python - TypeError:来自Jetson Nano上的Raspberry Pi Camera的cv2.imread()的错误参数类型

Question

我正在使用Python 3.6.9，OpenCV版本4.1.0和最新版本的Ubuntu在Jetson Nano上运行树莓派相机。我正在运行代码:

import cv2
print(cv2.__version__)
dispW=320
dispH=240
flip=2
cam_set='nvarguscamerasrc !  video/x-raw(memory:NVMM), width=3264, height=2464, format=NV12, framerate=21/1 ! nvvidconv flip-method='+str(flip)+' ! video/x-raw, width='+str(dispW)+', height='+str(dispH)+', format=BGRx ! videoconvert ! video/x-raw, format=BGR ! appsink'
cam = cv2.VideoCapture(cam_set)
while True:
    ret, frame = cv2.imread(cam)
    cv2.imshow('Camera',frame)
    if cv2.waitKey(1)==ord('q'):
        break
cam.release()
cv2.destroyAllWindows()

当我运行它时，它将引发一个错误，并追溯到第11行，并说“ret，frame = cv2.imread(cam)”具有TypeError:内置操作的错误参数类型。我可以使用opencv加载图像，但是运行视频似乎总是会引发此错误。命令行中的“ls -l / dev / video0”工作正常，因此我知道我已连接到摄像机。谢谢!

Answer 1

根据文档:Python: cv2.imread(filename[, flags]) → retvalimread在需要此代码段时会期望有一条路径:

import numpy as np
import cv2

cap = cv2.VideoCapture(0)

while(True):
    # Capture frame-by-frame
    ret, frame = cap.read()

    # Our operations on the frame come here
    gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)

    # Display the resulting frame
    cv2.imshow('frame',gray)
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break

# When everything done, release the capture
cap.release()
cv2.destroyAllWindows()