void startline(uchar hang_begin,uchar hang_end) 
{ 
 int i,j,point_field=0,count,cycle=0,sum; 
 for(i=rows-1;i>=1;i--) 
 { 
 point_field+=path_mid-path_mid[i-1]; 
 } 
 point_field/=rows; 
 if(point_field>-10&&point_field<10) 
 { 
 for(i=hang_begin;i>=hang_end;i--) 
 { 
 count=sum=0; 
 for(j=0;j<cols-3;j++) 
 { 
 if(image[j]<threshold&&image[j+1]<threshold&&image[j+2]>=threshold&&image[j+3]>=threshold) 
 { 
 if(j-sum>5) 
 { 
 sum=j; 
 count++; 
 } 
 } 
 if(image[j]>=threshold&&image[j+1]>=threshold&&image[j+2]<threshold&&image[j+3]<threshold) 
 { 
 if(j-sum>5) 
 { 
 sum=j; 
 count++; 
 } 
 } 
 } 
 if(count>=5) 
 cycle++; 
 } 
 if(cycle>3) 
 motor_braking(); 
 } 
}