Patent Document

BACKGROUND OF INVENTION 
   The present invention relates generally to collision warning systems, and more particularly to a method and apparatus for warning a vehicle operator of another vehicle within a blind spot of the vehicle. 
   Collision warning systems are becoming more widely used. Collision warning systems provide a vehicle operator knowledge and awareness of objects or vehicles within a close proximity so as to prevent colliding with those objects. Current collision warning systems are unitary in nature in that they only warn the operator of the vehicle containing the collision warning system of a potential collision. A sensor located on a vehicle, upon sensing an object generates an object detection signal, which is communicated to the operator of that vehicle. 
   Warning systems for vehicles that are directed to the rear of the vehicle are known. However, such systems typically are not image-based and thus are subject to false sensing. Other rear-sensing systems monitor the rear of the vehicle without monitoring the transition of a vehicle from the rear of the vehicle to the blind spot. 
   Therefore, it would be desirable to provide an improved blind spot warning system. The improved system may increase reaction time and decrease the probability of a collision occurring. 
   SUMMARY OF INVENTION 
   Accordingly, an advantage of the present invention is to provide an improved blind spot warning system for use in an automotive vehicle. 
   In one aspect of the invention, a warning system for a source vehicle is illustrated. A camera generates a plurality of images. A controller is coupled to an indicator. The controller generates a size signal and position signal for a rear-approaching vehicle. The controller activates an indicator when a rear-approaching vehicle enters a blind spot in response to the size signal and position signal. 
   In a further aspect of the invention, a method of warning of a vehicle within a blind spot comprises: generating a plurality of images of an object; determining a size and a position of the object from the images; determining a transition of the object into the blind spot; and generating a warning when the object enters the blind spot. 
   Another advantage of the present invention is that it increases the reaction time for both operators of the target vehicle and the approaching vehicle. Thereby, decreasing the probability of a collision between the two vehicles. 
   Other advantages and features of the present invention will become apparent when viewed in light of the detailed description of the preferred embodiment when taken in conjunction with the attached drawings and appended claims. 

   
     BRIEF DESCRIPTION OF DRAWINGS 
       FIG. 1  is a top diagrammatic view of a source vehicle relative to four positions of a target vehicle. 
       FIGS. 2A ,  2 B,  2 C, and  2 D are images from the camera of the source vehicle for the four positions of the target vehicle of FIG.  1 . 
       FIG. 3  is a schematic view of a blind spot warning system according to the present invention. 
       FIG. 4  is a flow chart of the operation of the blind spot warning system. 
   

   DETAILED DESCRIPTION 
   In the following figures the same reference numerals will be used to illustrate the same components. While the present invention is described with respect to a particular method and apparatus for blind spot warning, various adaptations may be evident to those skilled in the art. 
   Referring now to  FIG. 1 , a source vehicle  10  having a blind spot warning system  12  is illustrated. A representation of a blind spot  14  is illustrated. The blind spot  14  is the area beyond which the external driver side rear-view mirror  16  cannot see without glancing back. The blind spot  14  may be of many shapes and sizes depending on various factors such as mirror size and vehicle configuration. The blind spot warning system  12  provides an indication to the source vehicle operator as to the entering of a target vehicle  18  within blind spot  14 . 
   Source vehicle  10  has a rear-facing camera  20  having a field of view  22 . The field of view may not overlap or slightly overlap blind spot  14 . Therefore, the present invention monitors the transition from the camera field of view to the blind spot  14 . Camera  20  is preferably a low light camera. Today&#39;s technology allows a small camera to be placed inconspicuously on a rear panel  23  of the vehicle so as not to become aesthetically displeasing. Various locations on the rear of the vehicle including a trunk lid, a tailgate, the bumper, or the rear portion of the roof may all be desirable locations. 
   Target vehicle  18  is show in four locations proceeding from directly behind source vehicle  10  to approaching the source vehicle  10  on the passenger side and eventually entering into blind spot  14 . 
   Referring now to  FIGS. 2A ,  2 B,  2 C, and  2 D, the four positions of target vehicle of  FIG. 1  are shown in perspective view progressing through a trajectory. An image box  24  is used to track target vehicle  18 . 
   Referring now to  FIG. 3 , blind spot warning system  12  is illustrated in further detail. Blind spot warning system  12  includes a controller  30  that is coupled to the rear-facing camera  20  described above. Controller  30  is preferably a microprocessor-based controller having a central processing unit, internal memory such as RAM or ROM, and associated inputs and outputs communicating across a bus. Controller  30  may be a portion of a central vehicle main control unit or stand-alone unit. 
   Controller  30  is coupled to a memory  32  and a timer  34 . Although memory  32  and timer  34  are illustrated as separate components in that of controller  30 , both of these components may be incorporated into controller  30 . 
   Memory  32  may comprise various types of memory Including read only memory (ROM), random access memory (RAM), electrically erasable programmable read only memory, and keep alive memory. Memory  32  is used to store various thresholds and parameters as will be further described below. 
   Timer  34  is a timer such as a clock timer of a central processing unit within controller  30 . Timer  34  is capable of timing the duration of various events as well as counting up or counting down. For example, timer  34  may be used to time the progression of the trajectory of the target vehicle  18 . 
   Controller  30  is coupled to an indicator  36 . Indicator  36  may be one of a variety of types of indicators that may include an audible indicator or a visual indicator or a combination of both. Indicator  36  may include a speaker  38  to generate audible indications, a light bulb or LED  40  to provide visual indications, or a computer screen  42  such as that provided in navigation systems to generate various types of warnings. Indicator  36  may vary in intensity, amplitude, size, or in any way so as to communicate to the operator of source vehicle  10  the potential for colliding with target vehicle  18 . 
   Controller  30  may include various processing which may be incorporated as separate devices or as an integral part of the controller. Controller  30  may, for example, include a video capture system  50 , an image processing system  52 , a neural net processor  54 , and an object tracking system  56 . Each of the systems  50 - 56  may be coupled together. 
   Video capture system  50  receives the information from camera  20  and forms a digital image thereof. Although the video capture system  50  is illustrated within controller  30 , rear-facing camera  20  may also provide such information. 
   Image processing system  52  may be used to process the digital image. Various types of processing include the formation of an image box  24  illustrated in  FIGS. 2A-2D . By monitoring the critical pixels in the image, other information such as the image size and trajectory may be determined. The image box  24  corresponds to the vehicle size. 
   Neural net processor  54  may be implemented in a single chip within controller  34 . Neural net processor  54  receives the information from image processing system  52  and determines the presence of a vehicle within the blind spot or entering the blind spot. Based on the trajectory information, the track of the object, the increasing size of the object, the neural net processor  54  may be trained to recognize the potential for collision with a vehicle in the blind spot. Various types of systems are possible with various levels of neural net processors  54 . At a minimum, the size and position of the target vehicle must be known. 
   Object tracking system  56  creates a temporal history of the object within the field of view in the memory. By knowing the temporal history the neural net processor  54  causes controller  30  to initiate an indication as to the presence of a vehicle within the blind spot as the target vehicle transitions into the blind spot. 
   Referring now to  FIG. 4 , a method for operating the blind spot warning system  12  is described. In step  60 , an image is received from the camera  20 . In step  62  the image is captured, preferably for each frame. In step  64  the image is processed based on the position of the pixels therein. The system recognizes the position of the pixels and an object therein and determines various characteristics of the object such as the size of the object, the position of the object, and the track of the object (using the temporal history). Based upon the various types of characteristic information from the images, step  66  classifies the object based on the object information. By tracking the time and the change in size of the object, it is apparent that a vehicle approaching the rear of the vehicle will have an increasingly larger size and ultimately the track will track toward the blind spot. Based on the classification, a threat or potential threat is determined in step  68 . If no threat is apparent such as the vehicle is not within the blind spot, step  60  is repeated. In step  68 , if a threat is determined by the neural net processor  54 , the indicator is activated in step  70 . The indicator may include one or several of the different indicators described above. 
   Thus, by tracking the size and position the trajectory of the object such as a rear-approaching vehicle may easily be determined. 
   While particular embodiments of the invention have been shown and described, numerous variations and alternate embodiments will occur to those skilled in the art. Accordingly, it is intended that the invention be limited only in terms of the appended claims.

Technology Category: 7