opencv - 如何从 Jetson TX1 嵌入式摄像头接收图像？

Question

我用最新的 Jetpack (Linux For Tegra R23.2) 刷新了我的 Jetson TX1，并且以下命令完美运行:

gst-launch-1.0 nvcamerasrc fpsRange="30.0 30.0" ! 'video/x-raw(memory:NVMM), width=(int)1920, height=(int)1080, format=(string)I420, framerate=(fraction)30/1' ! nvtee ! nvvidconv flip-method=2 ! 'video/x-raw(memory:NVMM), format=(string)I420' ! nvoverlaysink -e

我尝试使用以下 python 程序从网络摄像头接收图像:

来源:http://opencv-python-tutroals.readthedocs.org/en/latest/py_tutorials/py_gui/py_video_display/py_video_display.html

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()

我收到以下错误:

OpenCV Error: Assertion failed (scn == 3 || scn == 4) in cvtColor, file /hdd/buildbot/slave_jetson_tx_2/35-O4T-L4T-Jetson-L/opencv/modules/imgproc/src/color.cpp, line 3739
Traceback (most recent call last):
  File "webcam.py", line 11, in <module>
    gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
cv2.error: /hdd/buildbot/slave_jetson_tx_2/35-O4T-L4T-Jetson-L/opencv/modules/imgproc/src/color.cpp:3739: error: (-215) scn == 3 || scn == 4 in function cvtColor

我知道问题是它无法从网络摄像头接收图像。我还更改了代码以仅显示从网络摄像头接收到的图像，但它给了我错误，这意味着它没有从摄像头获取图像。

我还尝试通过以下代码使用 C++:

#include "opencv2/opencv.hpp"
using namespace cv;
int main(int argc, char** argv)
{
    VideoCapture cap;
    // open the default camera, use something different from 0 otherwise;
    // Check VideoCapture documentation.
    if(!cap.open(0))
        return 0;
    for(;;)
    {
          Mat frame;
          cap >> frame;
          if( frame.empty() ) break; // end of video stream
          imshow("this is you, smile! :)", frame);
          if( waitKey(1) == 27 ) break; // stop capturing by pressing ESC 
    }
    // the camera will be closed automatically upon exit
    // cap.close();
    return 0;
}

使用

编译没有任何错误

g++ webcam.cpp -o webcam `pkg-config --cflags --libs opencv` 

但同样，当我运行程序时，我收到此错误:

$ ./webcam
Unable to stop the stream.: Device or resource busy
Unable to stop the stream.: Bad file descriptor
VIDIOC_STREAMON: Bad file descriptor
Unable to stop the stream.: Bad file descriptor

我错过了什么？在运行此程序之前，我应该运行任何命令来激活网络摄像头吗？

Answer 1

根据 nvidia 论坛，您需要正确设置 gstreamer 管道。目前 opencv 无法自动检测 nvcamera 的流。

我让它工作的唯一方法是使用 Opencv3 和这行代码来获取视频:

cap = cv2.VideoCapture("nvcamerasrc !video/x-raw(memory:NVMM), width=(int)640, height=(int)480, format=(string)I420, framerate=( fraction)30/1 !nvvidconv flip-method=2 !video/x-raw, format=(string)I420 !videoconvert !video/x-raw, format=(string)BGR !appsink")/p>