Abstract:
When a temperature T detected by a thermistor built inside a camera unit exceeds a preset temperature T 1 , at least a process, among processes executed by a CPU built inside the camera unit, that relates only to LKA or AHB (such as a white line recognizing process) is stopped. Then, the amount of heat generated by the CPU decreases, whereby the temperature inside the housing also decreases. In this way, even when the PCS control is continuously performed by continuing electric power supply to an imaging element in the camera unit, performance of the imaging element can be maintained in some cases, thus allowing the electric power supply to the imaging element to continue in a satisfactory manner for a long period.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based on and claims the benefit of priority from earlier Japanese Patent Application No. 2013-060200 filed Mar. 22, 2013, the description of which is incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Technical Field 
     This invention relates to a vehicle controller controlling a vehicle by using an image sensor capturing an image of the surrounding of the vehicle. 
     2. Related Art 
     Conventionally, various vehicle controllers have been suggested, the vehicle controllers controlling vehicles by using image sensors capturing images of the surroundings of the vehicles. For example, a device which recognizes lane markers separating traveling lanes on the basis of the image has been suggested. The device applies rotation torque to a steering shaft such as to prevent deviation from the lane. Such a process for recognizing the lane marker is easily affected by thermal noise. Accordingly, if the temperature of the image sensor exceeds a threshold, it is suggested the electric power supply to the image sensor is stopped (for example, see PTL 1). 
     CITATION LIST 
     Patent Literature 
     [PTL 1] JP-A-2010-64513 
     SUMMARY 
     Technical Problem 
     The temperature increase of the image sensor is affected also by heat from a controller portion and the like disposed with the image sensor in a common casing. However, in the PTL 1, suppressing heat from the controller portion and continuing the electric power supply to the image sensor is not considered at all. Accordingly, the present disclosure has an object to provide a vehicle controller which can continue electric power supply to an image sensor for a long time by reducing heat from a controller portion disposed with the image sensor in a common casing. 
     Solution to Problem 
     In a vehicle controller of this disclosure made for solving the above-described object, an image sensor and a controller portion are disposed in the same casing. The image sensor captures an image of surroundings of a vehicle. The controller portion performs a plurality of types of processes for processing the image captured from the image sensor. A temperature detector portion detects a temperature of the inside of the casing or a temperature of the image sensor, and stopping means stops a part of the processes executed by the controller portion, if the temperature detected by the temperature detector portion exceeds a predetermined threshold. This reduces the heat from the controller portion, which causes the temperature of the casing and the temperature of the image sensor to lower. As a result, even if electric power supply to the image sensor is continued, performance of the image sensor can sometimes be maintained, and accordingly the electric power supply to the image sensor can be maintained well for a long time. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the accompanying drawings: 
       In the accompanying drawings: 
         FIG. 1  is a schematic perspective view showing a placement of an camera unit according to an embodiment; 
         FIG. 2  is a block diagram showing a configuration of a vehicle controller using the camera unit; and 
         FIG. 3  is a flow chart showing processes executed in the vehicle controller. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Configuration of Embodiment 
     Hereinafter is described an embodiment with the drawings. As shown in  FIG. 1 , a camera unit  10  configures a part of a vehicle controller of this embodiment. The camera unit  10  is attached to a top center of a windshield  3  of a vehicle  1  near a base of a rear-view mirror  5  behind the rear-view mirror. 
     As shown in  FIG. 2 , in addition to an image sensor  11  such as a CCD, a CPU  12  and a thermistor  13  are provided inside a casing  10 A of the camera unit  10 . The CPU  12  executes processes for controlling the image sensor  11 . In this embodiment, the CPU  12  performs a plurality of types of image processing on the basis of image signals inputted from the image sensor  11 , and obtains information on peripheral objects of the vehicle and status information of the own vehicle. Further, the CPU  12  executes a stop process described below on the basis of a temperature signal of the inside of the casing  10 A, the temperature signal inputted from the thermistor  13 . The thermistor  13  is provided at a position where the temperature of the inside of the casing  10 A, preferably the temperature of the image sensor  11  is detectable. 
     The vehicle controller of this embodiment has a DSS ECU (driver support system electronic control unit: referred to as simply DSS, below). The DSS  20  is connected through a local CAN  18  to sensors detecting environment surrounding the vehicle, such as a camera unit  10 , a millimeter-wave radar  17  detecting obstacles ahead of the vehicle  1 , and the like. The DSS  20  is connected to operation devices which the driver operates through their controllers. The DSS  20  controls the operation device depending on the environment surrounding the vehicle, thereby supporting driving operation of the driver. 
     Specifically, the DSS  20  of this embodiment is connected to an ECU  33  controlling a brake  31 , another ECU  43  controlling a steering wheel  41 , another ECU  53  controlling an alarm device  51 , and another ECU  63  controlling a headlight  61  through a global CAN  70 . 
     Control in this Embodiment 
     Thus, the vehicle controller of this embodiment configured as shown in the block diagram of  FIG. 2  executes control, such as PCS (forward crash avoidance), LKA (lane keep assist), and AHB (automatically light High/Low switching). Now is described an overview of each control. 
     PCS: The control is for automatically activating the brake  31  to prevent collision when the vehicle  1  almost collide an obstacle ahead of the vehicle  1 . In the control, the CPU  12  of the camera unit  10  calculates the distance to the obstacle such as a human, a vehicle and the like, the position, and the size of the obstacle. The DSS  20  instructs the ECU  33  on activating timing of the brake  31  or strength of the braking force on the basis of the information from the camera unit  10  and the millimeter wave radar  17 . The ECU  33  sends instructions to actuators for activating the brake  31 . 
     LKA: The control is for giving the steering wheel  41  an opposing force to return the vehicle  1  to the original lane, when the vehicle  1  is about to deviate from the lane (guideway). In the control, the CPU  12  of the camera unit  10  calculates a deviation degree of the own vehicle from the center of the traveling lane, i.e. how much the own vehicle is deviated from the center or whether the own vehicle is deviated from the white line, on the basis of the image captured by the image sensor  11 . In response to the process by the CPU  12 , the DSS  20  provides the instruction for giving the opposing force to the steering wheel  41 , or provides an instruction for issuing an alarm when the vehicle  1  deviates from the lane. In response to the instruction, the ECU  43  sends an instruction to actuators for actuating the steering wheel  41 , and the ECU  53  sends an instruction to the alarm device  51 . 
     AHB: The control is for automatically switching between High beam and Low beam when a leading vehicle or an oncoming appears. In the control, the CPU  12  of the camera unit  10  calculates the distance to and the position of the leading vehicle or oncoming vehicle on the basis of the image captured by the image sensor  11 . In response to the process by the CPU  12 , the DSS  20  determines whether it should set the headlight to High beam or Low beam, and the ECU  63  instructs the headlight  61  to switch between High beam and Low beam. 
     It should be noted that the following Table 1 shows assignments which the controllers (the CPU  12  of the camera unit  10 , the DSS  20  and the ECUs  33  to  63 ) have in each control of the PCS, LKA and AHB. 
     
       
         
               
               
               
               
             
               
               
               
               
             
           
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                   
                   
                 Corresponding 
               
               
                   
                 Camera unit&#39;s 
                 DSS&#39;s 
                 ECU&#39;s 
               
               
                   
                 assignment 
                 assignment 
                 assignment 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 PCS 
                 Calculate the 
                 Provide the 
                 Instruct the 
               
               
                 Forward crash 
                 distance to, the 
                 instruction on 
                 brake 
               
               
                 avoidance 
                 position and 
                 braking timing 
               
               
                 Pre-Crash-Safety 
                 size of obstacles 
                 and braking 
               
               
                   
                 such as a 
                 force 
               
               
                   
                 human, a 
               
               
                   
                 vehicle and the 
               
               
                   
                 like 
               
               
                 LKA 
                 Deviation 
                 Instruction the 
                 Instruct the 
               
               
                 Lane Keep Assist 
                 degree of the 
                 steering wheel 
                 steering wheel 
               
               
                 Lane-Keep-Assist 
                 own vehicle 
                 on the opposing 
                 Instruct alarm 
               
               
                   
                 from the center 
                 force, 
                 device 
               
               
                   
                 of the traveling 
                 Alarm when the 
               
               
                   
                 lane (how much 
                 deviation occurs 
               
               
                   
                 the own vehicle 
               
               
                   
                 is deviated from 
               
               
                   
                 the center or 
               
               
                   
                 whether the 
               
               
                   
                 own vehicle is 
               
               
                   
                 deviated from 
               
               
                   
                 the white line) 
               
               
                 AHB 
                 Distance to and 
                 Determine 
                 Instruct the 
               
               
                 Automatically 
                 position of a 
                 whether the 
                 light 
               
               
                 light High/Low 
                 leading or 
                 light is switched 
               
               
                 switching 
                 oncoming 
                 to High or Low 
               
               
                 Auto-High-Beam 
                 vehicle 
               
               
                   
               
             
          
         
       
     
     Here, if the internal temperature of the casing  10 A detected by the thermistor  13  rises, it becomes difficult to ensure performance of the image sensor  11  because of an effect of thermal noise and the like. Accordingly, when an ignition switch of the vehicle  1  is turned on, the CPU  12  executes the processes shown in  FIG. 3  on the basis of the programs stored on the ROM. 
     As shown in  FIG. 3 , when the flow is initiated, at first, the temperature detected by the thermistor  13  is defined as a temperature T in S 1  (S means a step: the same is applied below). In the next S 2 , it is determined whether the temperature T is higher than a temperature T 1  predetermined as a temperature where all the controls can be performed stably. In a case of T≦T 1  (S 2 :N), the flow proceeds to S 3 . 
     In S 3 , of the processes in the CPU  12 , all the PCS, LKA and AHB processes are permitted. In S 4 , the permitted processes are notified to the DSS  20 , thereafter the flow proceeds to S 1 . As a result, if the temperature T is low enough (S 2 : N), the CPU  12  cooperates with the DSS  20  and the like to execute all the PCS, LKA and AHB controls. 
     On the other hand, if the temperature T is higher than the temperature T 1  (S 2 : Y), the flow proceeds to S 6 , and it is determined whether the temperature T is higher than a temperature T 2  which is predetermined to be higher than the T 1 . In a case of T≦T 2  (S 6 : N), the flow proceeds to S 7 , only the PCS process among the processes by the CPU  12  is permitted, and the flow proceeds to S 4 . That is, stepwise threshold temperatures are set to reduce the load of the CPU  12  in step wise manner. In a case of T&gt;T 2  (S 6 : Y), the flow proceeds to S 9 , all the PCS, LKA and AHB processes are stopped, and the flow proceeds to S 4 . In this embodiment, the temperature T 2  is set on the basis of the operation guarantee temperature of the image sensor  11 . That is, even if the temperature in the CPU 12  is within the operation guarantee temperature of the CPU  12 , when the operation guarantee temperature of the image sensor  11  is lower than that of the CPU  12 , the stopping process is performed. 
     [Advantageous Effects of the Embodiment and Modifications] 
     In this embodiment, if the temperature T detected by the thermistor  13  exceeds the predetermined temperature T 1  (S 2 : Y), of the processes which the CPU  12  executes, at least only the LKA or AHB process (for example, recognition process of white lines) is stopped (S 7 ). This reduces the heat from the CPU  12 , which causes the internal temperature of the casing  10 A and the temperature of the image sensor  11  to lower. As a result, even if electric power supply to the image sensor  11  is kept to continue the control of the PCS, performance of the image sensor  11  can sometimes be maintained, accordingly the electric power supply to the image sensor  11  can be maintained sufficiently for a long time. This can substantially increase the operation guarantee temperature of the camera unit  10  for executing the control of the PCS. 
     Further, in this embodiment, because the process permitted for the CPU 1   2  is notified to the DSS  20  (S 4 ), the DSS  20  can be prevented from mistaking the processes. If the temperature T exceeds the temperature T 2  which is set to be higher than the temperature T 1  (S 6 : Y), all processes in the CPU  12  are stopped. This can reduce the internal temperature T of the casing  10 A and the temperature of the image sensor  11  further quickly. 
     In this embodiment, the CPU  12  corresponds to the first controller portion, stopping means and notifying means. Thermistor  13  corresponds to the temperature detector portion, the DSS  20  corresponds to second controller portion, respectively. Of the processes by the CPU  12 , S 7  and S 9  correspond to the stopping means, and S 4  corresponds to notifying means, respectively. The present invention is not limited to the above-described embodiment, and modifications can be made without departing from the scope of the present invention. For example, the CPU  12  may execute control processes other than the PCS, LKA and AHB, and an order of the processes to be stopped may be changed. However, in the above-described embodiment, since, of the three PCS, LKA and AHB controls, the PCS control is performed to the last, safety of the vehicle  1  can be better ensured. 
     REFERENCE SIGNS LIST 
     
         
           1  . . . Vehicle 
           10  . . . Camera unit 
           10 A . . . Casing 
           11  . . . Image sensor 
           12  . . . CPU 
           13  . . . Thermistor 
           20  . . . DSS 
           31  . . . Brake 
           33 ,  43 ,  53 ,  63  . . . ECU 
           41  . . . Steering wheel 
           51  . . . Alarm device 
           61  . . . Headlight