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我试图从OpenCV的网站上运行Python的例子:OpenCV的例子错误 - 类型错误: 'NoneType' 对象未标化的
http://docs.opencv.org/trunk/d7/d8b/tutorial_py_lucas_kanade.html
import numpy as np
import cv2
cap = cv2.VideoCapture('slow.flv')
# params for ShiTomasi corner detection
feature_params = dict(maxCorners = 100,
qualityLevel = 0.3,
minDistance = 7,
blockSize = 7)
# Parameters for lucas kanade optical flow
lk_params = dict(winSize = (15,15),
maxLevel = 2,
criteria = (cv2.TERM_CRITERIA_EPS | cv2.TERM_CRITERIA_COUNT, 10, 0.03))
# Create some random colors
color = np.random.randint(0,255,(100,3))
# Take first frame and find corners in it
ret, old_frame = cap.read()
old_gray = cv2.cvtColor(old_frame, cv2.COLOR_BGR2GRAY)
p0 = cv2.goodFeaturesToTrack(old_gray, mask = None, **feature_params)
# Create a mask image for drawing purposes
mask = np.zeros_like(old_frame)
while(1):
ret,frame = cap.read()
frame_gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
# calculate optical flow
p1, st, err = cv2.calcOpticalFlowPyrLK(old_gray, frame_gray, p0, None, **lk_params)
# Select good points
good_new = p1[st==1]
good_old = p0[st==1]
# draw the tracks
for i,(new,old) in enumerate(zip(good_new,good_old)):
a,b = new.ravel()
c,d = old.ravel()
mask = cv2.line(mask, (a,b),(c,d), color[i].tolist(), 2)
frame = cv2.circle(frame,(a,b),5,color[i].tolist(),-1)
img = cv2.add(frame,mask)
cv2.imshow('frame',img)
k = cv2.waitKey(30) & 0xff
if k == 27:
break
# Now update the previous frame and previous points
old_gray = frame_gray.copy()
p0 = good_new.reshape(-1,1,2)
cv2.destroyAllWindows()
cap.release()
我使用Python 3运行这个例子
它的工作原理,但只有5-15秒,我的视频,然后停止与下一个错误:
Traceback (most recent call last): File "o.py", line 28, in good_new = p1[st==1] TypeError: 'NoneType' object is not subscriptable
这个例子有什么问题?
['calcOpticalFlowPyrLK'](http://docs.opencv.org/3.0-beta/ modules/video/doc/motion_analysis_and_object_tracking.html)可能还没有找到任何_nextPts_,因此'p1'是空的。为什么不在选择优秀点之前先检查空虚?加'if p1 not None:......'我还建议打印出它的价值,看看是否属实。让我知道它是否工作;) – eshirima
是的,我做到了这一点,并在打印空阵列 - [],我试过'尝试抓住'和'继续'当这种情况发生,但随后视频变得只是暂停 – user924
你也可以只封装你的代码在if语句里面,因为如果'good_new'是空的,它就没有意义了 – eshirima