Android下otsu算法实现,android - Otsu histogram self implementation - Stack Overflow

I tried to make my own implementation of Otsu. I already read some source code from java and some sites that explains the formula and tried to implement it. I want to share this to ask if anyone can help me or at least tell about what can I do or improve.

I already coded get width, height and the background and foreground weight, mean, variance, and within class variance.

Note that I have not implemented how to set or find the exact threshold or even change the picture to black-white(binarize) using within class variance. If you can help me, feel welcome to. I also see some java codes that has treshhold = i or treshhold = t but I can't see how they made the image to black-white.

Here is my code:

Otsu.java

Bitmap tempImg = (Bitmap) original;

Bitmap OImg = Bitmap.createBitmap(tempImg.getWidth(), tempImg.getHeight(), tempImg.getConfig());

int width = tempImg.getWidth();

int height = tempImg.getHeight();

int A, R, G, B,colorPixel;

for (int x = 0; x < width; x++) { //original image to grayscale

for (int y = 0; y < height; y++) {

colorPixel = tempImg.getPixel(x, y);

A = Color.alpha(colorPixel);

R = Color.red(colorPixel);

G = Color.green(colorPixel);

B = Color.blue(colorPixel);

R = (R + G + B) / 3;

G = R;

B = R;

OImg.setPixel(x, y, Color.argb(A, R, G,B ));

}

}

return OImg;

}

public static Bitmap Botsu(Bitmap gImg){

Bitmap tempImg = (Bitmap) gImg;

Bitmap BWimg = Bitmap.createBitmap(tempImg.getWidth(), tempImg.getHeight(), tempImg.getConfig());

int width = tempImg.getWidth();

int height = tempImg.getHeight();

int A, R, G, B, colorPixel;

// histo-thresh

double Wcv = 0;

int[] Bx = new int[256];

int[] By = new int[256];

int[] Fx = new int[256];

int[] Fy = new int[256];

double Bw =0, Bm =0, Bv =0, Bp = 0;

double Fw =0, Fm =0, Fv =0, Fp = 0;

int c = 0, ImgPix = 0, ImgPixB = 0, ImgPixF = 0, newPixel = 0;

// pixel check for histogram

for (int x = 0; x < width; x++) {

for (int y = 0; y < height; y++) {

colorPixel = tempImg.getPixel(x, y);

A = Color.alpha(colorPixel);

R = Color.red(colorPixel);

G = Color.green(colorPixel);

B = Color.blue(colorPixel);

int gray = (int) (0.2989 * R + 0.5870 * G + 0.1140 * B);

if (gray > 128) { // white - foreground

for (int z=0; z

if (Fx[z] == gray){

c++;

}

}

if (c==1){

Fy[gray] = Fy[gray]+1; //y axis - counter for pixels for each x

}

else{

Fx[x] = gray; //x axis - 0-255

Fy[gray] = Fy[gray]+1;

}

}//By[Bx[x]]

else{ // black - background

for (int z=0; z

if (Bx[z] == gray){

c++;

}

}

if (c==1){

By[gray] = By[gray]+1; //y axis - counter for pixels for each x

}

else{

Bx[x] = gray; //x axis - 0-255

By[gray] = By[gray]+1;

}

}

}

}

for (int b=0; b

ImgPixB = ImgPixB + By[b];

}

for (int f=0; f

ImgPixF = ImgPixF + Fy[f];

}

ImgPix = ImgPixB + ImgPixF;

//bg part hist

for (int i=0; i

Bw = Bw + By[i];

}

Bw = Bw/ImgPix;

for (int i=0; i

Bp = Bp + By[i];

}

for (int i = 0; i

Bm = Bm + (Bx[i]*By[Bx[i]]);

}

Bm = Bm/Bp;

for (int i=0; i

Bv = Bv + (Math.pow((Bx[i]-Bm),2)*By[Bx[i]]); // (Bx[i]-Bm) * (Bx[i]-Bm)

}

Bv = Bv/Bp;

//fg part hist

for (int i=0; i

Fw = Fw + Fy[i];

}

Fw = Fw/ImgPix;

for (int i=0; i

Fp = Fp + Fy[i];

}

for (int i = 0; i

Fm = Fm + (Fx[i]*Fy[Fx[i]]);

}

Fm = Fm/Fp;

for (int i=0; i

Fv = Fv + (Math.pow((Fx[i]-Fm),2)*Fy[Fx[i]]); // (Bx[i]-Bm) * (Bx[i]-Bm)

}

Fv = Fv/Fp;

// within class variance

Wcv = (Bw * Bv) + (Fw * Fv);

for (int x = 0; x < width; x++) {

for (int y = 0; y < height; y++) {

colorPixel = tempImg.getPixel(x, y);

A = Color.alpha(colorPixel);

R = Color.red(colorPixel);

G = Color.green(colorPixel);

B = Color.blue(colorPixel);

//int gray = (int) (0.2989 * R + 0.5870 * G + 0.1140 * B);

int gray2 = (int) (Wcv * R + Wcv * G + Wcv * B);

if (gray2 > 128) {

gray2 = 255;

}

else if (gray2 <129){

gray2 = 0;

}

BWimg.setPixel(x, y, Color.argb(A, gray2, gray2, gray2));

}

}

return BWimg;

x[z] is for x-axis andy[gray] is for y-axis. I based this on the graph on Lab Book

x = 0-255

y = how many pixels is on a certain color shade

feel free to send more samples that can help me.

OUTPUT: (I added 2 function with 3 output that has an output. Other value will only return few black dots or just white image.)

if (gray2 > 128) {

gray2 = 255;

}

else if (gray2 < 129){

gray2 = 0;

}

if (gray2 > 64 && gray2 < 129) {

gray2 = 255;

}

else if (gray2 < 65){

gray2 = 0;

}