Wide-angle image dewarping method and apparatus

• US 6,005,611 A
• Filed: 08/04/1998
• Issued: 12/21/1999
• Est. Priority Date: 05/27/1994
• Status: Expired due to Term

• Current Assignee: BH Image Co LLC (Intellectual Ventures LLC)
• Original Assignee: Be Here Corporation
• Inventors: Gullichsen, Eric, Wyshynski, Susan
• Primary Examiner(s): HO, TUAN V
• Application Number:
  US09/128,963
• Time in Patent Office: 504 Days
• Field of Search: 348/36, 348/25, 348/20, 348/143, 348/147, 348/37, 348/38, 348/39, 382/293, 382/294, 382/300, 382/285, 382/153, 382/154, 345/427, 345/425, 345/430, 345/436
• US Class Current: 348/211.6
• CPC Class Codes: G06T 3/047 Fisheye or wide-angle transformations
• CPC Class Codes: G06T 3/12 Panospheric to cylindrical image transformations
• CPC Class Codes: H04N 5/2628 Alteration of picture size, shape, position or orientation, e.g. zooming, rotation, rolling, perspective, translation

Abstract

A method and apparatus for transforming wide angle video into perspective corrected viewing zones which either a single user or multiple users may select, orient and magnify. The present invention first captures a wide angle digital video input by any suitable means. The captured image is then stored in a suitable memory means so portions of the image may be selected at a later time. When a portion of the stored video is selected for viewing, a plurality of discrete viewing vectors in three dimensional space are chosen on the video input and transformed to a plurality of control points in a two dimensional plane or any other suitable surface. The area between these points which is still warped from the original wide angle image capture is then transformed to a perspective corrected field of view. The perspective corrected field of view is then displayed on a suitable displaying apparatus, such as a monitor or head mounted display.

Claims

1. A method of performing perspective correction, said method comprising:

capturing a distorted image with a wide-angle lens;

transforming a set of control vectors into a set of control points using a function that models said wide angle lens;

generating a polynomial transform function that maps said control points into rectangular points; and

transforming a sub area of said distorted image proximate to said control points using said polynomial transform function.

2. The method of claim 1 wherein said polynomial transformation comprises a global bivariate polynomial transformation.

3. The method of claim 1 wherein said polynomial transformation comprises a biquadratic polynomial transformation.

4. The method of claim 1 wherein said set of control vectors comprise a principal viewing and eight surrounding vectors that form a rectangular view.

5. The method of claim 1 wherein said wide-angle lens comprises a fish eye lens.

6. The method of claim 1 wherein said image capture system comprises a video digitizer.

7. The method of claim 1 wherein said transformation is performed by a hardware texture mapping device.

8. A computer apparatus for performing perspective correction, said apparatus comprising:

an image capture system for capturing a distorted image with a wide-angle lens;

a processor, said processor for transforming a set of control vectors into a set of control points using a function that models said wide angle lens and generating a polynomial transform function that maps said control points into rectangular points; and

a transform engine, said transform engine transforming a sub area of said distorted image proximate to said control points using said polynomial transform function.

9. The computer apparatus of claim 8 wherein said polynomial transformation comprises a global bivariate polynomial transformation.

10. The computer apparatus of claim 8 wherein said polynomial transformation comprises a biquadratic polynomial transformation.

11. The computer apparatus of claim 8 wherein said set of control vectors comprise a principal viewing and eight surrounding vectors that form a rectangular view.

12. The computer apparatus of claim 8 wherein said wide-angle lens in said image capture system comprises a fish eye lens.

13. The computer apparatus of claim 8 wherein said image capture system comprises a video digitizer.

14. The computer apparatus of claim 8 wherein said transformation is performed by a hardware texture-mapping device.

15. A computer readable medium storing a method of performing perspective correction that operates by:

capturing a distorted image with a wide-angle lens;

transforming a set of control vectors into a set of control points using a function that models said wide angle lens;

generating a polynomial transform function that maps said control points into rectangular points; and

transforming a sub area of said distorted image proximate to said control points using said polynomial transform function.

16. The computer readable medium of claim 15 wherein said polynomial transformation comprises a global bivariate polynomial transformation.

17. The computer readable medium of claim 15 wherein said polynomial transformation comprises a biquadratic polynomial transformation.

18. The computer readable medium of claim 15 wherein said set of control vectors comprise a principal viewing and eight surrounding vectors that form a rectangular view.

19. The computer readable medium of claim 15 wherein said wide-angle lens comprises a fish eye lens.

20. The computer readable medium of claim 15 wherein said transformation is performed by a hardware texture mapping device.