DEVICE FOR PHOTOGRAPHIC MONITORING OF ROAD INTERSECTIONS CONTROLLED BY A TRAFFIC LIGHT

• US 3,858,223 A
• Filed: 01/24/1974
• Issued: 12/31/1974
• Est. Priority Date: 02/14/1973
• Status: Expired due to Term

• Current Assignee: Jurgen Holzapfel
• Original Assignee: Jurgen Holzapfel
• Inventors: Holzapfel, Jurgen
• Primary Examiner(s): Hartary, Joseph W.
• Application Number:
  US05/436,036
• Time in Patent Office: 341 Days
• Field of Search: 346/17UP,40 340/31C 354/76,105,106,354
• US Class Current: 396/263
• CPC Class Codes: G08G 1/0175 by photographing vehicles, e.g. when violating traffic rules

Abstract

At an intersection controlled by a traffic light, a first sensor provides an electric signal when a vehicle enters the intersection against the red light. That electric signal causes a first photograph to be immediately taken of the intersection and a second photograph of the intersection to be taken after a time delay. If that vehicle illegally entering the intersection turns right, it activates a second sensor which sends a signal to cause another picture to be taken. A second vehicle illegally entering behind the first will not interrupt the sequence of pictures initiated by the first, but will result in another picture being taken after a predetermined time lapse.

Claims

1. An improvement for an apparatus for photographically monitoring an intersection of two roads, at which there is a traffic light, by making photographs of vehicles entering the intersection against the stop signal of the traffic light, said apparatus including a first sensor positioned along one of the roads to produce a signal when a vehicle passes the first sensor, a first device to produce a first camera-actuating pulse in response to said signal for taking an initial photograph, and a second device to produce a second camera-actuating pulse a predetermined delay time after said initial photograph for taking a second photograph, said improvement comprising:

a second sensor positioned along the other of the two roads to produce a signal when a vehicle passes the second sensor; and

means connected to said second sensor and to said apparatus for producing a camera-actuating pulse when a signal from the second sensor occurs within said given period of time after the signal from the first sensor.

2. An apparatus and improvement as set forth in claim 1, wherein said second device comprises means defining a control path for said second camera-actuating pulse and including a first gate means, and said first device comprises a first monostable multivibrator triggered by the signal from the first sensor and connected to said first gate means to open the gate means for the passage of said second pulse.

3. An apparatus and improvement as set forth in claim 2, wherein said first multivibrator changes from its stable to its metastable state by said triggering, remains in its metastable state for said predetermined period of time and then returns to its stable state;

and said means defining said control path being connected to said first multivibrator to produce said second camera-actuating signal upon said multivibrator returning to its stable state.

4. An apparatus and improvement as set forth in claim 2, wherein said first sensor comprises an induction loop;

including a detection circuit connected to the first sensor for producing a detection pulse in response to the signal from the first sensor which detection pulse has a duration of at least the time required by the vehicle to pass the first sensor; and

wherein said first device comprises a second monostable multivibrator which remains in its metastable state for a shorter period of time than the duration of said detection pulse, means connecting said second multivibrator to said detection circuit to trigger the second multivibrator from its stable state to its metastable state by the initiation of said detection pulse, and means connecting said second multivibrator to the first multivibrator to normally trigger the latter when the second multivibrator returns to its stable state.

5. An apparatus and improvement as set forth in claim 4, wherein said first device includes a third monostable multivibrator having an input and an output, said second multivibrator being connected to said input whereupon the third multivibrator produces a pulse signal at its output in response to a signal at its input, means connecting said output of said third multivibrator to the first multivibrator to trigger the latter by the rear edge of said output pulse signal, and means connected to said output of said third multivibrator to use said output pulse signal to form said first camera-actuating pulse.

6. An apparatus and improvement as set forth in claim 5, wherein said means defining said control paths for said camera-actuating pulses includes second gate means;

and wherein said second device includes a fourth monostable multivibrator having an input and an output, means connecting the input of the fourth multivibrAtor to the first multivibrator to trigger the former by the latter returning to its stable state to thereby produce a signal at the output of the fourth multivibrator for forming said second camera-actuating pulse, a fifth monostable multivibrator having a metastable state duration substantially equal to the film feed time, means connecting said fifth multivibrator to the fourth multivibrator to be triggered by the rear edge of said output signal of the fourth multivibrator, and means connecting the second gate means to said fifth multivibrator to close said second gate means when the fifth multivibrator is in its metastable state to thereby prevent a camera-actuating pulse from being formed during the film feed time following said production of said signal at the output of the fourth multivibrator.

7. An apparatus and improvement as set forth in claim 6 including:

means connected to the first, third, fourth and fifth multivibrators and defining a third gate means connected between the second and third multivibrators for blocking signal passage between the latter during signal passage through said first, third, fourth and fifth multivibrators;

fourth gate means connected to said first device which is open and permits a signal to pass therethrough to produce a detection pulse when said third gate means is blocking, a pulse delaying sixth monostable multivibrator connected to said third gate means to delay said passed signal; and

a seventh monostable multivibrator connected to said sixth multivibrator for producing a camera-actuating pulse in response to said delayed passed signal.

8. An apparatus and improvement as set forth in claim 1, wherein said second sensor is positioned on said second road and to the right of said first road from said first sensor.