Method and device for managing road traffic using a video camera as data source

• US 6,366,219 B1
• Filed: 11/19/1999
• Issued: 04/02/2002
• Est. Priority Date: 05/20/1997
• Status: Expired due to Fees

• Current Assignee: Bouchaib Hoummady
• Original Assignee: Bouchaib Hoummady
• Inventors: Hoummady, Bouchaib
• Primary Examiner(s): Tweel, John
• Application Number:
  US09/443,913
• Time in Patent Office: 865 Days
• Field of Search: 340/907, 340/916, 340/917, 340/934, 340/936, 340/937, 340/933, 701/117, 701/118
• US Class Current: 340/907
• CPC Class Codes: G08G 1/04 using optical or ultrasonic detectors
• CPC Class Codes: G08G 1/08 according to detected number or speed of vehicles

Abstract

An improved traffic management process and apparatus. After a camera gathers information, the system automatically extracts important information by image processing and analysis techniques. The system identifies all types of movement including pedestrians and two-wheel vehicles. The process and the apparatus first simulate and validate the strategy prior to its on-site implementation.

Claims

1. A road traffic management process comprising:

acquiring information in the form of video images with a camera,

extracting a part of the information by image processing and controlling three-color traffic lights by taking into account said information,

simulating step strategies for regulating the states of the three-color traffic lights,

evaluating the best regulation strategy, and transferring the programs for the three-color traffic lights corresponding to the best strategy selected.

2. The process according to claim 1, characterized in that it includes one or more cameras as an information source and automates extraction of the useful information by image processing and analysis techniques performed on the video images of the traffic and circulation, according to which on the basis of the information automatically extracted from the video images, the following is performed on decisional zones in an intersection

automatic measuring of decisional magnitudes from the detection and extraction of the movements in the traffic circulation,

automatic diagnosis of the operation of the regulation and its deficiencies based on these zones and magnitudes,

remote control, according to decisional logic, of the three-color traffic lights by automatically taking into account the spatiotemporal decisional information, magnitudes and measurements in the decisional zones,

automatic monitoring of the events and their origins which could be of interest in the decisional zones using the thresholds that can be parameterized on the magnitudes.

3. The process according to claim 1, further comprising:

digitizing the video image to obtain a digitized image and extracting from the digitized image the set of zones in movement in the analyzed scene by spatiotemporal comparison of characteristics corresponding to the objects in movement in the images, and

representing, in a first phase, movement by the surfaces encompassing the identified objects and in a second phase “

the recent past”

corresponds to the various surfaces covered successively in time by the moving objects by calculation of the various spatiotemporal coverages in the surfaces presently covered and encompassing the identified objects.

4. The process according to claim 1, characterized in that it recalculates as needed on decisional zones in an intersection that can be parameterized and from surfaces of identified moving objects in the processed images the decisional measurements of punctual and spatiotemporal traffic.

5. The process according to claim 1, characterized in that it:

simulates the regulation strategies, road circulation and changes in the states of the three-color traffic-lights of the site using previously extracted decisional measurements,

evaluates the best strategy corresponding to the regulation site by comparison and recalculation of the measurements given by each of the strategies,

transfers to a controller (E1) the programs for the three-color traffic-lights and the conditions for changing the states corresponding to the strategy developed and selected for the objective to be attained by the manager of the regulation and road circulation such as;

optimization of an intersection with three-color traffic lights with fixed cycles, adaptivity in relation to conflict sites, gridlock prevention, traffic jam prevention, adaptivity in relation to the saturation rate, the fluidity-safety, adaptivity in relation to directional movements, adaptivity in relation to pedestrian crossing time, optimization of time wasted in front of the three-color traffic lights, adaptivity in relation to road work sites.

6. The process according to claim 1, further comprising assigning decisional thresholds to selected measures, said decisional thresholds being values corresponding to extreme limits to be taken into account in the decision logic.

7. The process according to claim 1, characterized in that decisional zones in an intersection with regard to identification or measurement or regulation or monitoring in the circulation site are not fixed and correspond to a site of interest selected from the group consisting of the entries to an intersection or traffic circle, the exits, the waiting lines at the entries, the waiting lines at the exits, the left turns, the center of the intersection, the occasional parking zones, the pedestrian passages, the cycle zones, the pedestrian zones, the entrances-exits of public or private institutions, and public or private places.

8. The process according to claim 1, characterized in that the process uses decisional magnitudes and measurements which are:

the flow rate, the saturation flow rate, the vehicle interval, the linear density, the punctual coverage rate, the apparent speed, the concentration, the spatial coverage rate, the spatiotemporal coverage rate, the spatial release rate, the spatial fluidity rate, the spatial saturation rate, the stopping time, the average release time, the waiting line length, the average waiting time, the directional flow rate, the crossing time and any other measurements composed of the cited measurements.

9. The process according to claim 1, characterized in that the process uses decision logic which is composed of:

comparison operators (AND, OR, MAXIMUM, MINIMUM, GREATER THAN, LESS THAN, PRESENCE, ABSENCE, etc.) on the decisional measurements in the zones of interest,

condition operators (IF, IF NOT, etc.),

action operators (CLOSE, OPEN, TURN ON LIGHT, TURN OFF LIGHT, SLOW DOWN, POSITION, STOP, RELEASE, INFORM, etc.) on the interfaces and action material equipment for measurement, regulation and monitoring.

10. The process according to claim 1, characterized in that the regulation strategy includes regulation of traffic circulation which comprises:

in a first initialization step;

definition of the decisional zones in the video images of the regulation site,

definition of the decisional magnitudes and measurements by zone,

establishment of optimal strategy corresponding to the regulation of the site,

establishment of the programs for the three-color traffic lights corresponding to the optimal regulation strategy,

definition of the decisional logic by zone,—

in a second repetitive operating step;

extraction from the video images from the cameras (1) of the corresponding moving surfaces,

calculation of the decisional measurements in the programmed zones,

execution of the decisional logic,

activation according to the decisional logic of the intersection controller (E1),

execution of the program for the three-color traffic lights corresponding to the result of the decisional logic.

11. The process according to claim 1, characterized in that the process identifies a number of decisional zones which can reach at least 200.

12. The process according to claim 1, characterized in that the process includes automatic event monitoring which comprises:

a parameterization step characterizing, by the magnitudes and a decisional logic, an event in each programmed zone,

a second repetitive step

extraction from the video images from the cameras of the corresponding moving surfaces,

temporary storage in a buffer memory of the digitized images of a video sequence of a duration that can be parameterized such that each new image introduced into the buffer memory replaces the oldest image,

automatic identification of the events with storage of a video sequence containing the last seconds before detection of the event and several seconds afterwards,

remote transfer in the case of identification of the images of events,—

signaling of an alarm, in the case of identification of an event, to the connected devices.

13. A global or partial road traffic management system (measurement, regulation, monitoring) by video camera formed of an assembly of interconnected electronic equipment for the implementation of the process according to claim 1, comprising:

a first assembly of equipment (E1) installed in a cabinet of the three color traffic light which comprises an arithmetic and logical unit card, the function of which is to execute the regulation strategy defined from the control keyboard, an input/output card for communication with the second part of the device installed in the central station for receiving new regulation strategies, three-color traffic light control cards, a power card, a sensor input-output card, a telephone communication device, video inputs, video outputs, an image-processing logical unit,

an assembly of equipment (E4) installed at the central station of the streets department constituted by a central unit, a video input, an image digitization card, a storage unit, a control keyboard.

14. The system according to claim 13, characterized in that it controls said assembly of equipment (E4) for recalculation on request on decisional zones in an intersection that can be parameterized of the punctual and spatiotemporal traffic measurements.

15. The system according to claim 13, characterized in that it controls a simulation unit for simulation of a strategy for regulation, road circulation and changes in the three-color traffic light signaling states in an intersection using previously extracted measurements and transfers the programs for the three color traffic light and the conditions of the state changes corresponding to the strategy developed and selected to first assembly (E1).

16. Apparatus (E2) installed on site in regulation cabinets of the three-color traffic lights for the implementation of the process according to claim 1, characterized in that it automatically extracts the useful information in the video images, controls a controller (E1) and an assembly (E3) and remotely controls controller (E1) relative to decisional zones in an intersection, decisional magnitudes, decisional thresholds assigned to each decisional magnitude and the logic for the control system corresponding to the decisional limits and thresholds reached.

17. The system according to claim 13, characterized in that it is controlled by an assembly of equipment (E3), stores certain events in memory, identifies when said stored events occur, and controls the assembly (E3) for the transfer of said video outputs which occur at the beginning of said events.

18. Apparatus (E2) installed on site in regulation cabinets of the three-color traffic lights for the implementation of the process according to claim 1, characterized in that it extracts from a digitized image a set of zones in movement in the analyzed scene and represents in a first phase the movement by the surfaces encompassing objects identified as moving in the analyzed scene and in a second phase “

the recent past”

corresponds to the various surfaces occupied successively over time by the moving objects by the calculation of the various spatiotemporal occupancies in the surfaces presently occupied and encompassing the identified objects which will be stored in a backup unit.

19. Apparatus for implementation of the process according to claim 1 installed on site in regulation cabinets of the three-color traffic lights controlled by an assembly of equipment (E4) by means of a keyboard for specifying critical zones, for selecting the measurements and thresholds intervening in the decision, for identifying associated with the site and for detailing the objects and relevant factors to be monitored for their parameterization and controlled by (E2) for storage in the memory of a storage unit not corresponding to a video cassette solely the recent past and the beginning of each event in relation to the object of the monitoring such as:

prohibited parking, incident detection, detection of the crossing of continuous lines, stops and red three-color traffic lights, detection of waiting pedestrians, detection of vehicles going in the opposite direction, detection of the formation of waiting lines, detection of the formation of saturation, detection of the origin of pollution, detection of the origin of noise or collision, detection of graffitists, detection of the origin of saturation in the intersection direction, detection of regulation irregularities.