python opencv

opencv

今天使用opencv画bounding box

python下使用opencv修改图片：

import cv2

 

opencv2.4.13显示图片，等待按键输入

cv2.imshow("iamge",frame)
cv2.waitKey(0)

 

 

 opencv2.4.13添加文字cv2.putText，存在不支持\n换行的问题，如果要输出换行，按如下所示：

https://blog.csdn.net/lanchunhui/article/details/71229235

putText(图片名，文字，文字位置，字体，大小，颜色，粗细）

　　　　　str_to_write="line1\nline2\nline3\nline4"
        y0, dy = 50, 25
        for i, txt in enumerate(str_to_write.split('\n')):
            y = y0+i*dy
            cv2.putText(frame,txt,(50,y),cv2.FONT_HERSHEY_COMPLEX,0.4,(0,0,255),1)

 

添加文字：cv2.putText()，参考http://blog.csdn.net/gan_player/article/details/78155283?utm_source=debugrun&utm_medium=referral

获取图片宽/高：参考http://blog.csdn.net/jacke121/article/details/76152242

 

opencv3从视频中获取单帧图像

import cv2 

videoCapture = cv2.VideoCapture()
videoCapture.open('E:/video/1-1.avi')

fps = videoCapture.get(cv2.CAP_PROP_FPS)
frames = videoCapture.get(cv2.CAP_PROP_FRAME_COUNT)
#fps是帧率，意思是每一秒刷新图片的数量，frames是一整段视频中总的图片数量。
print("fps=",fps,"frames=",frames)

for i in range(int(frames)):
    ret,frame = videoCapture.read()
    cv2.imwrite("E:/video/pictures/1-1.avi(%d).jpg"%i,frame)

opencv2.4.13从视频中获取单帧图像

def drawpoint(filename):
    cap=cv2.VideoCapture()
    cap.open(filename)
    frames=cap.get(cv2.cv.CV_CAP_PROP_FRAME_COUNT)#opencv2 获取总帧数
for i in range(int(frames)):
        ret,frame=cap.read()
　　　　　#do sth to frame...
return