I know how to get the RGB values of individual pixels of a bitmap. How can I get the average RGB value for all of the pixels of a bitmap?
I think below code for exact answer to you.
Get the Average(Number of pixels)of Red, Green and Blue value for the given bitmap.
Bitmap bitmap = someBitmap; //assign your bitmap here
int redColors = 0;
int greenColors = 0;
int blueColors = 0;
int pixelCount = 0;
for (int y = 0; y < bitmap.getHeight(); y++)
{
for (int x = 0; x < bitmap.getWidth(); x++)
{
int c = bitmap.getPixel(x, y);
pixelCount++;
redColors += Color.red(c);
greenColors += Color.green(c);
blueColors += Color.blue(c);
}
}
// calculate average of bitmap r,g,b values
int red = (redColors/pixelCount);
int green = (greenColors/pixelCount);
int blue = (blueColors/pixelCount);
The answer from john sakthi does not work correctly if the Bitmap has transparency (PNGs). I modified the answer for correctly getting the red/green/blue averages while accounting for transparent pixels:
/**
* Calculate the average red, green, blue color values of a bitmap
*
* #param bitmap
* a {#link Bitmap}
* #return
*/
public static int[] getAverageColorRGB(Bitmap bitmap) {
final int width = bitmap.getWidth();
final int height = bitmap.getHeight();
int size = width * height;
int pixelColor;
int r, g, b;
r = g = b = 0;
for (int x = 0; x < width; ++x) {
for (int y = 0; y < height; ++y) {
pixelColor = bitmap.getPixel(x, y);
if (pixelColor == 0) {
size--;
continue;
}
r += Color.red(pixelColor);
g += Color.green(pixelColor);
b += Color.blue(pixelColor);
}
}
r /= size;
g /= size;
b /= size;
return new int[] {
r, g, b
};
}
you can use this method for this purpose: Bitmap.createBitmap
For instance:
int[] colors = new int[yourWidth * yourHeight];
Arrays.fill(colors, Color.Black);
Bitmap bitamp = Bitamp.createBitmap(colors, yourWidth, yourHeight, Bitmap.Config.ARGB_8888);
Check for typo
Related
I have to write a method that:
Create a histogram
read all pixel values from grayscale images (variable width and height)
fill the histogram
How can I do it? I wrote a bit of code but I'm deadlocked.
public histogram(BufferedImage image){
WritableRaster writableRaster = image.getRaster();
int width = image.getWidth();
int height = image.getHeight();
int pixelValue;
for (int y = 0; y < height; y++) {
for (int x = 0; x < width; x++) {
pixelValue = writableRaster.setDataElements(x, y, width, height, );
}
}
}
The following code snippet should help:
Raster raster = image.getRaster();
int numBands = raster.getSampleModel().getNumBands();
int width = image.getWidth();
int height = image.getHeight();
for (int y = 0; y < height; y++) {
for (int x = 0; x < width; x++) {
int[] pixelValue = new int[numBands];
raster.getPixel(x, y, pixelValue);
}
}
If you really have a grayscale image without alpha, the SampleModel will contain only one band. In this case the pixelValue array will contain your desired int value. You only have to add an histogram array of 256 int values and increase the value at the index of your pixel value.
I want to put a tensorflow model on Anroid.
I recently noticed that the results of running the same data in Python and Android, respectively, are inconsistent.
After several trial and error, I found that the input data I entered when I ran the model on Android was wrong.
It was just a java.lang.IllegalArgumentException error, and I think I put the data correctly, but I have no idea what went wrong.
I used images that were transformed into image resizing and gray scale as learning data. in Python
I did the same preprocessing on Android.
My image type is .jpg
I attached my source.
Source related to image preprocessing
btntrans.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
try {
image_bitmap = resizeBitmapImage(image_bitmap, 28);
image_bitmap = RGB2GRAY(image_bitmap);
image.setImageBitmap(image_bitmap);
byte[] byteArrayRes = bitmapToByteArray(image_bitmap);
float[] inputArray = bytetofloat(byteArrayRes);
activityPrediction(inputArray);
}
catch(Exception e){
}
}
});
Everything happens when I click the button
resizeBitmapImage method
public Bitmap resizeBitmapImage(Bitmap source, int maxResolution)
{
int width = source.getWidth();
int height = source.getHeight();
int newWidth = width;
int newHeight = height;
float rate = 0.0f;
if(width > height)
{
if(maxResolution < width)
{
rate = maxResolution / (float) width;
newHeight = (int) (height * rate);
newWidth = maxResolution;
}
}
else
{
if(maxResolution < height)
{
rate = maxResolution / (float) height;
newWidth = (int) (width * rate);
newHeight = maxResolution;
}
}
return Bitmap.createScaledBitmap(source, newWidth, newHeight, true);
}
RGB2GRAY method
public Bitmap RGB2GRAY(Bitmap image){
int width = image.getWidth();
int height = image.getHeight();
Bitmap bmOut;
bmOut = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_4444);
for(int x = 0; x < width; x++){
for(int y = 0 ; y < height; y++){
int pixel = image.getPixel(x, y);
int A = Color.alpha(pixel);
int R = Color.red(pixel);
int G = Color.green(pixel);
int B = Color.blue(pixel);
R = G = B = (int)(0.299 * R + 0.587 * G + 0.114 * B);
bmOut.setPixel(x, y, Color.argb(A, R, G, B));
}
}
return bmOut;
}
bitmap to byte array method
private byte[] bitmapToByteArray(Bitmap bitmap){
ByteArrayOutputStream stream = new ByteArrayOutputStream();
bitmap.compress(Bitmap.CompressFormat.JPEG, 100, stream);
return stream.toByteArray();
}
bytetofloat method
public float[] bytetofloat(byte[] array){
int[] returnArr = new int[array.length/4];
float[] returnArr1 = new float[array.length/4];
for(int i = 0 ; i < returnArr.length; i++){
//array[i] = 0;
returnArr[i] = array[i*4] & 0xFF;
if(returnArr[i] < 0 || returnArr[i]>255)
Log.d("ARRAY", returnArr[i]+" ");
returnArr1[i] = (float)returnArr[i];
}
return returnArr1;
}
When I run it with the above source, I get this error exactly.
java.lang.IllegalArgumentException: buffer with 308 elements is not
compatible with a Tensor with shape [1, 28, 28]
28 * 28 is Input image size
Before image resizing, it had an average width of 20 and a height of 36.
The strange thing is that the number 308 is changed to 306, 307 and fixed.
What can i do?
Here is my method for converting Java BufferedImage to Tensor object:
private static Tensor<?> convertImageToArray(BufferedImage bf) {
int width = bf.getWidth();
int height = bf.getHeight();
float[][][][] rgbArray = new float[1][height][width][3];
for (int i = 0; i < height; i++) {
for (int j = 0; j < width; j++) {
bf.getRaster().getPixel(i, j, rgbArray[0][i][j]);
}
}
return Tensor.create(rgbArray);
}
Your problem is probably in missed channels of your image. Float array length must be equal to
height * width * channels
of the image.
I'm creating a method that takes two parameters with 2 indexes a start and an end that takes a location of the picture being edited and turn those pixels to a different color. Using a while loop to index start and end.
The problem I'm having is I'm only a getting a really small portion to change color:
Don't mind some of the code that is commented out. I was trying a bunch of different things.
public void negative(int start, int end)
{
Pixel[] pixelArray = this.getPixels(); //pixelarray index
Pixel pixel = null;
// int height = this.getHeight();
//int paintPoint = height / 2;
//int width = this.getWidth();
int i = 0;
int red, green, blue = 0;
// int x = 0;
Pixel topPixel = null;
Pixel bottomPixel = null;
//int startY;
//int startX;
int y = start;
int x = end;
//int count;
while( y < this.getHeight())
{
y++;
while (x < this.getWidth()) //loops through index
{
pixel = this.getPixel(x,y);
red = pixel.getRed();
green = pixel.getGreen();//collects color green
blue = pixel.getBlue();//collects color blue
Color negColor = new Color( 255 - red, 255 - green, 255 - blue);//sets new values of pixels
pixel.setColor(negColor);
x++;
//count = count + 1;
i++;//indexes continuing
}
}
}
A picture is 2D yet you are treating it as 1D (notice after once through your inner x loop it never is reset to its min value). If you wish to color an arbitrary rectangle within a given photo the parms should include two points : minx, miny and maxx maxy then your pair of 2D loops visits each point in that region line by line.
// do sanity checks on your parms
if (this.getWidth() < maxx) {
maxx = this.getWidth();
}
if (this.getHeight() < maxy) {
maxy = this.getHeight();
}
if (minx < 0) {
minx = 0;
}
if (miny < 0) {
miny = 0;
}
for (y = mixy; y < maxy; y++) {
for (x = mixx; x < maxx; x++) {
// now your have valid x and y values
}
}
I am writing a java code that divides an image into chunks and rotate to some degree and combine the chunks to become one final image. Then use same code to divide the image into chunks and rotate opposite. I expect to get the same image as the original but I get an image with black line separated between them. For example an image is divided into 8 rows and 8 columns and conduct rotation. I have googled it and come up with the following code:
public static BufferedImage Didvide( BufferedImage image , int Bz ,double angle ){
int rows = Bz;
int cols = Bz;
int chunks = rows * cols;
int chunkWidth = image.getWidth() / cols;
int chunkHeight = image.getHeight() / rows;
int count = 0;
BufferedImage imgs[] = new BufferedImage[chunks];
for (int x = 0; x < rows; x++) {
for (int y = 0; y < cols; y++) {
imgs[count] = new BufferedImage(chunkWidth, chunkHeight,
image.getType());
// draws image chunk
Graphics2D gr = imgs[count++].createGraphics();
gr.drawImage(image, 0, 0, chunkWidth, chunkHeight, chunkWidth
* y, chunkHeight * x, chunkWidth * y + chunkWidth,
chunkHeight * x + chunkHeight, null);
gr.dispose();
}
}
BufferedImage[] Rimgs = new BufferedImage[imgs.length];
for (int i = 0; i < imgs.length; i++) {
Rimgs[i] = rotate(imgs[i], angle);
}
chunkWidth = Rimgs[0].getWidth();
chunkHeight = Rimgs[0].getHeight();
// Initializing the final image
BufferedImage finalImg = new BufferedImage(chunkWidth * cols,
chunkHeight * rows, BufferedImage.TYPE_3BYTE_BGR);
int num = 0;
for (int i = 0; i < rows; i++) {
for (int j = 0; j < cols; j++) {
finalImg.createGraphics().drawImage(Rimgs[num], chunkWidth * j,
chunkHeight * i, null);
num++;
} } return finalImg; }
public static BufferedImage rotate(BufferedImage image, double angle) {
double sin = Math.abs(Math.sin(angle)), cos = Math.abs(Math.cos(angle));
int w = image.getWidth(), h = image.getHeight();
int neww = (int) Math.floor(w * cos + h * sin), newh = (int) Math
.floor(h * cos + w * sin);
GraphicsConfiguration gc = getDefaultConfiguration();
BufferedImage result = gc.createCompatibleImage(neww, newh,
Transparency.OPAQUE);
Graphics2D g = result.createGraphics();
g.translate((neww - w) / 2, (newh - h) / 2);
g.rotate(angle, w / 2, h / 2);
g.drawRenderedImage(image, null);
g.dispose();
return result;
}
The problem I face after dividing an image of baboo gray-scale 298X298 pixel into 8 col and 8 row, the resulting image has black lines separating columns. However when I divide the image into 12 or 4 it works fine. Can you please let me know where I should consider.
Seems I can not post image.
When I divide and rotate the image into 8 rows and 8 columns of an image with 298X298, I get a result of 296X296 pixel. How can I fix this. So the size of before dividing and rotating is same as after.
Thanks in advance for your help.
OK. so let's say I have this picture: http://i.stack.imgur.com/oYhJy.png
I'm trying to do a crop (which works -- I just have the wrong numbers) of the image into separate image arrays. The tile image (linked above) is 36 tiles wide and 15 tiles long. So that's 1152 pixels in width (32 tile width * 36 tiles) and 480 pixels in height (32 tile height * 15 tiles).
Here's what I have so far:
for (int xi = 0; xi < 522; xi++) {
int cropHeight = 32;
int cropWidth = 32;
int cropStartX = xi*32;
int cropStartY = 0;
if (xi % 36 == 0) {
cropStartY = xi*32;
}
BufferedImage processedImage = cropMyImage(originalImage, cropWidth, cropHeight, cropStartX, cropStartY);
tiles[xi] = processedImage;
}
What am I doing wrong? It's working technically, but it's getting the wrong tile images.
Probably clearer if you did a double loop rather than trying to use modulus.
int i = 0;
// no need to have these values inside a loop. They are constants.
int cropHeight = 32;
int cropWidth = 32;
for (int x = 0; x < 36; x++) {
for (int y = 0; y < 15; y++) {
int cropStartX = x*32;
int cropStartY = y*32;
BufferedImage processedImage = cropMyImage(originalImage, cropWidth, cropHeight, cropStartX, cropStartY);
tiles[i++] = processedImage;
}
}
Probably should be:
int cropStartX = (xi%36)*32;
int cropStartY = xi/36*32;