Method of calibrating a sensor system

• US 6,778,928 B2
• Filed: 12/26/2000
• Issued: 08/17/2004
• Est. Priority Date: 12/24/1999
• Status: Expired due to Fees

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Stiller, Christoph
• Primary Examiner(s): Barlow, John
• Assistant Examiner(s): Sun, Xiuqin
• Application Number:
  US09/748,492
• Publication Number:
  US 20020072869A1
• Time in Patent Office: 1,330 Days
• Field of Search: 364/424.02, 364/474.35, 701/301, 701/300, 701/1, 701/200, 367/99, 702/104, 340/435
• US Class Current: 702/104
• CPC Class Codes: G01C 21/26 specially adapted for navigation in a road network
• CPC Class Codes: G01C 25/00 Manufacturing, calibrating, cleaning, or repairing instruments or devices referred to in the other groups of this subclass testing, calibrating or compensating compasses G01C17/38
• CPC Class Codes: G01S 13/867 Combination of radar systems with cameras
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 17/86 Combinations of lidar systems with systems other than lidar, radar or sonar, e.g. with direction finders
• CPC Class Codes: G01S 17/931 of land vehicles
• CPC Class Codes: G01S 2013/9323 Alternative operation using light waves
• CPC Class Codes: G01S 2013/9324 Alternative operation using ultrasonic waves
• CPC Class Codes: G01S 2013/93271 in the front of the vehicles
• CPC Class Codes: G01S 7/4004 of parts of a radar system
• CPC Class Codes: G01S 7/4052 by simulation of echoes
• CPC Class Codes: G01S 7/4091 during normal radar operation
• CPC Class Codes: G01S 7/497 Means for monitoring or calibrating
• CPC Class Codes: G06T 2207/10021 Stereoscopic video; Stereoscopic image sequence
• CPC Class Codes: G06T 2207/30252 Vehicle exterior; Vicinity of vehicle
• CPC Class Codes: G06T 7/85 Stereo camera calibration
• CPC Class Codes: G06V 20/56 exterior to a vehicle by using sensors mounted on the vehicle

Abstract

A method of calibrating a sensor system which is used to detect and analyze objects in the path of a vehicle is described. In this method, characteristic data of the objects is detected with the sensor system, and data interpreted as stationary or quasi-stationary objects, taking into account the vehicle'"'"'s own motion, is sent to a calibration unit. In the calibration unit, the deviation of the instantaneously measured data from data of a model of the objects is determined as the error vector and used for correcting the data of the model for the purpose of minimizing the deviation.

Claims

1. A method for calibrating a sensor system for detecting and analyzing an object in a path of a vehicle, comprising the steps of:

detecting characteristic data of the object by operating the sensor system;

sending to a calibration unit data that is interpreted as representing the object as one of stationary and quasi-stationary, taking into account a motion of the vehicle;

determining a deviation in instantaneously measured data from data of a model of the object as an error vector;

correcting, in accordance with the deviation, the data of the model in order to minimize the deviation;

after an initialization phase occurring in accordance with preselectable parameters, performing a first determination of object data stored as model data;

in all subsequent measurements performed cyclically, processing instantaneous data of the object data in the calibration unit with the previously determined and stored model data in order to obtain the respective error vector;

during the processing step, selecting the object data, any object data not found again being deleted and newly added object data being included; and

characterizing the object data including a reduction in a respective confidence interval after repeated measurements from different positions of the vehicle as data belonging to one of the stationary object and the quasi-stationary object.

2. The method according to claim 1, further comprising the steps of:

determining a congruent relative velocity of the object from successive ones of the object data;

determining the motion of the vehicle on the basis of the congruent relative velocity; and

characterizing the object data attributable to the object including the congruent relative velocity as data belonging to one of the stationary object and the quasi-stationary object.

3. The method according to claim 1, wherein:

a rotational motion of the vehicle due to at least one of a pitching motion and a turning a corner corresponds to the motion of the vehicle.

4. The method according to claim 1, further comprising the step of:

causing a sensor arranged in an image recording system of the sensor system to serially determine and analyze pixels in accordance with an electronic camera having a nonlinear transformer characteristic in a recording interval.

5. The method according claim 1, further comprising the step of:

transferring a result of a calibration of a sensor of the sensor system to at least one other sensor in the vehicle in order to calibrate the at least one other sensor.

6. The method according to claim 1, further comprising the step of:

sending a signal to one of an analyzer unit and a driver of the vehicle when at least one sensor of the sensor system yields contradictory measurement data.