Wide Field of View Reflector and Method of Designing and Making Same

• US 20140009571A1
• Filed: 06/24/2013
• Published: 01/09/2014
• Est. Priority Date: 11/23/2006
• Status: Abandoned Application

• Current Assignee: Zheng Jason Geng
• Original Assignee: Zheng Jason Geng
• Inventors: Geng, Zheng Jason
• Application Number:
  US13/925,728
• Publication Number:
  US 20140009571A1
• Time in Patent Office: Days
• US Class Current: 348/36
• CPC Class Codes: G08B 13/19628 of wide angled cameras and camera groups, e.g. omni-directional cameras, fish eye, single units having multiple cameras achieving a wide angle view
• CPC Class Codes: G08B 13/19643 wherein the cameras play different roles, e.g. different resolution, different camera type, master-slave camera
• CPC Class Codes: G08B 13/19697 Arrangements wherein non-video detectors generate an alarm themselves
• CPC Class Codes: H04N 23/698 for achieving an enlarged field of view, e.g. panoramic image capture
• CPC Class Codes: H04N 7/183 for receiving images from a single remote source

Abstract

A system and method for designing and using freeform reflectors to collect images of a wide angle field-of-view scene is provided. A freeform reflector may enable a wide angle field-of-view to be collected in an unwarped and unwrapped manner such that computer processing may be eliminated. Furthermore, the use of a freeform reflector allows for larger areas of an image sensor chip to be used, thereby providing higher resolution images. Because freeform reflectors may be configured to map a scene onto the image sensor chip in a scalar and mathematically correct manner, output images may be directly displayed from the image sensor chip. Wide angle field-of-view imaging systems, such as surveillance, alarm, and projector system, may utilize freeform reflectors as provided herein.

Claims

1-5. -5. (canceled)

6. A method for collecting an electromagnetic signal, said method comprising:

acquiring an electromagnetic signal representing a predefined field-of-view of a scene;

reflecting the acquired electromagnetic signal from a freeform swiace configured by a predefined mapping function to map the acquired electromagnetic signal onto pixels of a sensor; and

sensing the reflected electromagnetic signal as mapped from the predefined field-of-view of the scene by the pixels of the sensor.

7. The method according to claim 6, wherein reflecting the acquired electromagnetic signal includes reflecting an optical signal.

8. The method according to claim 6, wherein sensing the reflected electromagnetic signal includes sensing the electromagnetic signal using a pixel configuration having a predetermined shape that is used in defining the predefined mapping function.

9. The method according to claim 6, wherein acquiring an electromagnetic signal of a scene from a predefined field-of-view is from a field-of-view ranging up to 360 degrees.

10. The method according to claim 6, wherein reflecting causes an optical processing the electromagnetic signal to occur prior to sensing the reflected electromagnetic signal.

11. A method for designing a freeform reflector, said method comprising:

defining a scene having a predetermined wide angle field-of-view;

determining sensor parameters of a sensor having a pixel configuration arranged to sense an electromagnetic signal;

defining a mapping relationship between the scene and sensor parameters; and

generating a mapping function that causes the scene to be reflected onto the sensor pixels based on the defined mapping relationship between the scene and sensor parameters, the mapping function defining a freeform reflector.

12. The method according to claim 11, wherein defining the mapping relationship between the scene and sensor parameters includes defining the mapping relationship such that at least 70 percent of the pixels of the sensor receives the electromagnetic signal when reflected from the freeform reflector.

13. The method according to claim 11, further comprising producing a freeform reflector surface by forming a plurality of individual pixel dispersed projections, wherein each pixel projection is individually determined to correspond to a previously calculated scene map and wherein a collection of all projection data points form geometry of the freeform reflector surface.

14. The method according to claim 11, wherein generating the mapping function includes:

establishing a first point in the scene to map onto a first predetermined pixel of the sensor;

forming a first vector from the established point to a reflection location;

forming a second vector from the reflection location to the predetermined pixel of the sensor;

determining a local surface normal vector extending the reflection location, the local surface normal vector defining a surface of the freeform reflector; and

repeating establishing, forming, forming and determining for multiple points in the scene to map onto other predetermined pixels of the sensor.

15. The method according to claim 11, wherein generating a mapping function includes generating a mapping function that lUlwarp5 arrangement of the electromagnetic signal in response to reflecting from the freeform reflector to generate a substantially undistorted image.

16. A method of designing a mirror, said method comprising:

defining a scene having a predetermined field-of-view;

defining a first sub-scene of the scene;

defining a second sub-scene of the scene;

determining sensor parameters of an optical sensor having a pixel array configuration, the pixel array configured to sense optical signals;

defining a first sub-array of the optical pixel array;

defining a second sub-array of the optical pixel array, the second sub-array being mutually exclusive of the first sub-array;

defining a first mapping relationship between the first sub-scene and the first sub-array;

defining a second mapping relationship between the second sub-scene and the second sub-array;

generating a first mapping function that, when used to define a first portion of a freeform optical reflective surface, causes the first sub-scene to be reflected from the first portion of the freeform optical reflective surface onto the first sub-array; and

generating a second mapping function that, when used to define a second portion of the freeform optical reflective surface, causes the second sub-scene to be reflected from the second portion of the freeform optical reflective surface onto the second sub-array.

17. The method according to claim 16, wherein defining the first and second sub-array includes defining each of the first and second sub-array with different definitions of areas of the optical pixel array.

18. The method according to claim 16, wherein generating the first mapping function includes generating an order of mapping corresponding the first sub-scene with the first sub-array.

19. The method according to claim 16, wherein generating the first and second mapping functions includes generating first and second mapping functions for sensing panoramic views of the first and second sub-scenes using the first and second sub-arrays, respectively.

20. The method according to claim 16, wherein generating the first and second mapping functions includes generating first and second mapping functions for sensing hemispherical views of the first and second sub-scenes using the first and second sub-arrays, respectively.

21-25. -25. (canceled)