Python cv2.line和cv2.circle返回无
我试图使用cv2.calcOpticalFlowPyrLK在Python上实现光流的Lucas Kanade算法。但是,当我试图画一条线来连接当前点和以前的点以及点本身时,函数将不返回任何值 这是密码Python cv2.line和cv2.circle返回无,python,opencv,python-2.7,numpy,Python,Opencv,Python 2.7,Numpy,我试图使用cv2.calcOpticalFlowPyrLK在Python上实现光流的Lucas Kanade算法。但是,当我试图画一条线来连接当前点和以前的点以及点本身时,函数将不返回任何值 这是密码 #draw the overlaying tracking img for i,(new,old) in enumerate(zip(good_new,good_old)): a,b = new.ravel() #tmp new value c,d = old.ravel() #t
#draw the overlaying tracking img
for i,(new,old) in enumerate(zip(good_new,good_old)):
a,b = new.ravel() #tmp new value
c,d = old.ravel() #tmp old value
#draws a line connecting the old point with the new point
mask = cv2.line(mask,(a,b),(c,d),color[i].tolist(),2) #returns None... why??
#draws the new point
frame = cv2.circle(frame,(a,b),5,color[i].tolist(),-1) #returns None... why??
img = cv2.add(frame,mask)
#show on window
cv2.imshow("frame",img)
a、 b、c、d是numpy
frame是从网络摄像头读取的我的值
掩码初始化为一个零数组
颜色是一个随机数组
这是我在尝试imshow时收到的错误消息
error: /Users/vagrant/pisi-64bit/tmp/opencv-2.4.5-2/work/opencv-2.4.5/modules/core/src/array.cpp:2482: error: (-206) Unrecognized or unsupported array type in function cvGetMat
我真的很感谢你的帮助 根据OpenCV文档,cv2.line()和cv2.circle()始终不返回任何值 这些方法是就地方法,因此它们会更改您传递给它们的第一个参数。请参阅描述以下类型函数的堆栈溢出问题: 您的固定代码应该如下所示:
#draw the overlaying tracking img
for i,(new,old) in enumerate(zip(good_new,good_old)):
a,b = new.ravel() #tmp new value
c,d = old.ravel() #tmp old value
#draws a line connecting the old point with the new point
cv2.line(mask,(a,b),(c,d),color[i].tolist(),2) #returns None... why??
#draws the new point
cv2.circle(frame,(a,b),5,color[i].tolist(),-1) #returns None... why??
img = cv2.add(frame,mask)
我花了很长时间才弄明白这个bug,因为它完全是从opencv教程复制的。他们真的应该编辑它