问题描述
我有一个来自https://ratiler.wordpress.com/2014/09/08/detection-de-mouvement-avec-javacv/的示例代码,与使用nu.pattern.OpenCV.loadShared();
将打开的cv库加载到静态块中的差别很小:
import java.awt.image.BufferedImage;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import org.opencv.core.CvType;
import org.opencv.core.Mat;
import org.opencv.core.MatOfByte;
import org.opencv.core.Size;
import org.opencv.imgcodecs.Imgcodecs;
import org.opencv.videoio.VideoCapture;
import org.opencv.imgproc.Imgproc;
public class JavaCVPrjt01 {
static {
//System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
nu.pattern.OpenCV.loadShared();
}
public static void main(String[] args) {
JFrame jframe = new JFrame("HUMAN MOTION DETECTOR FPS");
jframe.setDefaultCloSEOperation(JFrame.EXIT_ON_CLOSE);
JLabel vidpanel = new JLabel();
jframe.setContentPane(vidpanel);
jframe.setSize(1280,720) ;
jframe.setVisible(true);
Mat frame = new Mat();
Mat outerBox = new Mat();
Size sz = new Size(1280,720);
VideoCapture camera = new VideoCapture("D:/Downloads/video4.mp4");
while (true) {
if (camera.read(frame)) {
Imgproc.resize(frame,frame,sz );
outerBox = new Mat(frame.size(),CvType.CV_8UC1);
Imgproc.cvtColor(frame,outerBox,Imgproc.COLOR_BGR2GRAY);
Imgproc.GaussianBlur(outerBox,new Size(3,3),0);
ImageIcon image = new ImageIcon(Mat2bufferedImage(outerBox));
vidpanel.setIcon(image);
vidpanel.repaint();
}
}
}
public static BufferedImage Mat2bufferedImage(Mat image) {
MatOfByte bytemat = new MatOfByte();
Imgcodecs.imencode(".jpg",image,bytemat);
byte[] bytes = bytemat.toArray();
InputStream in = new ByteArrayInputStream(bytes);
BufferedImage img = null;
try {
img = ImageIO.read(in);
} catch (IOException e) {
// Todo Auto-generated catch block
e.printstacktrace();
}
return img;
}
}
,当然,还添加了所需的依赖项:
<dependency>
<groupId>org.bytedeco.javacpp-presets</groupId>
<artifactId>opencv</artifactId>
<version>3.2.0-1.3</version>
</dependency>
<dependency>
<groupId>org.openpnp</groupId>
<artifactId>opencv</artifactId>
<version>3.2.0-1</version>
</dependency>
因此,代码是在执行之前
VideoCapture camera = new VideoCapture("D:/Downloads/video4.mp4");
它挂在什么地方,我不知道那里的JNI级别有什么问题。
解决方法
这是一个许可问题,因此无法将ffmpeg包括在内
<dependency>
<groupId>org.openpnp</groupId>
<artifactId>opencv</artifactId>
<version>3.2.0-1</version>
</dependency>
(它似乎发生在所有版本中,我都尝试过maven中的所有可用功能)
https://github.com/openpnp/opencv/issues/55
UPD。
因此仍然需要显式加载dll。就我而言
static {
//System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
System.load("D:\\Downloads\\opencv\\build\\java\\x64\\opencv_java2411.dll");
System.load("D:\\Downloads\\opencv\\build\\x64\\vc12\\bin\\opencv_ffmpeg2411_64.dll");
}
opencv_java
和opencv_ffmpeg
的显式负载可以解决问题。在没有显式加载opencv_ffmpeg
的情况下,VideoCapture's
.read(frame)
总是返回false,而未提及任何丢失的本机ffmpeg
依赖性问题。
pom.xml
中必需的java依赖项是:
<dependency>
<groupId>org.bytedeco.javacpp-presets</groupId>
<artifactId>opencv</artifactId>
<version>2.4.11-0.11</version>
</dependency>
<dependency>
<groupId>org.openpnp</groupId>
<artifactId>opencv</artifactId>
<version>2.4.11-2</version>
</dependency>
(请问我是否已将opencv版本降级了)