System and method for calibrating and adjusting a projected image of a projection apparatus

• US 8,311,366 B2
• Filed: 01/12/2007
• Issued: 11/13/2012
• Est. Priority Date: 01/13/2006
• Status: Active Grant

• Current Assignee: Fraunhofer Gesellschaft Zur Foerderung Der Angewandten Forsching E.V.
• Original Assignee: Fraunhofer Gesellschaft Zur Foerderung Der Angewandten Forsching E.V.
• Inventors: Schiewe, Manuel, Klose, Stefan
• Primary Examiner(s): ZARKA, DAVID PETER
• Application Number:
  US12/160,289
• Publication Number:
  US 20090067749A1
• Time in Patent Office: 2,132 Days
• Field of Search: 382/294
• US Class Current: 382/294
• CPC Class Codes: H04N 9/3147 Multi-projection systems displays in general H04N9/12; video walls G06F3/1446, G09G2300/026
• CPC Class Codes: H04N 9/3185 Geometric adjustment, e.g. keystone or convergence optical or mechanical adjustment of convergence H04N9/317; using scanning means H04N3/22; optical or mechanical adjustments of projectors not peculiar to the presence of an electronic spatial light modulator G03B21/14
• CPC Class Codes: H04N 9/3194 including sensor feedback

Abstract

The invention relates to a calibration method and system for at least one projection apparatus, where the geometric data from at least one projection area has been or are stored in advance in a computer unit, wherein a) the at least one projection apparatus projects previously known calibration patterns onto at least one portion of the projection area, with the calibration patterns having at least one overlap region among one another, b) the calibration patterns are recorded by at least one camera apparatus as a calibration image, where c) the computer unit is used to automatically ascertain the difference between the recorded real calibration image and an ideal depiction result from the previously known calibration pattern on the projection area as a reference pattern, and where subsequently the difference between the real calibration image and the reference pattern is used to ascertain a correction transform.

Claims

1. A calibration method for at least one projection apparatus for projecting images onto at least one projection area, wherein the at least one projection area is associated with geometric data having been or being stored in advance in a computer unit, comprising:

a) projecting, with the at least one projection apparatus, previously known calibration patterns onto at least a portion of the at least one projection area,

b) recording the previously known calibration patterns by at least one camera apparatus as a calibration image, wherein data of the calibration image is transmitted to the computer unit,

c) automatically determining, by means of the computer unit, a deviation between the recorded calibration image and an ideal imaging result of the previously known calibration patterns on the at least one projection area, the ideal imaging result forming a reference pattern, wherein an actual arrangement of the at least one projection area, of the at least one projection apparatus, and of the camera apparatus is modeled in a virtual three-dimensional model according to known geometric data of the at least one projection area, of the at least one projection apparatus, and of the camera apparatus, and

d) determining, by means of the computer unit, a correction transform from the deviation between the recorded calibration image and the reference pattern such that a transformation of a real projection of images by means of the correction transform by the at least one projection apparatus corresponds, particularly in an overlap region, with the reference pattern apart from a minimum deviation, wherein the correction transform causes a displacement of at least one point of the recorded calibration image onto a point of the reference pattern.

2. The calibration method as claimed in claim 1, further comprising:

aligning overlapping projections of at least two projection apparatuses by minimizing the deviation from the reference pattern so that no discontinuities are visible in the overlap region.

3. The calibration method as claimed in claim 1, wherein the at least one projection area consists at least partially of at least one of the group of a spherical shell, a cylindrical shell and a planar surface.

4. The calibration method as claimed in claim 1, wherein the at least one camera apparatus comprises at least one of the group of at least one digital camera, at least one video camera, at least one fish-eye camera and at least one webcam.

5. The calibration method as claimed in claim 1, wherein the at least one camera apparatus is mounted rotatably on at least one axis in order to record an image of the at least one projection area.

6. The calibration method as claimed in claim 1, wherein the at least one projection apparatus comprises at least one of the group of a beamer, laser projector, LCD projector and DLP projector.

7. The calibration method as claimed in claim 1, wherein at least one calibration pattern is a strip pattern in which individual strips are arranged parallel to one another.

8. The calibration method as claimed in claim 1, wherein at least one calibration pattern comprises at least one of the group of curved, predistorted, single-color, multicolor and color-coded strips.

9. The calibration method as claimed in claim 1, wherein at least one calibration pattern has a point pattern.

10. The calibration method as claimed in claim 1, further comprising:

recording, by means of the at least one camera apparatus, a black and white image before evaluating a recording of at least one calibration pattern.

11. The calibration method as claimed in claim 1, further comprising:

blending in the overlap region in order to adapt brightness values.

12. The calibration method as claimed in claim 1, further comprising:

automatically varying at least one spatial orientation of the at least one projection apparatus as a function of the correction transform.

13. The calibration method as claimed in claim 1, further comprising:

automatically determining parameters of the at least one camera apparatus by making a recording of a previously known pattern, in particular a marker pattern on the at least one projection area, and by calculating the parameters of the at least one camera apparatus therefrom with the aid of the computer unit.

14. A calibration system comprising:

a) at least one projection apparatus for projecting images onto at least one projection area, the geometric data of the at least one projection area having been or being stored in advance in a computer unit, with at least one projection apparatus projecting previously known calibration patterns onto at least a portion of the at least one projection area;

b) at least one camera apparatus for recording the previously known calibration patterns as a calibration image, it being possible to transmit data of the calibration image to the computer unit; and

c) with the computer unit, automatically determining a deviation between the recorded calibration image and an ideal imaging result of the previously known calibration patterns on the at least one projection area, the ideal imaging result forming a reference pattern, wherein an actual arrangement of the at least one projection area, of the at least one projection apparatus, and of the camera apparatus is modeled in a virtual three-dimensional model according to known geometric data of the at least one projection area, of the at least one projection apparatus, and of the camera apparatus; and

d) a correction means for determining a correction transform from the deviation between the recorded calibration image and the reference pattern such that a transformation of a real projection of images by means of the correction transform by the at least one projection apparatus corresponds, particularly in an overlap region, with the reference pattern apart from a minimum deviation, wherein the correction transform causes a displacement of at least one point of the recorded calibration image onto a point of the reference pattern.