Collectives™ on Stack Overflow

Find centralized, trusted content and collaborate around the technologies you use most.

Teams

Q&A for work

Connect and share knowledge within a single location that is structured and easy to search.

I need capture a video stream from my USB webcam, for this i use Opencv 2.4.6 for developing in Java. I follow the steps listed in here

I add the "C:\opencv\build\java\x64" dir to my System PATH and include the "opencv-246.jar" file into my libraries on ECLIPSE. When y run the explame

import org.opencv.core.Core;
import org.opencv.core.CvType;
import org.opencv.core.Mat;
public class Main {
    public static void main(String[] args) {
        System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
        Mat m  = Mat.eye(3, 3, CvType.CV_8UC1);
        System.out.println("m = " + m.dump());
i get 
m = [1, 0, 0;
  0, 1, 0;
  0, 0, 1]
OK =)
but when i run 
import org.opencv.highgui.VideoCapture;
public class Main {
    public static void main(String[] args) {
        VideoCapture vc = new VideoCapture(0);
        if(vc.isOpened()){
            System.out.println("Works!");
i get 
Exception in thread "main" java.lang.UnsatisfiedLinkError: org.opencv.highgui.VideoCapture.n_VideoCapture(I)J
    at org.opencv.highgui.VideoCapture.n_VideoCapture(Native Method)
    at org.opencv.highgui.VideoCapture.<init>(VideoCapture.java:113)
    at Main.main(Main.java:5)
i add all the routes containes in:
  
C:\opencv\build\x64\vc10
one by one,but doesn`t work.
Finally i create a variable called OPENCV_DIR with C:\opencv\build\x64\vc10 but still getting UnsatisfiedLinkError.
PLEASE HELP ME!
in your second example , you skipped this line
 System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
so the opencv libs werent loaded, UnsatisfiedLinkError, etc...
[edit]:
thanks to  @Jishnu Prathap for highlighting the java.library path issue, if you run into problems setting that, you can still try to use an absolute path to the java wrapper so/dll/dylib like:
 System.load("/path to/our/java_wrapper");
                static{ System.loadLibrary(Core.NATIVE_LIBRARY_NAME); }  to make sure it's loaded one time..
– Marwen Trabelsi
                Feb 23, 2014 at 22:21
        OpenCV.loadLocally();
        Mat mat = Mat.eye( 3, 3, CvType.CV_8UC1 );
        System.out.println( "mat = " + mat.dump() );
For general users using opencv3.x:
HighGUI module does not exist anymore in Java for opencv 3.0 and above.
import org.opencv.videoio.VideoCapture;
instead of 
import org.opencv.highgui.VideoCapture;
videoio includes VideoCapture, VideoWriter.
Similarly:
imgcodecs includes imread/imwrite and friends
Example:
Highgui.imread(fileName)
 Imgcodecs.imread(fileName)
So, I was having this problem too and I did what you all suggested, it worked fine in my x64 windows, but in a x86 couldn't make it work.
At last I found a solution by changing:
VideoCapture capture = new VideoCapture(0);
    VideoCapture capture = new VideoCapture();
    capture.open("resources/vid.MP4");
I don't know why this worked but I hope it may help somebody with my same problem.
I tried a lot of tutorials online for the resolution, only one of them have helped me.
There are two steps that are different in this method,
Firstly, while importing the java project from Opencv SDK into the Android studio, make sure to uncheck all the checkboxes presented in the import dialog.
Secondly, make sure you import the OpenCV.mk file that is in the native/jdk of the SDK..
The System.loadLibrary() seems to return true after this, which was a huge relief for me as it took me several hours to figure this out
Here's the link to the tutorial that helped me
https://medium.com/@rdeep/android-opencv-integration-without-opencv-manager-c259ef14e73b
        
Thanks for contributing an answer to Stack Overflow!
Please be sure to answer the question. Provide details and share your research!
But avoid …
Asking for help, clarification, or responding to other answers.
Making statements based on opinion; back them up with references or personal experience.
To learn more, see our tips on writing great answers.