Traffic monitoring device

• US 4,866,438 A
• Filed: 03/23/1988
• Issued: 09/12/1989
• Est. Priority Date: 04/11/1987
• Status: Expired due to Fees

• Current Assignee: Robot FOTO & Electronic GmbH & Company KG
• Original Assignee: Robot FOTO & Electronic GmbH & Company KG
• Inventors: Knisch, Konrad
• Primary Examiner(s): Crosland, Donnie L.
• Application Number:
  US07/172,022
• Time in Patent Office: 538 Days
• Field of Search: 340/936, 340/937, 346/107 VP, 346/33 D, 364/438, 358/107, 358/110, 358/125, 342/66, 342/190
• US Class Current: 340/936
• CPC Class Codes: G01S 13/92 for velocity measurement
• CPC Class Codes: G08G 1/054 photographing overspeeding vehicles

Abstract

With a traffic monitoring device for photographic recording of vehicles exceeding a predetermined speed, the speed of the approaching traffic is measured substantially against the travelling direction. The vehicles (12) are photographed frontally when they exceed the predetermined speed. Two speed measurements are effected: A first measuring value is obtained in a relatively short part of the available measuring section (22) on the entrance side and serves to release a camera (18). A second measuring value evaluates all speed measuring values occuring in the measuring section (22), in which the vehicle (12) is detected by the radar beam (20). This second measuring value is recorded.

Claims

1. Traffic monitoring device for photographic recording of vehicles exceeding a predetermined speed, wherein the speed of the vehicles is measured by Doppler radar substantially against the travelling direction and the vehicles are photographed frontally, comprising

(a) a radar transmitter (16), which emits a divergent radar beam (20) at a small angle to the longitudinal direction of the road, such that a measuring section (22), in which a vehicle (12) is detected by the radar beam (20), is defined on the road (10),

(b) a camera (18) having an aperture angle covering the measuring section (22) and adapted to produced a picture of a vehicle (12) in a way permitting identification of the license number of the vehicle,

(c) means for forming a measuring value of the speed of a vehicle from the radar signals reflected at the vehicle in a part (28) of the measuring section (22) where the vehicle is initially entering the measuring section (22),

(d) means for actuating the camera when said measuring value exceeds a predetermined threshold value, and

(e) speed recording means, characterized in that

(f) means are provided for forming a second measuring value of the speed of the vehicle (12) from a plurality of speed measuring values, which are obtained over the total measuring section (22) from the radar signals reflected at the vehicle (12), and

(g) the second measuring value of the speed is applied to the speed recording means.

2. Device as set forth in claim 1, characterized in that

(a) the camera (18) is a photographic camera having a film feedable picture by picture,

(b) the speed recording means comprise an arrangement of light emitting diodes, which are arranged in the area of the film rim and adapted to be controlled during the film feeding by memory means memorizing said second measuring value such that said second measuring value is digitally recorded on the film rim, and

(c) the speed recording means are adapted to be energized for recording of a speed only when said second measuring value exceeds a predetermined threshold value.

3. Device as set forth in claim 1, characterized in that

(a) means are provided for forming a histogram (84) from said plurality of speed measuring values, as well as

(b) means for establishing a frequency level (86), and

(c) means for analyzing the structure of the part of the histogram (84) exceeding the predetermined frequency level (86) for the purpose of distinction between evaluateable and non-evaluateable measurements.

4. Traffic monitoring device for photographic recording of vehicles exceeding a predetermined speed, wherein the speed of the vehicles is measured by Doppler radar substantially against the travelling direction and the vehicles are photographed frontally, comprising

(a) a radar transmitter (16), which emitts a divergent radar beam (20) at a small angle to the longitudinal direction of the road, such that a measuring section (22), in which a vehicle (12) is detected by the radar beam (20), is defined on the road (I0),

(b) a camera (18) having an aperture angle covering the measuring section (22) and adapted to produce a picture of a vehicle (12) in a way permitting identification of the license number of the vehicle,

(c) means for forming a measuring value of the speed of a vehicle from the radar signals reflected at the vehicle in a part (28) of the measuring section (22) where the vehicle is initially entering the measurement section (22),

(d) means for actuating the camera when said measuring value exceeds a predetermined threshold value, and

(e) speed recording means, characterized in that

(f) means are provided for forming a second measuring value of the speed of the vehicle (12) from a plurality of speed measuring values, which are obtained over the total measuring section (22) from the radar signals reflected at the vehicle (12), and

(g) the second measuring value of the speed is applied to the speed recording means,

(h) means are provided for forming a histogram (84) from said plurality of speed measuring values, as well as

(i) means for establishing a frequency level (86),

(j) means for analyzing the structure of the part of the histogram (84) exceeding the predetermined frequency level (86) for the purposes of distinction between evaluateable and non-evaluateable measurements,

(k) means for adding up all frequencies of the histogram (84) to form a frequency sum are provided,

(l) a limit value for the frequency sum is predetermined, frequency sums below the limit value being associated with a first type of vehicle (passenger cars) and frequency sums above the limit value being associated with a second type of vehicles (motor lorries), and

(m) a first threshold value for the measuring values of the speed is predetermined with a frequency sum below the limit value and a second threshold value for the measuring values of the speed is predetermined with a frequency sum above the limit value.

5. Device as set forth in claim 4, characterized in that a second upper limit value for the frequency sum is predetermined, frequency sums above this upper limit value being associated with a vehicle convoy and a thus obtained measuring value of the speed being not accepted.