Android Multithreading - android

I have a piece of code that is removing bitmap background, at first the code was taking about 40s> to remove each bitmap background but I optimized to about 12son a hauwei y320 -u30 with quadcore 1.3ghz each and 6s on Galaxy s3 Quadcore although this is pretty good compared to the first product it is not good enough I want it start ranging in about 2s to 3s for the huawei due to the fact that the base user will probably have a low end device, I am using an async task with fixed fixedthreadpool of 2 and thread priority of Process.setThreadPriority(Process.THREAD_PRIORITY_BACKGROUND +
Process.THREAD_PRIORITY_MORE_FAVORABLE) but I was wondering, I know multi threading is the ability of running multiple tasks per single time frame but isnt there a way I can run 2 or 3 threads on one task, for example in my case run the threads on my background removal code, am sure this can yield better performance due to the fact that at the time am running this code there is no other thread within my app that is also running, I have all resources per run time of my code, I looked up online but I cannot find anything related to that, below is the my code:
public class ImageBackgrndRemover extends AppCompatActivity {
private BaseLoaderCallback mLoaderCallback = new BaseLoaderCallback(this) {
#Override
public void onManagerConnected(int status) {
switch (status) {
case LoaderCallbackInterface.SUCCESS:
{
Log.i(TAG, "OpenCV loaded successfully");
//instantia
if(!alreadyRun) {
BackgroundRemover remover = null;
if(remover == null)
{
remover = new BackgroundRemover();
remover.executeOnExecutor(AsyncTask.DUAL_THREAD_EXECUTOR);
}
}
} break;
default:
{
super.onManagerConnected(status);
} break;
}
}
};
private LoadingAnimation add;
ImageView iv;
Scalar color;
Mat dst;
private boolean alreadyRun;
public static final String TAG = "Grabcut demo";
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_image_backgrnd_remover);
iv = (ImageView) this.findViewById(R.id.imagePreview);
}
private int calculatePercentage(int percentage, int target)
{
int k = (int)(target*(percentage/100.0f));
return k;
}
private Bitmap backGrndErase()
{
color = new Scalar(255, 0, 0, 255);
dst = new Mat();
Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.myshirt);
Log.d(TAG, "bitmap: " + bitmap.getWidth() + "x" + bitmap.getHeight());
bitmap = ResizeImage.getResizedBitmap(bitmap, calculatePercentage(40, bitmap.getWidth()), calculatePercentage(40, bitmap.getHeight()));
// Bitmap bitmap2 = ImageCornerMoulder.getRoundedCornerBitmap(bmp, calculatePercentage(5, bmp.getHeight()));
bitmap = bitmap.copy(Bitmap.Config.ARGB_8888, true);
Log.d(TAG, "bitmap 8888: " + bitmap.getWidth() + "x" + bitmap.getHeight());
//GrabCut part
Mat img = new Mat();
Utils.bitmapToMat(bitmap, img);
Log.d(TAG, "img: " + img);
int r = img.rows();
int c = img.cols();
Point p1 = new Point(c/10, r/10);
Point p2 = new Point(c-c/10, r-r/10);
int border = 20;
int border2 = border + border;
Rect rect2 = new Rect(border,border,img.cols()-border2,img.rows()-border2);
Rect rect = new Rect(p1,p2);
Log.d(TAG, "rect: " + rect);
Mat mask = new Mat();
debugger(""+mask.type());
mask.setTo(new Scalar(125));
Mat fgdModel = new Mat();
fgdModel.setTo(new Scalar(255, 255, 255));
Mat bgdModel = new Mat();
bgdModel.setTo(new Scalar(255, 255, 255));
Mat imgC3 = new Mat();
Imgproc.cvtColor(img, imgC3, Imgproc.COLOR_RGBA2RGB);
Log.d(TAG, "imgC3: " + imgC3);
Log.d(TAG, "Grabcut begins");
Imgproc.grabCut(imgC3, mask, rect2, bgdModel, fgdModel, 2, Imgproc.GC_INIT_WITH_RECT);
Mat source = new Mat(1, 1, CvType.CV_8U, new Scalar(3.0));
Core.compare(mask, source, mask, Core.CMP_EQ);
Mat foreground = new Mat(img.size(), CvType.CV_8UC3, new Scalar(255, 255, 255));
img.copyTo(foreground, mask);
Imgproc.rectangle(img, p1, p2, color);
Mat background = new Mat();
try {
background = Utils.loadResource(getApplicationContext(),
R.drawable.blackcolor );
} catch (IOException e) {
e.printStackTrace();
}
Mat tmp = new Mat();
Imgproc.resize(background, tmp, img.size());
background = tmp;
Mat tempMask = new Mat(foreground.size(), CvType.CV_8UC1, new Scalar(255, 255, 255));
Imgproc.cvtColor(foreground, tempMask, 6/* COLOR_BGR2GRAY */);
//Imgproc.threshold(tempMask, tempMask, 254, 255, 1 /* THRESH_BINARY_INV */);
Mat vals = new Mat(1, 1, CvType.CV_8UC3, new Scalar(0.0));
dst = new Mat();
background.setTo(vals, tempMask);
Imgproc.resize(foreground, tmp, mask.size());
foreground = tmp;
Core.add(background, foreground, dst, tempMask);
Log.d(TAG, "Convert to Bitmap");
//removing blackbaground started
/***
Mat tmp2 = new Mat();
Mat alpha = new Mat();
Imgproc.cvtColor(dst, tmp2, Imgproc.COLOR_BGR2GRAY);
Imgproc.threshold(tmp2, alpha, 100, 255, Imgproc.THRESH_BINARY);
List<Mat> rgb = new ArrayList<Mat>(3);
Core.split(dst, rgb);
List<Mat> rgba = new ArrayList<Mat>(4);
rgba.add(rgb.get(0));
rgba.add(rgb.get(1));
rgba.add(rgb.get(2));
rgba.add(alpha);
Core.merge(rgba, dst);
Bitmap output = Bitmap.createBitmap(dst.width(), dst.height(), Bitmap.Config.ARGB_8888);
Utils.matToBitmap(dst, output);
***/
//removing back ended
Utils.matToBitmap(dst, bitmap);
//release MAT part
img.release();
imgC3.release();
mask.release();
fgdModel.release();
bgdModel.release();
alreadyRun = true;
return bitmap;
}
private void showLoadingIndicator()
{
android.support.v4.app.FragmentManager fm = getSupportFragmentManager();
add = LoadingAnimation.newInstance("b");
add.show(fm, "");
add.setCancelable(false);
}
private void dismissLoadingIndicator()
{
try {
add.dismiss();
}catch (Exception e)
{
e.printStackTrace();
}
}
private class BackgroundRemover extends AsyncTask<Void, Void, Bitmap>
{
#Override
protected void onPreExecute()
{
showLoadingIndicator();
}
#Override
protected Bitmap doInBackground(Void... voids) {
Process.setThreadPriority(Process.THREAD_PRIORITY_BACKGROUND +
Process.THREAD_PRIORITY_MORE_FAVORABLE);
try{
return backGrndErase();
}catch (Exception e)
{
System.err.println("Failed to remove background");
}
return null;
}
#Override
protected void onPostExecute(Bitmap bitmap) {
// iv.setBackgroundResource(R.drawable.blackcolor);
iv.setImageBitmap(bitmap);
dismissLoadingIndicator();
}
}
#Override
public void onResume()
{
super.onResume();
if (!OpenCVLoader.initDebug()) {
Log.d(TAG, "Internal OpenCV library not found. Using OpenCV Manager for initialization");
OpenCVLoader.initAsync(OpenCVLoader.OPENCV_VERSION_3_0_0, this, mLoaderCallback);
} else {
Log.d(TAG, "OpenCV library found inside package. Using it!");
mLoaderCallback.onManagerConnected(LoaderCallbackInterface.SUCCESS);
}
}
private static Bitmap makeBlackTransparent(Bitmap image) {
// convert image to matrix
Mat src = new Mat(image.getWidth(), image.getHeight(), CvType.CV_8UC4);
Utils.bitmapToMat(image, src);
// init new matrices
Mat dst = new Mat(image.getWidth(), image.getHeight(), CvType.CV_8UC4);
Mat tmp = new Mat(image.getWidth(), image.getHeight(), CvType.CV_8UC4);
Mat alpha = new Mat(image.getWidth(), image.getHeight(), CvType.CV_8UC4);
// convert image to grayscale
Imgproc.cvtColor(src, tmp, Imgproc.COLOR_BGR2GRAY);
// threshold the image to create alpha channel with complete transparency in black background region and zero transparency in foreground object region.
Imgproc.threshold(tmp, alpha, 100, 255, Imgproc.THRESH_BINARY);
// split the original image into three single channel.
List<Mat> rgb = new ArrayList<Mat>(3);
Core.split(src, rgb);
// Create the final result by merging three single channel and alpha(BGRA order)
List<Mat> rgba = new ArrayList<Mat>(4);
rgba.add(rgb.get(0));
rgba.add(rgb.get(1));
rgba.add(rgb.get(2));
rgba.add(alpha);
Core.merge(rgba, dst);
// convert matrix to output bitmap
Bitmap output = Bitmap.createBitmap(image.getWidth(), image.getHeight(), Bitmap.Config.ARGB_8888);
Utils.matToBitmap(dst, output);
return output;
}
public void debugger(String s){
Log.v("", "########### " + s);
}
}

Related

ADD and subtract with openCV

I'm using opencv 3.0.0 on android-studio, i need to convert a RGB image to YIQ so i have to do some adds and subtracts equations. i used the Core.Split of openCV to take the Red , Green, and blue channel from the RGB image. Then i used this channels to calculte the YIQ image using this equations : equation. after the test of my appp i got this Error : A/libc: Fatal signal 11 (SIGSEGV), code 1 (SEGV_MAPERR), fault addr 0x19b in tid 27631 (orstackoverflow), pid 27631 (orstackoverflow)
And this is my code
public class MainActivity extends AppCompatActivity {
private static final String TAG = "3:qinQctivity";
Button button;
ImageView imageView;
ArrayList<Mat> RGB = new ArrayList<Mat>(3);
ArrayList<Mat> YIQ = new ArrayList<Mat>(3);
Mat newImage;
Mat Blue,Green,Red,I,Y,Q,B,X,D,W;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
button = findViewById(R.id.button);
imageView = findViewById(R.id.image);
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
if (!OpenCVLoader.initDebug()) {
OpenCVLoader.initAsync(OpenCVLoader.OPENCV_VERSION_3_0_0, getApplicationContext(), baseLoaderCallback);
} else {
baseLoaderCallback.onManagerConnected(LoaderCallbackInterface.SUCCESS);
}
}
});
}
BaseLoaderCallback baseLoaderCallback = new BaseLoaderCallback(this) {
#Override
public void onManagerConnected(int status) {
super.onManagerConnected(status);
if (status == LoaderCallbackInterface.SUCCESS) {
try {
Y = new Mat();
Q = new Mat();
I = new Mat();
X = new Mat();
newImage = Utils.loadResource(getApplicationContext(), R.drawable.retinalimage, CvType.CV_32FC3);
Core.split(newImage, RGB);
Blue = RGB.get(0);
Red = RGB.get(1);
Green = RGB.get(2);
B = new Mat(); // result
D = new Mat(); // result
W = new Mat(); // result
/*working on Y channel*/
Scalar alpha_Y = new Scalar(0.299); // the factor
Scalar alpha1_Y = new Scalar(0.587); // the factor
Scalar alpha2_Y = new Scalar(0.114); // the factor
Core.multiply(Red,alpha_Y, B);
Core.multiply(Green,alpha1_Y,D);
Core.multiply(Blue,alpha2_Y,W);
Core.add(B,D,Y);
Log.i(TAG, "onManagerConnected: "+ Y.toString());
Core.add(Y,W,Y);
/*I = 0.211 * Red - 0.523 * Green + 0.312 * Blue;*/
Mat Z = new Mat(); // result
Mat P = new Mat(); // result
Mat O = new Mat(); // result
/*working on I channel*/
Scalar alpha_I = new Scalar(0.211); // the factor
Scalar alpha1_I = new Scalar(0.523); // the factor
Scalar alpha2_I = new Scalar(0.312); // the factor
Core.multiply(Red,alpha_I,Z);
Core.multiply(Green,alpha1_I,P);
Core.multiply(Blue,alpha2_I,O);
Core.add(Z,P,I);
Core.add(I,O,I);
/*working on Q channel*/
/*Q = 0.596 * Red - 0.274 * Green - 0.322 * Blue;*/
Mat V = new Mat();
Mat W = new Mat();
Mat N = new Mat();
Scalar alpha_Q = new Scalar(0.596); // the factor
Scalar alpha1_Q = new Scalar(0.274); // the factor
Scalar alpha2_Q = new Scalar(0.322); // the factor
Core.multiply(Red,alpha_Q,V);
Core.multiply(Green,alpha1_Q,W);
Core.multiply(Blue,alpha2_Q,N);
Core.subtract(V,W,Q);
Core.subtract(Q,N,Y);
YIQ.add(Y);
YIQ.add(I);
YIQ.add(Q);
Core.merge(YIQ,X);
showImage(X);
} catch(IOException e){
e.printStackTrace();
}
}
}
} ;
void showImage (Mat y){
Bitmap bm = Bitmap.createBitmap(y.width(), y.height(), Bitmap.Config.ARGB_8888);
Utils.matToBitmap(y, bm);
imageView.setImageBitmap(bm);
}
You are not allocating memory for the mats B,D,W,Z,P,O,.... You need to get the size of the original RGB Matrices and pass the size to the new matrix constructors. According to OpenCV documentation for the multiply function:
Parameters:
src1 - First source array.
src2 - Second source array of the same size and the same type as src1.
dst - Destination array of the same size and type as src1.
(highlights mine)

Opencv4Android grabcut's output image has different colors(brighter colors) than the input image

public class Grabcut extends Activity {
ImageView iv;
Bitmap bitmap;
Canvas canvas;
Scalar color = new Scalar(255, 0, 0, 255);
Point tl, br;
int counter;
Bitmap bitmapResult, bitmapBackground;
Mat dst = new Mat();
final String pathToImage = Environment.getExternalStorageDirectory()+"/gcut.png";
public static final String TAG = "Grabcut demo";
static {
if (!OpenCVLoader.initDebug()) {
// Handle initialization error
}
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.grabcut_main);
iv = (ImageView) this.findViewById(R.id.imageView);
Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.grabcut);
Log.d(TAG, "bitmap: " + bitmap.getWidth() + "x" + bitmap.getHeight());
bitmap = bitmap.copy(Bitmap.Config.ARGB_8888, true);
Log.d(TAG, "bitmap 8888: " + bitmap.getWidth() + "x" + bitmap.getHeight());
//GrabCut part
Mat img = new Mat();
Utils.bitmapToMat(bitmap, img);
Log.d(TAG, "img: " + img);
int r = img.rows();
int c = img.cols();
Point p1 = new Point(c/5, r/5);
Point p2 = new Point(c-c/5, r-r/8);
Rect rect = new Rect(p1,p2);
//Rect rect = new Rect(50,30, 100,200);
Log.d(TAG, "rect: " + rect);
Mat mask = new Mat();
debugger(""+mask.type());
mask.setTo(new Scalar(125));
Mat fgdModel = new Mat();
fgdModel.setTo(new Scalar(255, 255, 255));
Mat bgdModel = new Mat();
bgdModel.setTo(new Scalar(255, 255, 255));
Mat imgC3 = new Mat();
Imgproc.cvtColor(img, imgC3, Imgproc.COLOR_RGBA2RGB);
Log.d(TAG, "imgC3: " + imgC3);
Log.d(TAG, "Grabcut begins");
Imgproc.grabCut(imgC3, mask, rect, bgdModel, fgdModel, 5, Imgproc.GC_INIT_WITH_RECT);
Mat source = new Mat(1, 1, CvType.CV_8U, new Scalar(3.0));
Core.compare(mask, source, mask, Core.CMP_EQ);
Mat foreground = new Mat(img.size(), CvType.CV_8UC3, new Scalar(255, 255, 255));
img.copyTo(foreground, mask);
Core.rectangle(img, p1, p2, color);
Mat background = new Mat();
try {
background = Utils.loadResource(getApplicationContext(),
R.drawable.wall2 );
} catch (IOException e) {
e.printStackTrace();
}
Mat tmp = new Mat();
Imgproc.resize(background, tmp, img.size());
background = tmp;
Mat tempMask = new Mat(foreground.size(), CvType.CV_8UC1, new Scalar(255, 255, 255));
Imgproc.cvtColor(foreground, tempMask, 6/* COLOR_BGR2GRAY */);
//Imgproc.threshold(tempMask, tempMask, 254, 255, 1 /* THRESH_BINARY_INV */);
Mat vals = new Mat(1, 1, CvType.CV_8UC3, new Scalar(0.0));
dst = new Mat();
background.setTo(vals, tempMask);
Imgproc.resize(foreground, tmp, mask.size());
foreground = tmp;
Core.add(background, foreground, dst, tempMask);
//convert to Bitmap
Log.d(TAG, "Convert to Bitmap");
Utils.matToBitmap(dst, bitmap);
iv.setBackgroundResource(R.drawable.wall2);
iv.setImageBitmap(bitmap);
//release MAT part
img.release();
imgC3.release();
mask.release();
fgdModel.release();
bgdModel.release();
}
public void debugger(String s){
Log.v("","########### "+s);
}
}
I had followed above tutorial.But problem is that output image I get has brighter colors than my input image. Why is that and how to solve it?
My input image is Here and output image is here.Output image is actually screenshot of my application where large one is input image and small one with black background is output image.
I finally found solution to my problem. Here is code to grab cut background of an image using Grabcut algorithm in opencv for android.
public void grabcutAlgo(Bitmap bit){
Bitmap b = bit.copy(Bitmap.Config.ARGB_8888, true);
Point tl=new Point();
Point br=new Point();
//GrabCut part
Mat img = new Mat();
Utils.bitmapToMat(b, img);
Imgproc.cvtColor(img, img, Imgproc.COLOR_RGBA2RGB);
int r = img.rows();
int c = img.cols();
Point p1 = new Point(c / 100, r / 100);
Point p2 = new Point(c - c / 100, r - r / 100);
Rect rect = new Rect(p1, p2);
//Rect rect = new Rect(tl, br);
Mat background = new Mat(img.size(), CvType.CV_8UC3,
new Scalar(255, 255, 255));
Mat firstMask = new Mat();
Mat bgModel = new Mat();
Mat fgModel = new Mat();
Mat mask;
Mat source = new Mat(1, 1, CvType.CV_8U, new Scalar(Imgproc.GC_PR_FGD));
Mat dst = new Mat();
Imgproc.grabCut(img, firstMask, rect, bgModel, fgModel, 5, Imgproc.GC_INIT_WITH_RECT);
Core.compare(firstMask, source, firstMask, Core.CMP_EQ);
Mat foreground = new Mat(img.size(), CvType.CV_8UC3, new Scalar(255, 255, 255));
img.copyTo(foreground, firstMask);
Scalar color = new Scalar(255, 0, 0, 255);
Imgproc.rectangle(img, tl, br, color);
Mat tmp = new Mat();
Imgproc.resize(background, tmp, img.size());
background = tmp;
mask = new Mat(foreground.size(), CvType.CV_8UC1,
new Scalar(255, 255, 255));
Imgproc.cvtColor(foreground, mask, Imgproc.COLOR_BGR2GRAY);
Imgproc.threshold(mask, mask, 254, 255, Imgproc.THRESH_BINARY_INV);
System.out.println();
Mat vals = new Mat(1, 1, CvType.CV_8UC3, new Scalar(0.0));
background.copyTo(dst);
background.setTo(vals, mask);
Core.add(background, foreground, dst, mask);
Bitmap grabCutImage = Bitmap.createBitmap(dst.cols(), dst.rows(), Bitmap.Config.ARGB_8888);
Bitmap processedImage = Bitmap.createBitmap(dst.cols(), dst.rows(), Bitmap.Config.RGB_565);
Utils.matToBitmap(dst, grabCutImage);
dst.copyTo(sampleImage);
imageView.setImageBitmap(grabCutImage);
firstMask.release();
source.release();
bgModel.release();
fgModel.release();
}

How to compare 2 images in android using opencv?

I am very new to android and openCV, I'M working on "Android application: plant disease Analyzer".
Below is my workflow:
1.I have static plant diseases in my gallery
2.End-user can capture an plant disease and submit to my application.
3.I want to compare the processed image with my gallery(Diseases) to get the most similar disease
Can any one tell me What will be the best algorithm to use?,
I have been searching on google but no luck,I tried with
below code snippet, which I tried using openCV :
BitmapFactory.Options bmOptions = new BitmapFactory.Options();
Bitmap camerabitmap = BitmapFactory.decodeFile(cameraimage,
bmOptions);
Bitmap galareybitmap =
BitmapFactory.decodeFile(galImage.getAbsolutePath(), bmOptions);
private double imageProcessing(Bitmap cameraimage,Bitmap
galimagebitmap,String galimagename) throws IOException {
Mat img1 = new Mat();
Utils.bitmapToMat(cameraimage, img1);
Mat img2 = new Mat();
Utils.bitmapToMat(gallimagebitmap, img2);
Imgproc.cvtColor(img1, img1, Imgproc.COLOR_RGBA2GRAY);
Imgproc.cvtColor(img2, img2, Imgproc.COLOR_RGBA2GRAY);
img1.convertTo(img1, CvType.CV_32F);
img2.convertTo(img2, CvType.CV_32F);
//Log.d("ImageComparator", "img1:"+img1.rows()+"x"+img1.cols()+" img2:"+img2.rows()+"x"+img2.cols());
Mat hist1 = new Mat();
Mat hist2 = new Mat();
MatOfInt histSize = new MatOfInt(180);
MatOfInt channels = new MatOfInt(0);
ArrayList<Mat> bgr_planes1= new ArrayList<Mat>();
ArrayList<Mat> bgr_planes2= new ArrayList<Mat>();
Core.split(img1, bgr_planes1);
Core.split(img2, bgr_planes2);
MatOfFloat histRanges = new MatOfFloat(0f, 256f);
boolean accumulate = false;
Imgproc.calcHist(bgr_planes1, channels, new Mat(), hist1, histSize, histRanges);
Core.normalize(hist1, hist1, 0, hist1.rows(), Core.NORM_MINMAX, -1, new Mat());
Imgproc.calcHist(bgr_planes2, channels, new Mat(), hist2, histSize, histRanges);
Core.normalize(hist2, hist2, 0, hist2.rows(), Core.NORM_MINMAX, -1, new Mat());
/ img1.convertTo(img1, CvType.CV_32F);
// img2.convertTo(img2, CvType.CV_32F);
hist1.convertTo(hist1, CvType.CV_32F);
hist2.convertTo(hist2, CvType.CV_32F);
return Imgproc.compareHist(hist1, hist2,3);
}
I tried with template matching also in opencv
int match_method=Imgproc.TM_CCOEFF_NORMED;
Mat temp = Imgcodecs.imread(tempim,Imgcodecs.CV_LOAD_IMAGE_GRAYSCALE );
Mat img = Imgcodecs.imread(sourceim,Imgcodecs.CV_LOAD_IMAGE_GRAYSCALE
);
Size sz = new Size(200, 200);
Mat resizeimage = new Mat();
Imgproc.resize(img, resizeimage, sz);
Mat sourceimage = resizeimage;
Mat resizeimage2 = new Mat();
Imgproc.resize(temp, resizeimage2, sz);
Mat templateimage = resizeimage2;
int result_cols = sourceimage.cols() - templateimage.cols() + 1;
int result_rows = sourceimage.rows() - templateimage.rows() + 1;
Mat result = new Mat(result_rows, result_cols, CvType.CV_32FC1);
Imgproc.matchTemplate(sourceimage,templateimage, result, match_method);
//Core.normalize(result, result, 0, 1, Core.NORM_MINMAX, -1, new Mat());
Imgproc.threshold(result, result,0.1,1,Imgproc.THRESH_TOZERO);
Point matchLoc,maxLoc,minLoc;
Core.MinMaxLocResult mmr;
boolean iterate = true;
double minlocvalue,maxlocvalue,minminvalue,maxmaxvalue;
while(true){
mmr = Core.minMaxLoc(result);
if (match_method == Imgproc.TM_SQDIFF || match_method == Imgproc.TM_SQDIFF_NORMED) {
matchLoc = mmr.minLoc;
minminvalue = mmr.minVal; // test
} else {
matchLoc = mmr.maxLoc;
maxmaxvalue = mmr.minVal; // test
}
Log.d(TAG, "mmr.maxVal : "+mmr.maxVal);
if(mmr.maxVal >=0.2)
{
Log.d(TAG, "imagemathed..");
Imgproc.rectangle(sourceimage, matchLoc, new Point(matchLoc.x + templateimage.cols(),
matchLoc.y + templateimage.rows()), new Scalar(0, 255, 0));
Imgcodecs.imwrite(outFile, img);
Mat image = Imgcodecs.imread(outFile);
try {
Bitmap bm = Bitmap.createBitmap(image.cols(), image.rows(), Bitmap.Config.RGB_565);
Utils.matToBitmap(image, bm);
System.out.println("MinVal "+bm);
}catch(Exception e){
e.printStackTrace();
}
return true;
}else {
Log.d(TAG, "image not mathced..");
return false;
}
}
But every time I'M not getting the proper output, fault images are coming in the output.Please help me out, AM I following right approach, If not can some one suggest me which approach i have to follow.

Android Paper Detection using OpenCV

I am trying to implement Paper detection through OpenCV. I am able to understand the concept of how can I get it,
Input-> Canny-> Blur-> Find Conture-> Search (closed)Quadrilateral-> Draw Conture
but still, I am new to OpenCV programming. So having issues in implementing it. I was able to find help through this answer
Android OpenCV Paper Sheet detection
but it's drawing contour on every possible lining. Here is the code I am trying to implement.
public Mat onCameraFrame(CvCameraViewFrame inputFrame) {
mRgba = inputFrame.rgba();
Imgproc.drawContours(mRgba,findContours(mRgba), 0, new Scalar(0 , 255, 0), 5);
return mRgba;
}
public static class Quadrilateral {
public MatOfPoint contour;
public Point[] points;
public Quadrilateral(MatOfPoint contour, Point[] points) {
this.contour = contour;
this.points = points;
}
}
public static Quadrilateral findDocument( Mat inputRgba ) {
ArrayList<MatOfPoint> contours = findContours(inputRgba);
Quadrilateral quad = getQuadrilateral(contours);
return quad;
}
private static ArrayList<MatOfPoint> findContours(Mat src) {
double ratio = src.size().height / 500;
int height = Double.valueOf(src.size().height / ratio).intValue();
int width = Double.valueOf(src.size().width / ratio).intValue();
Size size = new Size(width,height);
Mat resizedImage = new Mat(size, CvType.CV_8UC4);
Mat grayImage = new Mat(size, CvType.CV_8UC4);
Mat cannedImage = new Mat(size, CvType.CV_8UC1);
Imgproc.resize(src,resizedImage,size);
Imgproc.cvtColor(resizedImage, grayImage, Imgproc.COLOR_RGBA2GRAY, 4);
Imgproc.GaussianBlur(grayImage, grayImage, new Size(5, 5), 0);
Imgproc.Canny(grayImage, cannedImage, 75, 200);
ArrayList<MatOfPoint> contours = new ArrayList<MatOfPoint>();
Mat hierarchy = new Mat();
Imgproc.findContours(cannedImage, contours, hierarchy, Imgproc.RETR_LIST, Imgproc.CHAIN_APPROX_SIMPLE);
hierarchy.release();
Collections.sort(contours, new Comparator<MatOfPoint>() {
#Override
public int compare(MatOfPoint lhs, MatOfPoint rhs) {
return Double.valueOf(Imgproc.contourArea(rhs)).compareTo(Imgproc.contourArea(lhs));
}
});
resizedImage.release();
grayImage.release();
cannedImage.release();
return contours;
}
private static Quadrilateral getQuadrilateral(ArrayList<MatOfPoint> contours) {
for ( MatOfPoint c: contours ) {
MatOfPoint2f c2f = new MatOfPoint2f(c.toArray());
double peri = Imgproc.arcLength(c2f, true);
MatOfPoint2f approx = new MatOfPoint2f();
Imgproc.approxPolyDP(c2f, approx, 0.02 * peri, true);
Point[] points = approx.toArray();
// select biggest 4 angles polygon
if (points.length == 4) {
Point[] foundPoints = sortPoints(points);
return new Quadrilateral(c, foundPoints);
}
}
return null;
}
private static Point[] sortPoints(Point[] src) {
ArrayList<Point> srcPoints = new ArrayList<>(Arrays.asList(src));
Point[] result = { null , null , null , null };
Comparator<Point> sumComparator = new Comparator<Point>() {
#Override
public int compare(Point lhs, Point rhs) {
return Double.valueOf(lhs.y + lhs.x).compareTo(rhs.y + rhs.x);
}
};
Comparator<Point> diffComparator = new Comparator<Point>() {
#Override
public int compare(Point lhs, Point rhs) {
return Double.valueOf(lhs.y - lhs.x).compareTo(rhs.y - rhs.x);
}
};
// top-left corner = minimal sum
result[0] = Collections.min(srcPoints, sumComparator);
// bottom-right corner = maximal sum
result[2] = Collections.max(srcPoints, sumComparator);
// top-right corner = minimal diference
result[1] = Collections.min(srcPoints, diffComparator);
// bottom-left corner = maximal diference
result[3] = Collections.max(srcPoints, diffComparator);
return result;
}
The answer suggests that I should use Quadrilateral Object and call it with Imgproc.drawContours(), but this function takes in ArrayList as argument where as Quadrilateral object contains MatofPoint and Point[]. Can someone help me through this..I am using OpenCV(3.3) and Android (1.5.1)?
Here is the sample what it should look like

Load Image in Mat and Display after DFT process

I got a problem loading image (in list/on click) in Mat on Android, and processing with OpenCV DFT function then return result.
This is my src
MainActivity.java
public class MainActivity extends Activity {
static final String CAMERA_PIC_DIR = "/DCIM/Camera/";
ImageView iv;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
iv = (ImageView) findViewById(R.id.my_image);
String ImageDir = Environment.getExternalStorageDirectory()
.getAbsolutePath() + CAMERA_PIC_DIR;
Intent i = new Intent(this, ListFile.class);
i.putExtra( "directory", ImageDir);
startActivityForResult(i,0);
}
#Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if(requestCode == 0 && resultCode==RESULT_OK) {
String tmp = data.getExtras().getString("clickedFile");
//Bitmap ImageToChange= BitmapFactory.decodeFile(tmp);
//Bitmap bm = Bitmap.createScaledBitmap(ImageToChange, 480, 320, false);
Mat mRgba = new Mat();
mRgba = Highgui.imread(tmp);
getDFT(mRgba);
//iv.setImageBitmap(bm);
If i uncomment 2 Line of Bitmap and iv.set , image successfully load and display list image after click.
and this is getDFT method, still on MainActivity.java
private Mat getDFT(Mat singleChannel) {
singleChannel.convertTo(singleChannel, CvType.CV_64FC1);
int m = Core.getOptimalDFTSize(singleChannel.rows());
int n = Core.getOptimalDFTSize(singleChannel.cols()); // on the border
// add zero
// values
// Imgproc.copyMakeBorder(image1,
// padded, 0, m -
// image1.rows(), 0, n
Mat padded = new Mat(new Size(n, m), CvType.CV_64FC1); // expand input
// image to
// optimal size
Imgproc.copyMakeBorder(singleChannel, padded, 0, m - singleChannel.rows(), 0,
n - singleChannel.cols(), Imgproc.BORDER_CONSTANT);
List<Mat> planes = new ArrayList<Mat>();
planes.add(padded);
planes.add(Mat.zeros(padded.rows(), padded.cols(), CvType.CV_64FC1));
Mat complexI = Mat.zeros(padded.rows(), padded.cols(), CvType.CV_64FC2);
Mat complexI2 = Mat
.zeros(padded.rows(), padded.cols(), CvType.CV_64FC2);
Core.merge(planes, complexI); // Add to the expanded another plane with
// zeros
Core.dft(complexI, complexI2); // this way the result may fit in the
// source matrix
// compute the magnitude and switch to logarithmic scale
// => log(1 + sqrt(Re(DFT(I))^2 + Im(DFT(I))^2))
Core.split(complexI2, planes); // planes[0] = Re(DFT(I), planes[1] =
// Im(DFT(I))
Mat mag = new Mat(planes.get(0).size(), planes.get(0).type());
Core.magnitude(planes.get(0), planes.get(1), mag);// planes[0]
// =
// magnitude
Mat magI = mag;
Mat magI2 = new Mat(magI.size(), magI.type());
Mat magI3 = new Mat(magI.size(), magI.type());
Mat magI4 = new Mat(magI.size(), magI.type());
Mat magI5 = new Mat(magI.size(), magI.type());
Core.add(magI, Mat.ones(padded.rows(), padded.cols(), CvType.CV_64FC1),
magI2); // switch to logarithmic scale
Core.log(magI2, magI3);
Mat crop = new Mat(magI3, new Rect(0, 0, magI3.cols() & -2,
magI3.rows() & -2));
magI4 = crop.clone();
// rearrange the quadrants of Fourier image so that the origin is at the
// image center
int cx = magI4.cols() / 2;
int cy = magI4.rows() / 2;
Rect q0Rect = new Rect(0, 0, cx, cy);
Rect q1Rect = new Rect(cx, 0, cx, cy);
Rect q2Rect = new Rect(0, cy, cx, cy);
Rect q3Rect = new Rect(cx, cy, cx, cy);
Mat q0 = new Mat(magI4, q0Rect); // Top-Left - Create a ROI per quadrant
Mat q1 = new Mat(magI4, q1Rect); // Top-Right
Mat q2 = new Mat(magI4, q2Rect); // Bottom-Left
Mat q3 = new Mat(magI4, q3Rect); // Bottom-Right
Mat tmp = new Mat(); // swap quadrants (Top-Left with Bottom-Right)
q0.copyTo(tmp);
q3.copyTo(q0);
tmp.copyTo(q3);
q1.copyTo(tmp); // swap quadrant (Top-Right with Bottom-Left)
q2.copyTo(q1);
tmp.copyTo(q2);
Core.normalize(magI4, magI5, 0, 255, Core.NORM_MINMAX);
Mat realResult = new Mat(magI5.size(), CvType.CV_8UC1);
magI5.convertTo(realResult, CvType.CV_8UC1);
return realResult;
}
and This is my ListFile.java
public class ListFile extends ListActivity {
private List<String> directoryEntries = new ArrayList<String>();
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Intent i = getIntent();
File directory = new File(i.getStringExtra("directory"));
if (directory.isDirectory()){
File[] files = directory.listFiles();
//sort in descending date order
Arrays.sort(files, new Comparator<File>(){
public int compare(File f1, File f2) {
return -Long.valueOf(f1.lastModified())
.compareTo(f2.lastModified());
}
});
//fill list with files
this.directoryEntries.clear();
for (File file : files){
this.directoryEntries.add(file.getPath());
}
ArrayAdapter<String> directoryList
= new ArrayAdapter<String>(this,
R.layout.file_row, this.directoryEntries);
//alphabetize entries
//directoryList.sort(null);
this.setListAdapter(directoryList);
}
}
#Override
protected void onListItemClick(ListView l, View v, int pos, long id) {
File clickedFile = new File(this.directoryEntries.get(pos));
Intent i = getIntent();
i.putExtra("clickedFile", clickedFile.toString());
setResult(RESULT_OK, i);
finish();
}
}
Android Successfully running, but after I click one of my choice image, android stopped working,
This is the Logcat ouput
W/dalvikvm(14245): No implementation found for native Lorg/opencv/core/Mat;.n_Mat:()J
D/AndroidRuntime(14245): Shutting down VM
W/dalvikvm(14245): threadid=1: thread exiting with uncaught exception (group=0x40cbb9c0)
E/AndroidRuntime(14245): FATAL EXCEPTION: main
E/AndroidRuntime(14245): java.lang.UnsatisfiedLinkError: Native method not found: org.opencv.core.Mat.n_Mat:()J
Link Reference:
android dft got hang
Convert Opencv DFT

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