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In the Open cv Tutorial1, i just want to use some Imgproc functions to deal with the input camera images on the callback function: public Mat onCameraFrame(CvCameraViewFrame inputFrame) . I just added this sentences at onCameraFram:

public Mat onCameraFrame(CvCameraViewFrame inputFrame) {    
    MatOfPoint corners = null;
    mRgba = inputFrame.rgba();
    mGray= inputFrame.gray();
    Imgproc.goodFeaturesToTrack(mGray, corners, 10, 0.5, 0.5);
return mRgba;  
}

But when it runs to Imgpro.goodFeaturesToTrack, the error jump out on my cell phone and the program stops.

This is the error

03-21 11:08:32.519: E/Trace(8212): error opening trace file: No such file or directory (2)
03-21 11:08:32.972: E/OpenCV_for_Tegra(8212): Tegra Version detected: 0
03-21 11:08:33.534: E/AndroidRuntime(8212): FATAL EXCEPTION: Thread-405
03-21 11:08:33.534: E/AndroidRuntime(8212): java.lang.NullPointerException
03-21 11:08:33.534: E/AndroidRuntime(8212):     at org.opencv.imgproc.Imgproc.goodFeaturesToTrack(Imgproc.java:6486)
03-21 11:08:33.534: E/AndroidRuntime(8212):     at org.opencv.samples.tutorial1.Tutorial1Activity.onCameraFrame(Tutorial1Activity.java:161)
03-21 11:08:33.534: E/AndroidRuntime(8212):     at org.opencv.android.CameraBridgeViewBase.deliverAndDrawFrame(CameraBridgeViewBase.java:376)
03-21 11:08:33.534: E/AndroidRuntime(8212):     at org.opencv.android.JavaCameraView$CameraWorker.run(JavaCameraView.java:294)
03-21 11:08:33.534: E/AndroidRuntime(8212):     at java.lang.Thread.run(Thread.java:856)

Does anybody know what might be wrong?

mjkaufer
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user3448137
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1 Answers1

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well. here's your 'null pointer' :

MatOfPoint corners = null;

what you needed, was:

MatOfPoint corners = new MatOfPoint();
berak
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