Method for Determining a Display Image

• US 20090015389A1
• Filed: 07/14/2008
• Published: 01/15/2009
• Est. Priority Date: 07/13/2007
• Status: Active Grant

• Current Assignee: Dr Ing hc F Porsche AG (Volkswagen AG)
• Original Assignee: Dr Ing hc F Porsche AG (Volkswagen AG)
• Inventors: Armand, Joerg, Schmelzer, Christian, Seehaus, Timo, Boehlendorf, Alexander
• Granted Patent: US 7,974,783 B2
• Time in Patent Office: Days
• US Class Current: 340/435
• CPC Class Codes: B60Q 9/007 providing information about the distance to an obstacle, e.g. varying sound
• CPC Class Codes: G06T 11/203 Drawing of straight lines or curves

Abstract

In order to determine an easily perceived display image for a driver assistance system, in particular a distance-measuring system or a parking assistant, a method makes use of the determination of Bezier curves on the basis of measured distance values on various measuring lines. Wherein different variants for the selection of the reference points and the curve edge points are available for the modeling and parameterization of the Bezier curves taking into account the respective current situation. It is also possible for object positions not to be taken into account under certain conditions in order to obtain smooth illustrative curves.

Claims

1. A method for determining a display image for a driver assistance system of a motor vehicle, from a plurality of measured distance values using at least one Bezier curve for representing sensed objects, which comprises the steps of:

assigning the measured distance values to individual measuring lines;

determining object positions of the sensed objects from given sensor positions, the individual measuring lines emanating from the given sensor positions and the measured distance values;

combining adjacent ones of the measuring lines on which the object positions lie to form groups;

defining object references points including a first and a second object reference point, each on one side of a respective one of the measuring lines and on a common orthogonal of the respective measuring line, for each measuring line on which an object position lies;

assigning each of the individual measuring lines a sensor measuring angle having limbs that intersect a measuring boundary line at sensor edge points; and

determining a respective Bezier curve for each of the groups, the respective Bezier curve running through the object positions and ending at curve sensor edge points forming two outer sensor edge points of a respective group, and reference points of the respective Bezier curve of the respective group are formed by the object reference points of the respective group.

2. The method according to claim 1, wherein if at least three of the object positions which are assigned to adjacent measuring lines lie on a straight line taking into account specific maximum deviations, each of the adjacent measuring lines is assigned a wall parameter, and it is checked whether the adjacent measuring lines are each assigned the wall parameter, and in that in this case the two object positions which are assigned to the corresponding measuring lines are connected to one another by a straight line or the object reference points which are assigned to the object positions are arranged directly on the respective measuring line.

3. The method according to claim 2, wherein if the wall parameter is set for an outer lateral sensing line, in order to determine the display image on an outside, an additional virtual side sensing line, which is assigned a virtual object position and a wall parameter, is generated as well as the outer lateral sensing line.

4. The method according to claim 3, wherein the wall parameter is also set for the measuring line adjacent to the outer lateral sensing line on an inside.

5. The method according to claim 2, wherein if the wall parameter is set for more than two immediately adjacent measuring lines, the two outer object positions for which the wall parameters are set are taken into account in a determination of the display image and at least one of the other object positions between the two outer object positions is not taken into account.

6. The method according to claim 1, wherein if a measured distance value of the measuring line is smaller than a measured distance value of the measuring line which is adjacent thereto and a difference exceeds a given threshold value, the measured distance value of the adjacent measuring line is removed, wherein a corresponding curve edge point remains unchanged.

7. The method according to claim 5, which further comprises restricting the application to the measuring lines with an exception of outer measuring lines.

8. The method according to claim 1, which further comprises defining the sensor measuring angle in dependence on the measured distance values.

9. The method according to claim 8, which further comprises defining the sensor measuring angles of two adjacent ones of the measuring lines for which the measured distance values are present in dependence on an absolute value of a difference between the measured distance values.

10. The method according to claim 9, which further comprises selecting the sensor measuring angles in direct proportion to the difference between the measured distance values.

11. The method according to claim 8, which further comprises defining a same values for all the sensor measuring angles.

12. The method according to claim 1, wherein for each of the measuring lines for which a measured distance value is present, a distance of the object reference points from the respective measuring line is determined in dependence on the measured distance values of the respective measuring line and the measuring line which is adjacent in a direction of the object reference point.

13. The method according to claim 12, wherein the distance of the object reference point from the respective measuring line is proportional to a difference between the distance values of the two adjacent measuring lines with a proportionality constant which is common to all the distances.

14. The method according to claim 1, wherein a position of the object reference points along the respective measuring line which is assigned to the respective measuring line is at a same height as the respectively object position.

15. The method according to claim 1, wherein when there is a group of the measuring lines, positions of the object reference points along the measuring lines which are assigned to the object reference points are approximated to one another on a basis of a height of the measured distance values.

16. The method according to claim 1, which further comprises determining the display image repeatedly, and when there are changes in the measured distance values between the display image which is present and a subsequent determination, only part of a difference from data of the display image which is present is taken into account in a determination.