使用OpenCV-Python外接摄像头打不开问题
使用OpenCV-Python外接摄像头打不开
情况描述
使用OpenCV-Python打开摄像头常用的代码是这样的：
import cv2 as cv
cap = cv.VideoCapture(0)
flag = cap.isOpened()
while (flag):
ret, frame = cap.read()
笔者采用这种方法来打开电脑自带的摄像头是没有问题的，但是近期购入的一个新的摄像头，发现采用这种方式打开会提示：
WARN:0] global C:\projects\opencv-python\opencv\modules\videoio\src\cap_msmf.cpp (1113) SourceReaderCB::OnReadSample videoio(MSMF): OnReadSample() is called with error status: -1072875772
[ WARN:0] global C:\projects\opencv-python\opencv\modules\videoio\src\cap_msmf.cpp (1125) SourceReaderCB::OnReadSample videoio(MSMF): async ReadSample() call is failed with error status: -1072875772
[ WARN:1] global C:\projects\opencv-python\opencv\modules\videoio\src\cap_msmf.cpp (1159) CvCapture_MSMF::grabFrame videoio(MSMF): can't grab frame. Error: -1072875772
[ WARN:1] global C:\projects\opencv-python\opencv\modules\videoio\src\cap_msmf.cpp (674) SourceReaderCB::~SourceReaderCB terminating async callback
经查阅资料
找到了问题所在，采用默认的API控制出错。
解决方法
在VideoCapture后加上cv.CAP_DSHOW
修正后代码如下：
import cv2 as cv
cap = cv.VideoCapture(1,cv.CAP_DSHOW) #更改API设置
flag = cap.isOpened()
index = 1
while (flag):
ret, frame = cap.read()
frame = cv.flip(frame, 1) # 水平翻转
cv.imshow("Capture_Paizhao", frame)
k = cv.waitKey(1) & 0xFF
if k == ord('s'): # 按下s键，进入下面的保存图片操作
cv.imwrite(r"F:\PyCharm\Camera calibration\Aruco_Identify\0" + str(index) + ".jpg", frame)
print(cap.get(3))
print(cap.get(4))
print("save" + str(index) + ".jpg successfuly!")
print("-------------------------")
index += 1
elif k == ord('q'): # 按下q键，程序退出
break
cap.release()
cv.destroyAllWindows()