the processor as described in claim 9. Region of interest of the global scene is determined by the processor or by direct human eye monitoring;

12. ) The location information of region of interest determined in claim 11 is sent to the switcher array to open the corresponding unit to allow the local image passing and be magnified.

13. ) An electro-optical foveated imaging and tracking system comprising:

A) a camera lens;

B) an image splitting device;

C) a local image magnifying subsystem;

D) two image acquisition devices;

E) a switcher array;

F) a processor;

G) a display screen.

14. ) A camera lens as described in claim 13 wherein working at specified waveband, could be optical components group comprising refractive or reflective components;

15. ) An image splitting device as described in claim 13 splits the image acquired by the camera lens as descried in claim 14 into two channels, one channel for global imaging and the other for local magnification;

16. ) The local image magnifying subsystem as described in claim 13 comprising a lens array, a switcher array, and a magnification lens, wherein each sub-lens of the lens array and the magnification lens forming a revised telescope configuration to enlarge local image corresponding to the sub-lens;

17. ) The switcher array as described in claim 16 is addressed by an electronic signal to open a specified unit that is relevant to the ROI location;

18. ) The two image acquisition devices as described in claim 13 are sensitive to the waveband of interested scene, wherein one device is located at the transmitted image of the image splitting device as described in claim 15 and is used to acquire the global image and the other is located on the back focal plane of the magnification lens as described in claim 16 and is used to acquire local magnified image;

19. ) The processor as described in claim 13 is a controller and is also a computing system, wherein programs with image processing functions and automatic target detection algorithms are included;

20. ) The display screen as described in claim 13 is used to display the acquired global image and local image as described in claim 18. Human/screen interface is included for manually pointing to the region of interest on the global image;

21. ) The acquired global image as described in claim 18 is analyzed and processed by the processor as described in claim 19. Region of interest of the global scene is determined by the processor or by direct human eye monitoring;

22. ) The location information of region of interest determined in claim 21 is sent to the switcher array to open the corresponding unit to allow the local image passing and magnification.

24. ) A camera lens as described in claim 13 wherein working at a specified waveband, could be optical components group comprising refractive or reflective components;

23. ) An electro-optical foveated imaging and tracking system comprising:

A) a camera lens;

B) a micro-mirrors array device;

C) two image relay devices;

D) a local image magnifying subsystem;

E) two image acquisition devices;

F) a switcher array;

G) a processor;

H) a display screen.

25. ) A micro-mirrors array device as described in claim 23 selects and redirects the selected portion of image acquired by the camera lens as descried in claim 24 into two channels, one channel for global imaging and the other for local magnification;

26. ) The two image relay devices as described in claim 23 each comprising aspherical mirror and/or refractive lens to respectively relay the selected portion of the image on micro-mirrors array device in the two channels as described in claim 25;

27. ) The local image magnifying subsystem as described in claim 23 comprising a lens array, a switcher array, and a magnification lens, wherein each sub-lens of the lens array and the magnification lens forming a revised telescope configuration to enlarge local image corresponding to the sub-lens;

28. ) The switcher array as described in claim 27 is addressed by an electronic signal to open a specified unit that is relevant to the ROI location;

29. ) The two image acquisition devices as described in claim 23 are sensitive to the waveband of interested scene, wherein one device is located at the relayed image of the global imaging channel as described in claim 25 and is used to acquire the global image and the other is located on the back focal plane of the magnification lens as described in claim 27 and is used to acquire local magnified image;

30. ) The processor as described in claim 23 is a controller and is also a computing system, wherein programs with image processing functions and automatic target detection algorithms are included;

31. ) The display screen as described in claim 23 is used to display the acquired global image and local image as described in claim 29. Human/screen interface is included for manually pointing to the region of interest on the global image;

32. ) The acquired global image as described in claim 29 is analyzed and processed by the processor as described in claim 30. Region of interest of the global scene is determined by the processor or by direct human eye monitoring;

33. ) The location information of region of interest determined in claim 32 is sent to the switcher array to open the corresponding unit to allow the local image passing and magnification.