Method and apparatus for traffic light violation prediction and control

Abstract

A traffic sensor system for detecting and tracking vehicles is described. The disclosed system may be employed as a traffic light violation prediction system for a traffic signal, and as a collision avoidance system. A video camera is employed to obtain a video image of a section of a roadway. Motion is detected through changes in luminance and edges in frames of the video image. Predetermined sets of pixels (“tiles”) in the frames are designated to be in either an “active” state or an “inactive” state. A tile becomes active when the luminance or edge values of the pixels of the tile differ from the respective luminance or edge values of a corresponding tile in a reference frame in accordance with predetermined criteria. The tile becomes inactive when the luminance or edge values of the pixels of the tile do not differ from the corresponding reference frame tile in accordance with the predetermined criteria. Shape and motion of groups of active tiles (“quanta”) are analyzed with software and a neural network to detect and track vehicles.

What is claimed is:  
     
         1 . A traffic light violation prediction system for a traffic signal having a at least a red phase and a green phase, comprising: 
 at least one image capturing device, said image capturing device operative to provide image data of at least one vehicle approaching said traffic signal; and    a computation unit, operative in response to said image capturing device and an indication of said current traffic light phase, to determine whether said at least one vehicle approaching said traffic signal will violate a red light phase of said traffic signal.    
     
     
         2 . The system of  claim 1 , wherein said image capturing device comprises at least one video camera.  
     
     
         3 . The system of  claim 1 , wherein said traffic signal has a yellow light phase, and said computation unit is further responsive to a time remaining in said yellow light phase.  
     
     
         4 . The system of  claim 1 , wherein said computation unit is further responsive to a current speed of said at least one vehicle approaching said traffic intersection.  
     
     
         5 . The system of  claim 1 , wherein said computation unit is further responsive to a current acceleration of said at least one vehicle approaching said traffic intersection.  
     
     
         6 . The system of  claim 1 , wherein said computation unit is further responsive to a current position of said at least one vehicle approaching said traffic intersection.  
     
     
         7 . The system of  claim 1 , wherein said computation unit is further operable to compute a time remaining before said at least one vehicle approaching said traffic intersection enters said traffic intersection, responsive to a determination of a current acceleration of said vehicle.  
     
     
         8 . The system of  claim 7 , wherein said computation unit is further operable to calculate a rate of deceleration required for said at least one vehicle to stop within said time remaining before said vehicle enters said traffic intersection.  
     
     
         9 . A method for predicting a traffic light violation of a traffic signal having at least a red phase and a green phase, comprising: 
 providing image data showing at least one vehicle approaching said traffic signal; and    determining, responsive to said image data and an indication of a current traffic light phase, whether said at least one vehicle approaching said traffic signal will violate a red light phase of said traffic signal.    
     
     
         10 . The method of  claim 9 , wherein said image data is generated by at least one video camera.  
     
     
         11 . The method of  claim 9 , wherein said determining is performed by a computation unit comprising software executing on a processor.  
     
     
         12 . The method of  claim 9 , wherein said traffic light further includes a yellow phase, and wherein said determining is further responsive to a time remaining in said yellow phase.  
     
     
         13 . The method of  claim 9 , wherein said determining further includes the step of determining a current speed for said at least one vehicle approaching said traffic intersection.  
     
     
         14 . The method of  claim 9 , wherein said determining further includes the step of determining a current acceleration for said vehicle approaching said traffic intersection.  
     
     
         15 . The method of  claim 14 , wherein said determining further includes computing a time remaining before said vehicle approaching said traffic intersection enters said traffic intersection, responsive to said determination of said current acceleration of said vehicle.  
     
     
         16 . The method of  claim 15 , further comprising calculating, by said computation unit, a deceleration required for said vehicle to stop within said time remaining before said vehicle enters said traffic intersection.  
     
     
         17 . A collision avoidance system for a first traffic signal having a current light phase equal to one of a red light phase and a green light phase, and a second traffic signal having a current light phase equal to one of a red light phase and a green light phase, comprising: 
 at least one image capturing device, for capturing a plurality of images;    said plurality of images showing at least one vehicle approaching said first traffic signal;    a computation unit, responsive to said plurality of images and an indication of said current first traffic signal light phase, for determining whether said at least one vehicle approaching said first traffic signal will violate said red light phase of said first traffic signal, and for delaying an upcoming green traffic light phase of said second traffic signal responsive to a determination that said at least one vehicle approaching said first traffic signal will violate a red phase of said first traffic signal.    
     
     
         18 . The system of  claim 17 , wherein said image capturing device comprises at least one video camera.  
     
     
         19 . The system of  claim 17 , wherein said computation unit comprises software executing on a processor.  
     
     
         20 . The system of  claim 17 , wherein said computation unit is further responsive to a time remaining in yellow light phase input.  
     
     
         21 . The system of  claim 17 , wherein said computation unit is further operable to determine a current speed for said at least one vehicle.  
     
     
         22 . The system of  claim 1 , wherein said computation unit is further operable to determine a current acceleration for said at least one vehicle.  
     
     
         23 . The system of  claim 17 , wherein said computation unit is further operable to compute a time remaining before one of said at least one vehicle enters said traffic intersection, responsive to determination of a current acceleration of said vehicle.  
     
     
         24 . The system of  claim 23 , wherein said computation unit is further operable to calculate a deceleration required for said at least one vehicle to stop within said time remaining before said vehicle enters said traffic intersection.  
     
     
         25 . A method of collision avoidance for a first traffic signal having a current light phase equal to one of the set including at least red and green and a second traffic signal having a current light phase equal to one of the set including at least red and green, comprising: 
 capturing a plurality of images, said images showing at least one vehicle approaching said first traffic signal, said images derived from an output of a violation prediction image capturing device;    determining, responsive to said plurality of images and indication of said current first traffic signal light phase, whether said at least one vehicle approaching said first traffic signal will violate a red light phase of said first traffic signal; and    delaying an upcoming green light phase of said second traffic signal for a programmed time period responsive to a determination that said at least one vehicle approaching said first traffic signal will violate said red light phase of said first traffic signal.    
     
     
         26 . The method of  claim 25 , wherein said violation prediction image capturing device comprises at least one video camera.  
     
     
         27 . The method of  claim 25 , wherein said collision avoidance unit comprises software executing on a processor.  
     
     
         28 . The method of  claim 25 , further comprising: 
 determining at least one vehicle location associated with said at least one vehicle; and    wherein said determining whether said at least one vehicle will violate said red light phase of said first traffic signal is responsive to said at least one vehicle location.    
     
     
         29 . The method of  claim 25 , further comprising: 
 determining a time remaining in a current yellow light phase; and    wherein said determining whether said at least one vehicle will violate said red light phase of said first traffic signal is responsive to said time remaining in said current yellow light phase.    
     
     
         30 . The method of  claim 25 , further comprising: 
 determining a current speed for said at least one vehicle; and    wherein said determining whether said at least one vehicle will violate said red light phase of said first traffic signal is responsive to said current speed of said at least one vehicle.    
     
     
         31 . The method of  claim 25 , wherein said determining whether said at least one vehicle will violate said red light phase of said first traffic signal further comprises determining a current acceleration for said at least one vehicle.  
     
     
         32 . The method of  claim 25 , wherein said determining whether said at least one vehicle will violate said red light phase of said first traffic signal further comprises computing a time remaining before said at least one vehicle enters said traffic intersection.  
     
     
         33 . The method of  claim 32 , wherein said determining whether said at least one vehicle will violate said red light phase of said first traffic signal further comprises calculating a rate of deceleration required for said at least one vehicle to stop within said time remaining before said vehicle enters said traffic intersection.  
     
     
         34 . The method of  claim 33 , wherein said determining whether said at least one vehicle will violate said red light phase of said first traffic signal further comprises determining whether said required deceleration is larger than a specified deceleration limit value.  
     
     
         35 . An apparatus for facilitating operation of a traffic light at an intersection of first and second roadways, comprising: 
 at least one camera that provides first and second video frames that are representative of a field of view of said camera at different points in time;    a video processing circuit that detects vehicles; and    a processor circuit that determines vehicle position in the first and second video frames and vehicle velocity from the difference in vehicle position, said processor circuit being operative to delay the operation of said traffic light in response to predetermined conditions associated with said first and second video frames.    
     
     
         36 . An apparatus for facilitating operation of a traffic light at an intersection of first and second roadways, comprising: 
 at least one camera that provides first and second video frames that are representative of a field of view of said camera at different points in time;    a video processing circuit that detects vehicles; and    a processor circuit that determines vehicle position in the first and second video frames and vehicle velocity from the difference in vehicle position, said processor circuit being operative to generate a signal indicating that a vehicle is about to pass through said intersection in violation of a red-light.    
     
     
         37 . A method for controlling vehicular traffic at an intersection having a first traffic light for controlling traffic approaching said intersection from a first direction and a second traffic light for controlling traffic approaching said intersection from a second direction, wherein each of said traffic lights includes at least a red phase and a green phase, said method comprising: 
 obtaining a plurality of images of a vehicle approaching said intersection from said first direction;    analyzing said plurality of images to predict whether said vehicle will violate said red light phase of said first traffic light;    responsive to a determination said vehicle will violate said red light phase of said first traffic light generating a delay signal indicative of said predicted violation.    
     
     
         38 . The method of  claim 37  further including delaying a change of said second traffic signal from said red light phase to said green light phase responsive to said delay signal.  
     
     
         39 . The method of  claim 37 , wherein said obtaining said plurality of images is performed by an image capturing device comprising at least one video camera.  
     
     
         40 . The method of  claim 37 , wherein analyzing said plurality of images is performed by a collision avoidance unit comprising software executing on a processor.  
     
     
         41 . The method of  claim 37 , further comprising: 
 determining at least one vehicle location associated with said at least one vehicle; and    wherein said determining whether said at least one vehicle will violate said red light phase of said first traffic signal is responsive to said at least one vehicle location.    
     
     
         42 . The method of  claim 37 , further comprising: 
 determining a time remaining in a current yellow light phase; and    wherein said determining whether said at least one vehicle will violate said red light phase of said first traffic signal is responsive to said time remaining in said current yellow light phase.    
     
     
         43 . The method of  claim 37 , further comprising: 
 determining a current speed for said at least one vehicle; and    wherein said determining whether said at least one vehicle will violate said red light phase of said first traffic signal is responsive to said current speed of said at least one vehicle.    
     
     
         44 . The method of  claim 37 , wherein said determining whether said at least one vehicle will violate said red light phase of said first traffic signal further comprises determining a current acceleration for said at least one vehicle.  
     
     
         45 . The method of  claim 37 , wherein said determining whether said at least one vehicle will violate said red light phase of said first traffic signal further comprises computing a time remaining before said at least one vehicle enters said traffic intersection.  
     
     
         46 . The method of  claim 45 , wherein said determining whether said at least one vehicle will violate said red light phase of said first traffic signal further comprises calculating a rate of deceleration required for said at least one vehicle to stop within said time remaining before said vehicle enters said traffic intersection.  
     
     
         47 . The method of  claim 46 , wherein said determining whether said at least one vehicle will violate said red light phase of said first traffic signal further comprises determining whether said required deceleration is larger than a specified deceleration limit value.  
     
     
         48 . An accident avoidance system for an intersection having a traffic signal having a current light phase equal to one of a red light phase and a green light phase, and a pedestrian crosswalk passing through a path of traffic controlled by said first traffic signal, comprising: 
 at least one image capturing device, for capturing a plurality of images of said pedestrian crosswalk, said plurality of images showing at least one pedestrian within said pedestrian crosswalk; and    a computation unit, responsive to said plurality of images and an indication of said current traffic signal light phase, for determining whether said at least one pedestrian in said crosswalk will exit said crosswalk prior to said current traffic signal light phase transitioning from red to green, and for delaying an upcoming green traffic light phase of said traffic signal responsive to a determination that said at least one pedestrian will not exit said crosswalk prior to said current traffic signal light phase transitioning from red to green.    
     
     
         49 . The system of  claim 48 , wherein said image capturing device comprises at least one video camera.  
     
     
         50 . The system of  claim 48 , wherein said computation unit is further responsive to a current speed of said at least one pedestrian within said pedestrian crosswalk.  
     
     
         51 . The system of  claim 48 , wherein said computation unit is further responsive to a current acceleration of said at least one pedestrian within said pedestrian crosswalk.  
     
     
         52 . The system of  claim 48 , wherein said computation unit is further responsive to a current position of said at least one pedestrian within said pedestrian crosswalk.  
     
     
         53 . The system of  claim 48 , wherein said computation unit is further operable to compute a time remaining before said current traffic signal light phase transitions from red to green.