CODEWITHSUNDEEP
javaandroidopencvgaussianblur
Srinivas Nahak
Srinivas Nahak

Reputation: 1866

How to apply gussian blur to the picture in openCV?

I'm a complete beginner in openCV so please do excuse me if my question is foolish. Basically I'm trying to apply gussianBlur in openCv but it's showing a strange error I don't understand why ?

Code:

Mat tmp = new Mat (bitmap.getWidth(), bitmap.getHeight(), CvType.CV_8UC4);
Utils.bitmapToMat(bitmap, tmp);
//Imgproc.cvtColor(tmp, tmp, Imgproc.COLOR_RGB2HSV_FULL);
Imgproc.GaussianBlur(tmp,tmp,new org.opencv.core.Size(2,2),0,0);
Utils.matToBitmap(tmp,bitmap);
imgView.setImageBitmap(null);
imgView.setImageBitmap(bitmap);

Error:

CvException [org.opencv.core.CvException: cv::Exception: /hdd2/buildbot/slaves/slave_ardbeg1/50-SDK/opencv/modules/imgproc/src/smooth.cpp:816: error: (-215) ksize.width > 0 && ksize.width % 2 == 1 && ksize.height > 0 && ksize.height % 2 == 1 in function cv::Ptr<cv::FilterEngine> cv::createGaussianFilter(int, cv::Size, double, double, int)]
    at org.opencv.imgproc.Imgproc.GaussianBlur_1(Native Method)
    at org.opencv.imgproc.Imgproc.GaussianBlur(Imgproc.java:533)
    at opengl.community.myopencvexample.MainActivity$3.onClick(MainActivity.java:82)
    at android.view.View.performClick(View.java:4478)
    at android.view.View$PerformClick.run(View.java:18698)
    at android.os.Handler.handleCallback(Handler.java:733)
    at android.os.Handler.dispatchMessage(Handler.java:95)
    at android.os.Looper.loop(Looper.java:149)
    at android.app.ActivityThread.main(ActivityThread.java:5257)
    at java.lang.reflect.Method.invokeNative(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:515)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:609)
    at dalvik.system.NativeStart.main(Native Method)

Upvotes: 4

Views: 3375

Answers (1)

Nabin Bhandari
Nabin Bhandari

Reputation: 16389

Documentation of the method GaussianBlur: https://docs.opencv.org/java/2.4.9/org/opencv/imgproc/Imgproc.html#GaussianBlur(org.opencv.core.Mat,%20org.opencv.core.Mat,%20org.opencv.core.Size,%20double,%20double)

public static void GaussianBlur(Mat src, Mat dst, Size ksize, double sigmaX, double sigmaY)

ksize - Gaussian kernel size. ksize.width and ksize.height can differ but they both must be positive and odd. Or, they can be zero's and then they are computed from sigma*.

You are passing 2, 2 for kernel size, which are not odd.

Use something like this:

Imgproc.GaussianBlur(tmp, tmp, new Size(3, 3), 0, 0);

Upvotes: 5

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