DEVICE AND METHOD TO DETECT AN OBJECT IN A GIVEN AREA, ESPECIALLY VEHICLES, FOR THE PURPOSE OF TRAFFIC CONTROL

• US 20010040514A1
• Filed: 08/26/1999
• Published: 11/15/2001
• Est. Priority Date: 02/27/1997
• Status: Active Grant

• Current Assignee: Ernst Horber
• Original Assignee: Ernst Horber
• Inventors: HORBER, ERNST
• Granted Patent: US 6,411,221 B2
• Time in Patent Office: Days
• US Class Current: 340/933
• CPC Class Codes: G01S 17/04 Systems determining the presence of a target
• CPC Class Codes: G01S 17/58 Velocity or trajectory determination systems; Sense-of-movement determination systems
• CPC Class Codes: G01S 7/4802 using analysis of echo signal for target characterisation; Target signature; Target cross-section
• CPC Class Codes: G08G 1/01 Detecting movement of traffic to be counted or controlled G08G1/07 - G08G1/14 take precedence

Abstract

When detecting an object in a given area, especially vehicles for the purposes of traffic control, there appear to be inaccuracies in the system based on measuring pulse propagation times. In order to avoid such inaccuracies, a sample of observed (measured) real values is compared with a gauging table having a sample of values stored therein, so that pulse propagation time measurements are no longer necessary.

Claims

1. Apparatus for detecting an object in a predetermined spatial region, in particular vehicles for traffic monitoring, including

at least one transmitter (10) for generating and emitting radiation pulses to the predetermined spatial region,

at least one receiver (12) which receives the radiation backscattered or reflected from the predetermined spatial region and emits a detection signal (U(t)) as a function of backscattered or reflected radiation,

at least two devices (15) for the detection of instantaneous values (Ui) of the detection signal U(t) within corresponding time intervals,

a control device (14) which emits a control signal to the transmitter (10) to trigger the emission of a radiation pulse, and to the device (15) for the detection of instantaneous values for fixing the time intervals for detection of the instantaneous values, and

a device (16, 17, 18) for comparison of a value pattern that can be derived from the detected instantaneous values, with stored value patterns.

2. Apparatus according to

claim 1

, wherein the detection signal U(t) is fed in parallel to the at least two devices (15) for the detection of instantaneous values.

3. Apparatus according to

claim 1

, wherein the devices (15) for the detection of instantaneous values are instantaneous voltage measuring devices (15;

15-1, 15-2, 15-n).

4. Apparatus according to

claim 3

, wherein each instantaneous voltage measuring device (15) includes a switch (15a) which is open in the untriggered state and which is operated by the control pulse from the control device (14), and an integrating amplifier (15b) to which the detection signal U(t) is fed when the switch (15a) is closed.

5. Apparatus according to

claim 1

, including a device (16) for digitalization of the detected instantaneous values and an evaluating device (17) for deriving a value pattern from the instantaneous values and for comparison of the value pattern with stored value patterns.

6. Apparatus according to

claim 5

, wherein the stored value patterns are filed in a calibration table.

7. Apparatus according to

claim 6

, wherein the value patterns filed in the calibration table are assigned to given distances.

8. Apparatus according to

claim 1

, wherein the radiation pulse radiated by the transmitter (10) is narrowly focused for the distance measurement or wherein the radiation pulse radiated by the transmitter (10) is fanned out for space monitoring.

9. Apparatus according to

claim 1

, wherein the radiation pulse is a laser light pulse, preferably with a wavelength of about 860 nm.

10. Apparatus according to

claim 9

, wherein the full width at half-maximum of the pulse is about 15 ns.

11. Apparatus according to

claim 9

, wherein the repetition rate of the pulse is about 30 kHz.

12. Method for detecting an object in a predetermined spatial region, in particular vehicles for traffic monitoring, with the steps of:

emitting at least one radiation pulse to the predetermined spatial region,

receiving the radiation backscattered or reflected from the predetermined spatial region,

generating a detection signal as a function of the radiation backscattered or reflected from the predetermined spatial region,

detecting instantaneous values of the detection signal within at least two measurement time intervals,

deriving a value pattern from the detected instantaneous values and

comparison of the value pattern with stored value patterns.

13. Method according to

claim 12

, wherein the comparison of the value pattern is carried out with the aid of value patterns stored in a calibration table.

14. Method according to

claim 13

, wherein the comparison leads to a distance filed in the calibration table as the result.

15. Method according to

claim 12

, wherein the measurement time intervals almost completely cover a predetermined measurement time range in which the backscattered or reflected radiation is received.

16. Method according to

claim 12

, wherein the width of a measurement time interval does not exceed the pulse width of the received backscattered or reflected radiation.

17. Method according to

claim 12

, wherein each received pulse is capable of detection in at least two measurement intervals offset from each other in time.

18. Method according to

claim 12

, wherein the instantaneous values are instantaneous voltage values.

19. Method according to

claim 12

, wherein the radiation pulse is a laser light pulse, preferably with a wavelength of about 860 nm.

20. Method according to

claim 19

, wherein the full width at half-maximum of the pulse is about 15 ns.

21. Method according to

claim 19

, wherein the repetition rate of the pulse is about 30 kHz.