sensor.reset()
sensor.set_pixformat(sensor.RGB565) # 灰度更快(160x120 max on OpenMV-M7)
sensor.set_framesize(sensor.QQVGA)
sensor.skip_frames(time = 2000)
sensor.set_auto_whitebal(False)
clock = time.clock()
class Rec(object):
    flag = 0
    x = 0
    y = 0

def Find_Max(rects):
    max_size=1
    if rects:
        max_rect = 0
        for rect in rects:
          rect_size =rect.w()*rect.h()
          if ((rect_size > max_size) & (rect_size > 100)) :#& (blob.density()<1.2*math.pi/4) & (blob.density()>0.8*math.pi/4)
            if ( math.fabs( rect.w() / rect.h() - 1 ) < 2.0 ) :
                 max_rect=rect
                 max_size = rect.w()*rect.h()
        return max_rect


while(True):
    clock.tick()
    img = sensor.snapshot()
    for r in img.find_rects(threshold = 12000):
      img.draw_rectangle(r.rect(),color = (255, 0, 0))
      for p in r.corners(): img.draw_circle(p[0], p[1], 5, color = (0, 255, 0))
      max_rect = Find_Max(p)
      img.draw_cross(max_rect.x() + max_rect.w()//2, max_rect.y() + max_rect.h()//2)
      x1 = max_rect.x() + max_rect.w()//2
      y1 = max_rect.y() + max_rect.h()//2
      fps=int(clock.fps())
      Message.Ctr.T_ms = (int)(1000/fps)
      img.draw_cross(x1, y1)
      Rec.flag = 1
      Rec.x = x1-80
      Rec.y = y1-60
         #print(r)
      print(' x= ',Rec.x,'y= ',Rec.y,'fps',fps,'T_ms',Message.Ctr.T_ms)
      LED(3).toggle()
      print("flag= ",Rec.flag)
      Message.UartSendData(Message.DotDataPack(1,Rec.flag,Rec.x,Rec.y,Message.Ctr.T_ms))