Tracking tagging system (Python + opencv)

Using Python + opencv to write a simple tagging system
Mark the target with the mouse to record the upper left corner and lower right corner of the target
Then there is a direction key to jump to the next frame.
It can be used for simple tagging.
The Code is as follows:

'''Created on May 31, 2013@author: Yang'''# car.pyimport cvimport timeimport threadimport pythoncomimport pyHookimport osimport sysdef timer(no, interval):#     global x,y#     global move_x,move_y    pythoncom.PumpMessages()    def onKeyboardEvent(event):        global lins    key = event.Key    if key=='Up':        lins = 1    if key=='Down':        lins = 2    if key=='Left':        lins = 3    if key=='Right':        lins = 4    #print "Key:", event.Key#im=cv.CreateImage((400,400),cv.CV_8UC3,1)#    this is the method to define a mouse callback function. Several events are given in OpenCV documentationdef my_mouse_callback(event,x,y,flags,image):    global x1,y2,x2,y1    global flag    global box    global temp        try:        cv.Copy(image, temp)        #print type(box)        for j in xrange(len(box)):            xx1 = box[j][0]            yy1 = box[j][1]            xx2 = box[j][2]            yy2 = box[j][3]            cv.Rectangle(temp,(xx1,yy1),(xx2,yy2),(255,0,0),2,8)    except:        pass            if event==cv.CV_EVENT_LBUTTONDOWN:        # here event is left mouse button double-clicked        x1 = x        y1 = y        #print x,y        flag = 1        #cv.Rectangle(im,(x1,y1),(x,y),(255,0,0),2,8)    if event==cv.CV_EVENT_LBUTTONUP:        x2 = x        y2 = y        #print x1,y1,x2,y2        cv.Rectangle(temp,(x1,y1),(x2,y2),(255,0,0),2,8)        t = [x1,y1,x2,y2]        box.append(t)        flag = 0    #if event==cv.CV_EVENT_MOUSEMOVE:    if flag==1:        cv.Rectangle(temp,(x1,y1),(x,y),(255,0,0),2,8)def writebox(ff, box):    try:        for item in box:            t1 = item[0]            t2 = item[1]            t3 = item[2]            t4 = item[3]            ff.write(str(t1)+' '+str(t2)+' '+str(t3)+' '+str(t4)+' ')        ff.write('\n')    except:        pass    im = cv.LoadImage("frame_0000.jpg")cv.NamedWindow("Display",cv.CV_WINDOW_AUTOSIZE)x1 = 0y2 = 0x2 = 0y1 = 0flag = 0lins = 0box = []temp = cv.CreateImage(cv.GetSize(im), 8, 3)hm = pyHook.HookManager()hm.KeyDown = onKeyboardEventhm.HookKeyboard()#cv.SetMouseCallback("Display",my_mouse_callback,im)  thread.start_new_thread(timer,(1,1))  #binds the screen,function and image  path = 'F:/PETS2012/pets-new/S2_L1/Crowd_PETS09/S2/L1/Time_12-34/View_007'f = os.listdir(path)labout = open('view007.txt','w')count = 0for imagename in f:    imagepath = path+'/'+imagename     image = cv.LoadImage(imagepath)        cv.Copy(image,temp)    cv.SetMouseCallback("Display",my_mouse_callback,image)        while(1):        #cv.ShowImage("Display",im)        #cv.Rectangle(im,(80,88),(80+212,88+225),(0,0,0),-1)        #cv.ShowImage("Display",im)        #cv.ShowImage("Display",im)        cv.ShowImage("Display", temp)        k = cv.WaitKey(40)        if k=='f':            break        if lins==3:            lins=0            #temp = cv.CreateImage(cv.GetSize(im), 8, 3)            writebox(labout, box)            box=[]            break            print lins        if lins==4:            lins=0            #temp = cv.CreateImage(cv.GetSize(im), 8, 3)            labout.write(str(count)+' ')            writebox(labout, box)            labout.write('\n')            box=[]            break            print lins            count += 1    #if cv.WaitKey(15)%0x100==27:break        # waiting for clicking escape keycv.DestroyWindow("Display")labout.close()