Arrangement and method for simultaneous measurement of the speed as well as the surface shape of moving objects

• US 6,614,536 B1
• Filed: 05/01/2000
• Issued: 09/02/2003
• Est. Priority Date: 04/30/1999
• Status: Active Grant

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Stockmann, Michael, Doemens, Guenter
• Primary Examiner(s): Smith, Zandra V.
• Application Number:
  US09/562,373
• Time in Patent Office: 1,219 Days
• Field of Search: 356/4.01, 356/601, 356/72, 356/28
• US Class Current: 356/601
• CPC Class Codes: G01S 17/58 Velocity or trajectory determination systems; Sense-of-movement determination systems
• CPC Class Codes: G01S 17/89 for mapping or imaging
• CPC Class Codes: G01S 7/4802 using analysis of echo signal for target characterisation; Target signature; Target cross-section
• CPC Class Codes: G08G 1/015 with provision for distinguishing between two or more types of vehicles, e.g. between motor-cars and cycles
• CPC Class Codes: G08G 1/04 using optical or ultrasonic detectors

Abstract

Surface shape determination and an exact speed measurement of a moving object is undertaken with an arrangement including semiconductor elements and having two spaced semiconductor sensor lines. Illumination of the moving object occurs via at least one laser diode that is arranged in the proximity of the semiconductor sensor lines. The semiconductor sensor lines are used to perform a registration of cross-sectional profiles by integrating a number of range vectors calculated from sensed reflected light pulses at times when the moving object is not present and present. Successively registered cross-sectional profiles of a vehicle are converted into cross-sectional areas and into longitudinal profiles. The speed can be identified on the basis of the time-offset between identical registration in the first and second semiconductor sensor lines. A categorization of different types of moving object is accomplished by comparing the calculated cross-sectional areas and longitudinal profiles with known object characteristics.

Claims

1. An arrangement for measuring at least one of a speed and a surface shape of moving objects based on measurements of travel time and intensity of light emitted from a light source and reflected by the moving objects, comprising:

at least one light source configured to illuminate moving objects with light pulses;

at least two optical semiconductor sensor lines positioned in a region of the at least one light source, the at least two optical semiconductor lines each being comprised of a plurality of sensor elements for sensing light emitted from the at least one light source that is reflected by the moving objects and a moving objects background across which the moving objects travel, the at least two optical semiconductor sensor lines being spaced a predetermined distance relative to one another and disposed parallel to one another, and arranged transverse to a travel direction of the moving objects; and

a controller for calculating range profiles of the moving objects based on measured travel time and intensity of light emitted from the at least one light source and reflected by at least one of the moving objects and the moving object background, and for deriving a surface shape of the moving objects based on the calculated range profiles.

2. The arrangement of claim 1, wherein individual sensor elements of the at least two optical semiconductor sensor lines are randomly accessed.

3. The arrangement of claim 1, wherein the at least two optical semiconductor sensor lines are CMOS components and the controller determines distance values of the moving objects using light propagation delay measurements.

4. The arrangement of claim 1, wherein the at least one light source is comprised of a modulating laser diode.

5. The arrangement of claim 1, wherein the at least one light source is comprised of a plurality of light sources and wherein each of the plurality of light sources respectively illuminates a portion of the moving objects.

6. The arrangement of claim 1, wherein the at least two optical semiconductor sensor lines are arranged perpendicular to the travel direction of the moving objects.

7. The arrangement of claim 1, wherein the at least two optical semiconductor sensor lines are arranged above the moving objects.

8. The arrangement of claim 1, wherein the at least two optical semiconductor sensor lines are arranged lateral to the moving objects.

9. The arrangement of claim 1, wherein respective coverage areas of the at least two optical semiconductor sensor lines are spaced approximately one meter apart.

10. The arrangement of claim 1, wherein corresponding coverage area of each of the at least two optical semiconductor sensor lines covers an entire width of a travel lane in which the moving objects travel.

11. The arrangement of claim 1, wherein the at least one light source is configured to illuminate a line on the moving object background having a width in the range of one to two centimeters.

12. The arrangement of claim 1, wherein the measured duration of light emitted from the at least one light source and reflected by at least one of the moving objects and moving objects background to the plurality of sensor elements include measuring at least one of a light pulse duration, short-time integrations and phase.

13. The arrangement of claim 12, wherein each of the plurality of sensor elements is comprised of two electrically separated element areas having light sensitive surfaces that are meshed with one another in order to accomplish short-time integration.

14. The arrangement of claim 1, wherein the speed and surface shape of a vehicle is determined.

15. The arrangement of claim 1, wherein the controller is configured to determine the surface shape of the moving object by including comparing a first calculated range profile of the moving object background where no moving object is present to at least one subsequently calculated range profile of the moving object as the moving object travels across the moving object background and determining at least one cross-sectional profile based on a difference between the first calculated range profile and at least one subsequently calculated range profile.

16. A method for determining at least one of speed and surface shape of moving objects based on measurements of the travel time of light emitted from a light source and reflected by the moving objects, comprising the steps of:

emitting at least one light pulse from at least one light source;

sensing light of the at least one light pulse that is reflected from one of a moving object or a moving object background across which the moving object travels using at least two optical semiconductor sensor lines positioned in a region of the at least one light source, the at least two optical semiconductor lines each being comprised of a plurality of sensor elements;

measuring travel time and intensity of light emitted from the at least one light source and reflected by at least one of the moving objects and the moving object background;

calculating range profiles of the at least one moving object based on measured travel time and intensity of light emitted from the at least one light source and reflected by at least one of the moving objects and the moving object background; and

comparing a first calculated range profile of the moving object background where no moving object is present to at least one subsequently calculated range profile of the moving object as it travels across the moving object background and determining at least one cross-sectional profile based on a difference between the first calculated range profile and at least one subsequently calculated range profile.

17. The method according to claim 16, wherein an area of a corresponding cross-section is determined by integration of the cross-sectional profile.

18. The method according to claim 17, wherein the integration of the cross-sectional profile includes summing all of the respective differences between the first calculated range profile and the at least one subsequently calculated range profile of the moving object as the moving object travels across the moving object background.

19. The method according to claim 17, wherein a longitudinal profile of the moving object is determined based on a sequence of a plurality of determined cross-sectional areas.

20. The method according to claim 17, further comprising the steps of:

determining a shape of the moving object based on a plurality of determined cross-sectional profiles and a longitudinal profile; and

classifying the moving objects into at least one of a plurality of categories based on the determined shape.

21. The method according to claim 20, wherein the plurality of categories includes a person, a motorcycle, a passenger vehicle and a truck.

22. The method according to claim 16, wherein two different short-time integrations having respective different integration times are implemented to a same object location for measuring the travel time of the light.

23. The method according to claim 22, wherein the two different short-time integrations occur for a same surface area on the basis of one of two interlocking element areas of each corresponding sensor element.

24. An arrangement for measuring at least one of a speed and a surface shape of moving objects based on measurements of travel time and intensity of light emitted from a light source and reflected by the moving objects, comprising:

at least one light source configured to illuminate moving objects with light pulses;

at least two optical semiconductor sensor lines positioned in a region of the at least one light source, the at least two optical semiconductor lines each being comprised of a plurality of sensor elements for sensing light emitted from the at least one light source that is reflected by the moving objects and a moving objects background across which the moving objects travel, the at least two optical semiconductor sensor lines being spaced a predetermined distance relative to one another and disposed parallel to one another, and arranged transverse to a travel direction of the moving objects; and

a controller for calculating range profiles of the moving objects based on measured travel time and intensity of light emitted from the at least one light source and reflected by the moving objects, and for deriving a surface shape of the moving objects based on the calculated range profiles.