# Revision history [back]

### set android CvCameraViewFrame transparent

Hello everybody

My target is to make an android application with openCV, that has a camera preview. In this preview i want to filter out a color range and set it transparent. For example, I want to filter out green and set it to transparent.

Question 1: is it possible to make parts of the CvCameraViewFrame transparent?

In the background of my application, (behind the camerapreview) is a static picture that should come through the transparent part of the camera preview.

Question 2: with respect to these answers: sustract color from Mat why is following code not working?

android activity:

    public Mat onCameraFrame(CvCameraViewFrame inputFrame){
mRgba = inputFrame.rgba();
return mRgba;
}
public native void RemovePink( long matAddrRgba);


and the jni:

JNIEXPORT void JNICALL
JNIEXPORT void JNICALL Java_org_opencv_samples_tutorial2_Tutorial2Activity_RemovePink(JNIEnv*, jobject, jlong addrRgba){

Mat alpha;
inRange(mRgba , Scalar(0,0,250),  Scalar(0,0,255),alpha);
bitwise_not(alpha,alpha);

//split source
Mat bgr[4];
split(mRgba ,bgr);

//Merge to final image including alpha
Mat tmp[4] = { bgr[0],bgr[1],bgr[2],alpha};
merge(mRgba ,4,dst);
}
}


thanks in advance for every kind of help!

### set android CvCameraViewFrame transparent

Hello everybody

My target is to make an android application with openCV, that has a camera preview. In this preview i want to filter out a color range and set it transparent. For example, I want to filter out green and set it to transparent.

Question 1: is it possible to make parts of the CvCameraViewFrame transparent?

In the background of my application, (behind the camerapreview) is a static picture that should come through the transparent part of the camera preview.

For example, I want to filter out green and set it to transparent.

Question 1: is it possible to make parts of the CvCameraViewFrame transparent?

Question 2: with respect to these answers: sustract color from Mat why is following code not working?

android activity:

    public Mat onCameraFrame(CvCameraViewFrame inputFrame){
mRgba = inputFrame.rgba();
return mRgba;
}
public native void RemovePink( long matAddrRgba);


and the jni:

JNIEXPORT void JNICALL
JNIEXPORT void JNICALL Java_org_opencv_samples_tutorial2_Tutorial2Activity_RemovePink(JNIEnv*, jobject, jlong addrRgba){

Mat alpha;
inRange(mRgba , Scalar(0,0,250),  Scalar(0,0,255),alpha);
bitwise_not(alpha,alpha);

//split source
Mat bgr[4];
split(mRgba ,bgr);

//Merge to final image including alpha
Mat tmp[4] = { bgr[0],bgr[1],bgr[2],alpha};
merge(mRgba ,4,dst);
}
}


thanks in advance for every kind of help!

### set color transparent in the android CvCameraViewFrame transparentcamera preview

Hello everybody

My target is to make an android application with openCV, that has a camera preview. In this preview i want to filter out a color range and set it transparent.

In the background of my application, (behind the camerapreview) is a static picture that should come through the transparent part of the camera preview.

For example, I want to filter out green and set it to transparent.

Question 1: is it possible to make parts of the CvCameraViewFrame transparent?

Question 2: with respect to these answers: sustract color from Mat why is following code not working?

android activity:

    public Mat onCameraFrame(CvCameraViewFrame inputFrame){
mRgba = inputFrame.rgba();
return mRgba;
}
public native void RemovePink( long matAddrRgba);


and the jni:

JNIEXPORT void JNICALL
JNIEXPORT void JNICALL Java_org_opencv_samples_tutorial2_Tutorial2Activity_RemovePink(JNIEnv*, jobject, jlong addrRgba){

Mat alpha;
inRange(mRgba , Scalar(0,0,250),  Scalar(0,0,255),alpha);
bitwise_not(alpha,alpha);

//split source
Mat bgr[4];
split(mRgba ,bgr);

//Merge to final image including alpha
Mat tmp[4] = { bgr[0],bgr[1],bgr[2],alpha};
merge(mRgba ,4,dst);
}
}


thanks in advance for every kind of help!