Shulz's profile - activity

How does submat perform in comparison to rect? In what way can we use them differently?

That format is so messed up !

I am new to Opencv and java I'm trying to understand the onTouch method of Coloblobdetection of OpenCv. So far I have managed to define the purpose of some line and the other methods but I wont go to the step-by-step. If someone kindly at least help me understand the function of the lines below (specially the //????); what it does or what is its purpose ? I won't ask for the step-by-step but if someone could provide it is also fine.

    startTime = System.currentTimeMillis();// <- start elapsed time millisec;

    int cols = mRgba.cols();          //gets the columns of pixels depending of resolution
    int rows = mRgba.rows();          //gets the rows of pixels depending of resolution

    //Toast.makeText(this,cols+" "+ rows,Toast.LENGTH_SHORT).show();

    int xOffset = (mOpenCvCameraView.getWidth() - cols) / 2; //offsets are 0; distance (displacement) between the beginning of the object and a given element or point x,y axis
    int yOffset = (mOpenCvCameraView.getHeight() - rows) / 2;

    //Toast.makeText(this,"X offset "+xOffset+" Y offset "+yOffset,Toast.LENGTH_SHORT).show(); //<-- offset is always 0

    int x = (int)event.getX() - xOffset;
    int y = (int)event.getY() - yOffset;

    //Toast.makeText(this,"X-axis: "+x+" Y-axis: "+y, Toast.LENGTH_SHORT).show();

    Log.i(TAG, "Touch image coordinates: (" + x + ", " + y + ")");

    if ((x < 0) || (y < 0) || (x > cols) || (y > rows)) return false; // <-- ?????

    Rect touchedRect = new Rect();

    touchedRect.x = (x>4) ? x-4 : 0;        //????
    touchedRect.y = (y>4) ? y-4 : 0;        

    touchedRect.width = (x+4 < cols) ? x + 4 - touchedRect.x : cols - touchedRect.x; //????
    touchedRect.height = (y+4 < rows) ? y + 4 - touchedRect.y : rows - touchedRect.y;

    Mat touchedRegionRgba = mRgba.submat(touchedRect); //???

    Mat touchedRegionHsv = new Mat();
    Imgproc.cvtColor(touchedRegionRgba, touchedRegionHsv, Imgproc.COLOR_RGB2HSV_FULL);

    // Calculate average color of touched region
    mBlobColorHsv = Core.sumElems(touchedRegionHsv);
    int pointCount = touchedRect.width*touchedRect.height;
    for (int i = 0; i < mBlobColorHsv.val.length; i++)
        mBlobColorHsv.val[i] /= pointCount;

    mBlobColorRgba = converScalarHsv2Rgba(mBlobColorHsv);

    Log.i(TAG, "Touched rgba color: (" + mBlobColorRgba.val[0] + ", " + mBlobColorRgba.val[1] +
            ", " + mBlobColorRgba.val[2] + ", " + mBlobColorRgba.val[3] + ")");

    mDetector.setHsvColor(mBlobColorHsv);

    Imgproc.resize(mDetector.getSpectrum(), mSpectrum, SPECTRUM_SIZE);

    mIsColorSelected = true;

    touchedRegionRgba.release();
    touchedRegionHsv.release();

I heard about CvType.CV_8UC4 from this site which is unsiged. What is the purpose or difference with this? How does both work?

How do I take a picture with color blob detection? I seem to have some problem merging camerabridgeviewbase and javacameraview, that is why I cannot make the capturing work.

What I wanted to happen is while the colorblobdetection is displaying its result I will have the capacity to take an image out of it. Similar to this [photo] but this photo is made by taking a screenshot using(power+vol down). (https://www.imageupload.co.uk/image/BKjv)

My simplest question is that, is there a possibility of taking a screenshot of the phone using opencv? (the code there is plain android api but does not display the exact image)

How do I make a screenshot using Opencv (android) and convert it to an Image. I myself have made a code for screenshot see link here. The output of this image is black which is not I wanted. Is there also a possibility of using a mat here?

public void camera_b(View v)
{
    String path = Environment.getExternalStorageDirectory().toString() + "/" + "hellp.jpg";

    v = getWindow().getDecorView().getRootView();
    v.setDrawingCacheEnabled(true);
    Bitmap bitmap = Bitmap.createBitmap(v.getDrawingCache());
    v.setDrawingCacheEnabled(false);

    OutputStream out = null;
    File imageFile = new File(path);

    try {
        out = new FileOutputStream(imageFile);
        // choose JPEG format
        bitmap.compress(Bitmap.CompressFormat.JPEG, 90, out);
        out.flush();
    } catch (FileNotFoundException e) {
        // manage exception
    } catch (IOException e) {
        // manage exception
    } finally {

        try {
            if (out != null) {
                out.close();
            }

        } catch (Exception exc) {
        }

    }
}