System and method for determining an imaging deviation of a camera

• US 10,440,357 B2
• Filed: 06/13/2012
• Issued: 10/08/2019
• Est. Priority Date: 07/05/2011
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Schmack, Andreas, Apel, Uwe
• Primary Examiner(s): Harold, Jefferey F
• Assistant Examiner(s): Satti, Humam
• Application Number:
  US14/131,161
• Publication Number:
  US 20140204220A1
• Time in Patent Office: 2,673 Days
• Field of Search: 348180, 348187, 348188
• CPC Class Codes: G02B 27/62 Optical apparatus specially adapted for adjusting optical elements during the assembly of optical systems
• CPC Class Codes: G03B 43/00 Testing correct operation of photographic apparatus or parts thereof
• CPC Class Codes: H04N 17/002 for television cameras

Abstract

A system is described for determining an imaging deviation of a camera having: the camera, which is focused on a first distance, having a target pattern unit, which is situated at a second distance from the camera in a field of view of the camera and which has a three-dimensional surface texture having calibration markings, having a lens unit which is situated at a third distance from the camera and between the target pattern unit and the camera and is developed so that the three-dimensional surface texture is able to be imaged by the camera, and having a control unit that is connected to the camera and which is developed so that the imaging deviation of the camera is determinable by evaluating an image taken of the calibration markings of the three-dimensional surface texture. Also described is a method for determining an imaging deviation of a camera.

Claims

1. A system for determining an imaging deviation of a camera, comprising:

the camera having a camera lens focused on a first distance;

a target pattern unit situated at a second distance from the camera in a field of view of the camera, wherein the target pattern unit has a three-dimensional surface texture including calibration markings having a known spatial geometric system, and wherein the calibration markings are provided at various object distances for a calibration;

a lens unit situated at a third distance from the camera and between the target pattern unit and the camera lens, the lens unit being configured so that the three-dimensional surface texture is able to be imaged by the camera; and

a control unit connected to the camera and configured so that the imaging deviation of the camera is determinable by evaluating an image taken of the calibration markings of the three-dimensional surface texture to check for a correct focus position of the camera and for a parallel alignment of an image sensor with the image plane.

2. The system as recited in claim 1, wherein a deviation of at least one of a depth of field and a focal position of the camera is determinable as the imaging deviation of the camera.

3. The system as recited in claim 1, wherein at least one of a pitch deviation, a yaw deviation, and a roll deviation is determinable as the imaging deviation of the camera.

4. The system as recited in claim 1, wherein at least one of an imaging error, a spherical aberration, an astigmatism, and a field curvature is determinable as the imaging deviation of the camera.

5. The system as recited in claim 1, further comprising:

a light source configured so that the calibration markings are able to be illuminated one of reflectively, transflectively, and transmissively.

6. The system as recited in claim 5, wherein the light source is tunable in a wavelength.

7. The system as recited in claim 1, wherein the image of the calibration markings is able to be taken by light having different wavelengths, and the imaging deviation of the camera is determinable as a function of a wavelength.

8. The system as recited in claim 1, wherein the lens unit includes an optical component having a variable focal length controllable by the control unit.

9. The system as recited in claim 1, wherein the calibration markings are configured at least one of as stripe patterns having different strip widths, as squares having a different orientations, and as alphanumeric symbols.

10. The system as recited in claim 1, further comprising:

a light source configured so that the calibration markings are able to be illuminated one of reflectively, transflectively, and transmissively;

wherein a deviation of at least one of a depth of field and a focal position of the camera is determinable as the imaging deviation of the camera, and wherein the light source is tunable in a wavelength.

11. The system as recited in claim 1, further comprising:

a light source configured so that the calibration markings are able to be illuminated one of reflectively, transflectively, and transmissively;

wherein at least one of a pitch deviation, a yaw deviation, and a roll deviation is determinable as the imaging deviation of the camera, and wherein the light source is tunable in a wavelength.

12. The system as recited in claim 1, further comprising:

a light source configured so that the calibration markings are able to be illuminated one of reflectively, transflectively, and transmissively;

wherein at least one of an imaging error, a spherical aberration, an astigmatism, and a field curvature is determinable as the imaging deviation of the camera, and wherein the light source is tunable in a wavelength.

13. The system as recited in claim 1, further comprising:

a light source configured so that the calibration markings are able to be illuminated one of reflectively, transflectively, and transmissively;

wherein the light source is tunable in a wavelength, and

wherein the image of the calibration markings is able to be taken by light having different wavelengths, and the imaging deviation of the camera is determinable as a function of a wavelength.

14. The system as recited in claim 1, further comprising:

a light source configured so that the calibration markings are able to be illuminated one of reflectively, transflectively, and transmissively;

wherein the light source is tunable in a wavelength, and

wherein the lens unit includes an optical component having a variable focal length controllable by the control unit.

15. The system as recited in claim 1, further comprising:

a light source configured so that the calibration markings are able to be illuminated one of reflectively, transflectively, and transmissively;

wherein the light source is tunable in a wavelength, and

wherein the calibration markings are configured at least one of as stripe patterns having different strip widths, as squares having a different orientations, and as alphanumeric symbols.

16. A method for determining an imaging deviation of a camera, comprising:

focusing the camera on a first distance, wherein the camera includes a camera lens;

arranging a target pattern unit, wherein the target pattern unit has a three-dimensional surface texture having calibration markings having a known spatial geometric system, at a second distance from the camera, wherein the calibration markings are provided at various object distances for a calibration;

inserting a lens unit situated at a third distance from the camera and between the target pattern unit and the camera lens for imaging the three-dimensional surface texture by the camera;

taking an image of the calibration markings of the three-dimensional surface texture by the camera; and

determining the imaging deviation of the camera by a control unit by evaluating the image taken to check for a correct focus position of the camera and for a parallel alignment of an image sensor with the image plane.

17. The method as recited in claim 16, wherein at least one of a deviation of at least one of a depth of field and a focal position of the camera is determined as the imaging deviation of the camera.

18. The method as recited in claim 16, wherein at least one of a pitch deviation, a yaw deviation, and a roll deviation of the camera is determined as the imaging deviation of the camera.

19. The method as recited in claim 16, wherein at least one of an imaging error, a spherical aberration, an astigmatism, and a field curvature is determinable as the imaging deviation of the camera.

20. The method as recited in claim 16, wherein the image of the calibration markings is taken by light having different wavelengths, and the imaging deviation of the camera is determined as a function of a wavelength.

21. A method for determining an imaging deviation of a camera, the method comprising:

focusing the camera on a first distance, wherein the camera includes a camera lens and the camera lens is focused on a hyperfocal distance;

arranging a target pattern unit, wherein the target pattern has a three-dimensional surface texture having calibration markings K1-Kn having a known spatial geometric system, at a second distance from the camera, and wherein the calibration markings are provided at various object distances for a calibration;

imaging, using the camera and using a lens unit situated at a third distance from the camera and between the target pattern unit and the camera lens, the surface texture; and

taking an image, using the camera, of the calibration markings K1-Kn of the three-dimensional surface texture;

wherein the imaging deviation of the camera is performed by a control unit which evaluates the image taken by the camera,

wherein a deviation of an imaging characteristic of the camera is determined,

wherein the determining of the imaging deviation includes determining a movement characteristic of the camera to check for a correct focus position of the camera and for a parallel alignment of an image sensor with the image plane, and

wherein an imaging error of the camera is determined.

22. The method of claim 21, wherein:

the hyperfocal distance in a range of 25 m to 300 m,

the image of calibration markings K1-Kn is taken by light having different wavelengths, and an imaging deviation of the camera is determined as a function of a wavelength,

the deviation includes at least one of a deviation of a depth of field and a focal length of the camera,

the movement characteristic of the camera includes at least one of a pitch deviation, a yaw deviation, and a roll deviation, and

wherein the imaging error of the camera is based on at least one of a spherical aberration, an astigmatism and a field curvature.

23. The method of claim 21, wherein the hyperfocal distance in a range of 25 m to 300 m, and wherein the image of calibration markings K1-Kn is taken by light having different wavelengths, and an imaging deviation of the camera is determined as a function of a wavelength.

24. The method of claim 21, wherein the deviation includes at least one of a deviation of a depth of field and a focal length of the camera, wherein the movement characteristic of the camera includes at least one of a pitch deviation, a yaw deviation, and a roll deviation, and wherein the imaging error of the camera is based on at least one of a spherical aberration, an astigmatism and a field curvature.