Correction of optical distortion by image processing

• US 20050007477A1
• Filed: 04/30/2004
• Published: 01/13/2005
• Est. Priority Date: 05/02/2003
• Status: Active Grant

• Current Assignee: Grandeye Limited (Oncam Global Group AG)
• Original Assignee: Grandeye Limited (Oncam Global Group AG)
• Inventors: Ahiska, Yavuz
• Granted Patent: US 7,529,424 B2
• Time in Patent Office: Days
• US Class Current: 348/335
• CPC Class Codes: H04N 23/62 Control of parameters via user interfaces
• CPC Class Codes: H04N 23/698 for achieving an enlarged field of view, e.g. panoramic image capture
• CPC Class Codes: H04N 23/81 for suppressing or minimising disturbance in the image signal generation

Abstract

The invention is a camera comprising the following. A camera that is capable of reducing distortion from an optical system has an optical system that is configured to capture a wide field of view of a subject. An image sensor and circuitry are coupled to the optical system and are configured to convert the output of the optical system to electrical signals suitable for use by an image processing circuit. The image processing circuit is coupled to the image sensor and is configured to reduce optical distortions from the combination of the optical system and the image sensor where the correction includes reference to a table of parameters held in a solid-state memory, attached to said image processing circuit, wherein the table of parameters may be specific to the particular combination of said optical system and said image.

Claims

1. A camera capable of reducing distortion from an optical system comprising:

a) an optical system capable of capturing a wide field of view;

b) an image sensor and circuitry coupled to said optical system and configured to convert the output of the said optical system to electrical signals suitable for use by an image processing circuit; and

c) the image processing circuit coupled to the image sensor and configured to reduce optical distortions from the combination of the optical system and the image sensor where the correction includes reference to a table of parameters held in a solid-state memory, attached to said image processing circuit, wherein the table of parameters may be specific to the particular combination of said optical system and said image sensor.

2. The camera of claim 1 in which the table of parameters has missing entries that are interpolated by the image processing circuit.

3. The camera of claim 1 in which the table of parameters is generated by photographing a test pattern through the optical system to be corrected and applying image processing operations to automatically produce the table of parameters.

4. The camera of claim 3 further comprising:

points of attachment coupled to the optical system and configured to support the test pattern.

5. The camera of claim 1 in which the table of parameters is generated by photographing a test pattern through the optical system to be corrected and manually constructing the table of parameters.

6. The camera of claim 5 further comprising:

points of attachment coupled to the optical system and configured to support the test pattern.

7. The camera of claim 1 wherein a plurality of tables of parameters are available to correct distortion for different focal lengths of the optical system, wherein an unrepresented focal length may be corrected by interpolating between some of the plurality of tables of parameters.

8. The camera of claim 1 wherein a plurality of tables of parameters are available to correct distortion for different apertures of the optical system, wherein an unrepresented aperture may be corrected by interpolating between some of the plurality of tables of parameters.

9. The camera of claim 1 wherein a plurality of tables of parameters are stored in the camera.

10. A camera capable with adjustable image projection distortion correction comprising:

a) an adjustable optical system capable of producing projection with variable optical geometric distortion;

b) an image sensor and circuitry coupled to the adjustable optical system and configured to convert the output of said adjustable optical system to electrical signals suitable for use by an image processing circuit;

c) said image processing circuit coupled to the image sensor and capable of correcting said optical geometric distortion where said correction includes reference to a table of geometric distortion parameters and where more than one said table is used to correct optical distortion that varies according to changes in the projection from said adjustable projection optical system onto said image sensor and said tables to be automatically selected as said projection adjusted and unrepresented projections corrected by interpolating between existing tables; and

d) said multiple table of parameters held in solid-state memory within housing of said adjustable projection optical system, and said image processing circuit.

11. The camera of claim 10 in which more than one table is configured to be used to correct optical geometric distortion that varies according to one or more parameters of said optical system, said tables to be automatically selected as said parameter varies and unrepresented parameters corrected by interpolating between said tables.

12. A camera capable of reducing optical distortion comprising:

a) a detachable optical system to capture a capable of capturing wide field of view;

b) an image sensor and circuitry coupled to the optical system and configured to convert the output of said optical system to electrical signals suitable for use by an image processing circuit;

c) said image processing circuit coupled to the image sensor and capable of reducing optical distortions introduced by the combination of said optical system and said image sensor where said correction includes reference to a table of parameters;

d) said table of parameters held in a solid-state memory coupled to said optical system, said image processing circuit gaining access to said table on attachment of said optical system to said camera.

13. A method of reducing geometric distortion in an optical system comprising:

a) capturing a distorted image of a known test pattern through said optical system;

b) defining a mapping between said distorted image of said test pattern and an undistorted test pattern through automatic, semi-automatic, or manual means;

c) constructing a table of mapping information in a form suitable for use by an image processing circuit; and

d) using said image-processing circuit to apply said table to images subsequently or previously captured through said optical system.

14. A method of reducing intentional geometric distortion in an optical system comprising:

a) constructing a table of mapping information based upon theoretical mathematical principles in a form suitable for use by an image processing circuit; and

b) using said image-processing circuit to apply said table to images subsequently or previously captured through said optical system.