OpenCV java无法打开网络摄像头

Question

我正在学习 OpenCV。我正在使用 OpenCV 3.2.0 jar。我正在尝试用它打开我的网络摄像头，但出现错误。这是我的代码

Java：

import org.opencv.core.Core;
import org.opencv.core.Mat;
import org.opencv.videoio.VideoCapture;


public class WebCam {
    public static void main(String[] args) {
    System.loadLibrary(Core.NATIVE_LIBRARY_NAME);

    VideoCapture videoCapture = new VideoCapture(0);
    videoCapture.open("the video");
    Mat frame = new Mat();

    while (true){
        videoCapture.read(frame);


    }
}
}

错误：

#
# A fatal error has been detected by the Java Runtime Environment:
#
#  SIGSEGV (0xb) at pc=0x00007fffbe7d605d, pid=922, tid=0x0000000000000307
#
# JRE version: Java(TM) SE Runtime Environment (8.0_101-b13) (build 1.8.0_101-b13)
# Java VM: Java HotSpot(TM) 64-Bit Server VM (25.101-b13 mixed mode bsd-amd64 compressed oops)
# Problematic frame:
# C  [libobjc.A.dylib+0x705d]  objc_msgSend+0x1d
#
# Failed to write core dump. Core dumps have been disabled. To enable core dumping, try "ulimit -c unlimited" before starting Java again
#
# An error report file with more information is saved as:
# /path /hs_err_pid922.log
#
# If you would like to submit a bug report, please visit:
#   http://bugreport.java.com/bugreport/crash.jsp
#

Process finished with exit code 134 (interrupted by signal 6: SIGABRT)

我按照 python 教程编写了这段代码

import numpy as np
import cv2

cap = cv2.VideoCapture(0)

while 1:
    ret, img = cap.read()
    gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
    cv2.imshow('THE CAMERA FOR FACE AND EYE',img)
    k = cv2.waitKey(30) & 0xff
    if k == 27:
        break


cap.release()
cv2.destroyAllWindows()

它奏效了。

请帮帮我。我该如何解决这个问题。另一方面，我在网上找不到足够的解释清楚的材料。请给我一些好的资源。提前谢谢

Answer 1

您的代码的问题是您试图通过使用videocapture.open("the video") 再次打开 VideoCapture 而不传递文件的类型。您从网络摄像头捕获流的代码应该是：

import org.opencv.core.Core;
import org.opencv.core.Mat;
import org.opencv.videoio.VideoCapture;


public class WebCam {
public static void main(String[] args) {
System.loadLibrary(Core.NATIVE_LIBRARY_NAME);

VideoCapture videoCapture = new VideoCapture(0);
Mat frame = new Mat();

while (true){
    videoCapture.read(frame);
    showResult(frame);
}
} 

public static void showResult(Mat img) {
Imgproc.resize(img, img, new Size(640, 480));
MatOfByte matOfByte = new MatOfByte();
Highgui.imencode(".jpg", img, matOfByte);
byte[] byteArray = matOfByte.toArray();
BufferedImage bufImage = null;
try {
    InputStream in = new ByteArrayInputStream(byteArray);
    bufImage = ImageIO.read(in);
    JFrame frame = new JFrame();
    frame.getContentPane().add(new JLabel(new ImageIcon(bufImage)));
    frame.pack();
    frame.setVisible(true);
} catch (Exception e) {
    e.printStackTrace();
}
}
}

为了显示框架，您需要使用提到的解决方案here，因为还没有 Java highgui 包装器。 我希望这会有所帮助。