Method for a distortion-free display

• US 7,999,760 B2
• Filed: 12/27/2007
• Issued: 08/16/2011
• Est. Priority Date: 06/29/2005
• Status: Expired due to Fees

• Current Assignee: Bayerische Motoren Werke AG
• Original Assignee: Bayerische Motoren Werke AG
• Inventors: Mangold, Thomas, Loh, Sebastian, Pinsker, Martin, Giegold, Juergen
• Primary Examiner(s): Wang; Quan-Zhen
• Assistant Examiner(s): NGUYEN, JENNIFER T
• Application Number:
  US11/964,944
• Publication Number:
  US 20080165084A1
• Time in Patent Office: 1,328 Days
• Field of Search: 345 7- 9, 345/204, 349/11, 359/630, 359/618, 359/709
• US Class Current: 345/7
• CPC Class Codes: G06T 5/80 Geometric correction

Abstract

A method is provided for a distortion-free display of image elements, which are composed of computer-generated pixels and are reflected on a non-planar reflective surface, in particular a windshield of a motor vehicle. According to this method, pre-distorted image data are calculated by a computer unit in an operating phase as a function of the distortion properties of the reflective surface from the original image data of the image elements in accordance with the display-related pre-distortion parameters and are transferred to a display unit, which projects the image elements onto the reflective surface. In order to obtain the display-related pre-distortion parameters, at least one image element is provided, pre-distorted and projected in the form of original image data in a calibration phase in a procedure that is analogous to the operating phase; and the image data resulting from the projection are recorded using a camera and image processing, and compared with the original image data. During the calibration phase, at least two image data sets resulting from the projection are recorded from different camera positions and/or camera viewing angles.

Claims

1. A method for displaying image elements, composed of computer-generated pixels and reflected on a non-planar reflective surface, for a substantially distortion-free display the method comprising the acts of:

calculating pre-distorted image data by a computer unit in an operating phase, based on distortion characteristics of the reflected surface, from original image data of the image elements in accordance with pre-distortion parameters related to a display;

transferring the pre-distorted image data to a display device, and projecting image elements onto the reflective surface;

in order to obtain the pre-distortion parameters related to the display device, in a calibration phase recording at least two image data records captured from at least one of different camera positions and camera angles, the recorded at least two image data records resulting from a projection of at least one image element that is pre-distorted and projected in a form of original image data using a same procedure as in an operating phase, wherein the recorded at least two image data sets is compared with the original image data.

2. The method according to claim 1, wherein in the calibration phase, the at least two recorded image data sets are recorded chronologically in succession from the at least one of the different camera positions and the camera viewing angles using a single camera.

3. The method according to claim 2, wherein in both the calibration phase and the operating phase, in addition to pre-distortion via the computer unit, a pre-distortion is performed via optical elements arranged in front of the reflective surface.

4. The method according to claim 2, wherein the method is used for the substantially distortion-free display of image elements projected on a windshield of a motor vehicle, and that the cameras that are used for recording the image are positioned in the motor vehicle and/or mounted on the motor vehicle exclusively for recording images in the calibration phase.

5. The method according to claim 1, wherein at least one of the at least two image data sets is recorded by way of at least two cameras, which cameras are mounted in at least one of different positions and viewing angles.

6. The method according to claim 5, wherein in both the calibration phase and the operating phase, in addition to pre-distortion via the computer unit, a pre-distortion is performed via optical elements arranged in front of the reflective surface.

7. The method according to claim 1, wherein in both the calibration phase and the operating phase, in addition to pre-distortion via the computer unit, a pre-distortion is performed via optical elements arranged in front of the reflective surface.

8. The method according to claim 1, wherein in the calibration phase, a single set of pre-distortion parameters is determined independently of a current viewing position and/or a current viewing angle.

9. The method according to claim 1, wherein the display-related pre-distortion parameters are determined in the operating phase, as a function of the current viewing position and/or the current viewing angle.

10. The method according to claim 9, wherein a data base for determining the display-related pre-distortion parameters as a function of the current viewing position and/or the current viewing angle is determined in the calibration phase.

11. The method according to claim 10, wherein at least one of an actual position and an estimated position of the eye and/or a direction of gaze of a driver of the motor vehicle is measured continuously in the operating phase;

and a set of pre-distortion parameters suitable for the currently measured and/or estimated position of the eye and/or the direction of gaze is determined.

12. The method according to claim 9, wherein at least one of an actual position and an estimated position of the eye and/or a direction of gaze of a driver of the motor vehicle is measured continuously in the operating phase;

and a set of pre-distortion parameters suitable for the currently measured and/or estimated position of the eye and/or the direction of gaze is determined.

13. The method according to claim 1, wherein a data base for determining the display-related pre-distortion parameters as a function of the current viewing position and/or the current viewing angle is determined in the calibration phase.

14. The method according to claim 13, wherein at least one of an actual position and an estimated position of the eye and/or a direction of gaze of a driver of the motor vehicle is measured continuously in the operating phase;

and a set of pre-distortion parameters suitable for the currently measured and/or estimated position of the eye and/or the direction of gaze is determined.

15. The method according to claim 1, wherein computational operations that are carried out in the calibration phase are at least partially performed by an additional computer unit operatively coupled to the computer unit only in the calibration phase.

16. The method according to claim 15, wherein the computational operations comprise at least comparing the recorded image data with the original image data and/or determining a data base for determining display-related pre-distortion parameters as a function of a current viewing position and/or a current viewing angle.

17. A method of displaying image elements composed of computer-generated pixels reflected on a non-planar reflective surface in a motor vehicle, the method comprising the acts of:

in an operating phase of a display unit, calculating pre-distorted image data based on distortion characteristics of the non-planar reflective surface from original image data of the computer-generated pixels as a function of pre-distortion parameters of the display; and

transferring the pre-distorted image data to the display unit for projecting the image elements onto the non-planar reflective surface;

obtaining the pre-distortion parameters of the display by, in a calibration phase, projecting pre-distorted image data in the form of original image data using a same procedure as in the operating phase and recording at least two image data records for comparison with the original image data, wherein the at least two image data records are captured from at least one of different camera positions and different camera angles.

18. The method according to claim 17, wherein the pre-distortion parameters of the display are further determined in the operating phase as a function of at least one of a current viewing position and a current viewing angle of an operator.

19. The method according to claim 17, wherein a database for determining the pre-distortion parameters of the display as a function of at least one of a current viewing position and current viewing angle is determined in the calibration phase.