Why my image quality after masking x get worse?
public void doMaskX() {
int[][] maskX = { { -1, -2, -1 }, { 0, 0, 0 }, { 1, 2, 1 } };
int rgb, alpha = 0;
int[][] square = new int[3][3];
for (int y = 0; y < width - 3; y++) {
for (int x = 0; x < height - 3; x++) {
int sum = 0;
for (int i = 0; i < 3; i++) {
for (int j = 0; j < 3; j++) {
rgb = imgx.getRGB(y + i, x + j);
alpha = (rgb >> 24) & 0xff;
int red = (rgb >> 16) & 0xff;
int green = (rgb >> 8) & 0xff;
int blue = rgb & 0xff;
square[i][j] = (red + green + blue)/3;
sum += square[i][j] * maskX[i][j];
}
}
rgb = (alpha << 24) | (sum << 16) | (sum << 8) | sum;
imgx.setRGB(y, x, rgb);
}
}
writeImg();
}
the quality should be better of second image and why is yellow color appears?
It is important to realize that you are computing the intensity of the gradient here and that is what you are displaying. Therefore the intensity (or magnitude) is a positive number. You have to take the absolute value:
sum=Math.abs(sum);
If you take the y derivative also then you can combine:
sum=Math.sqrt(sumx*sumx+sumy*sumy);
Related
I am new to Java and want to count red pixels in a given image. I have below code so far but not sure of what condition to add to check if pixel is red. I have below code so far. Thanks in advance.
public static int countRedPixels(Picture v){
BufferedImage image = (v.getBufferedImage());
int width = image.getWidth();
int height = image.getHeight();
int redCount = 0;
int pixelCount = 0;
for (int x = 0; x < width; x++) {
for (int y = 0; y < height ; y++) {
int rgb = image.getRGB(x, y);
//get rgbs
//int alpha = (rgb >>> 24) & 0xFF;
int red = (rgb >>> 16) & 0xFF;
int green = (rgb >>> 8) & 0xFF;
int blue = (rgb >>> 0) & 0xFF;
if (red == 255 && green == 0 && blue == 0 || image.getRGB(x, y) == 0xFFFF0000) {
redCount++;
}
pixelCount++;
}
}
System.out.println("Red Pixel Count:" + redCount);
System.out.println("Pixel Count:" + pixelCount);
return redCount;
}
Not sure if I'm missing something or you're really not seeing the forest for the trees. Anyway, comment turned answer:
Given that red means (255, 0, 0), you could do:
if (image.getRGB(x, y) == 0xFFFF0000) {
++redCount;
}
Or alternatively, if you don't care about alpha:
if (red == 255 && green == 0 && blue == 0) {
++redCount;
}
I need to determinate whether the given image is blank or it has the same pixel values please find the below code. here I want to set a tolerance. I don't want to pass top, bottom, left and right 20 pixels to this logic. please help!
for (String pic : Finallist) {
BufferedImage image = ImageIO.read(new File(pic));
final byte[] pixels = ((DataBufferByte) image.getRaster().getDataBuffer()).getData();
final int width = image.getWidth();
final int height = image.getHeight();
final boolean hasAlphaChannel = image.getAlphaRaster() != null;
boolean blankImage=true;
int[][] result = new int[height][width];
if (hasAlphaChannel) {
final int pixelLength = 4;
for (int pixel = 0, row = 0, col = 0; pixel < pixels.length; pixel += pixelLength) {
int argb = 0;
argb += (((int) pixels[pixel] & 0xff) << 24); // alpha
argb += ((int) pixels[pixel + 1] & 0xff); // blue
argb += (((int) pixels[pixel + 2] & 0xff) << 8); // green
argb += (((int) pixels[pixel + 3] & 0xff) << 16); // red
result[row][col] = argb;
if(result[row][col]!=result[0][0]) {
blankImage=false;
}
col++;
if (col == width) {
col = 0;
row++;
}
}
} else {
final int pixelLength = 3;
for (int pixel = 0, row = 0, col = 0; pixel < pixels.length; pixel += pixelLength) {
int argb = 0;
argb += -16777216; // 255 alpha
argb += ((int) pixels[pixel] & 0xff); // blue
argb += (((int) pixels[pixel + 1] & 0xff) << 8); // green
argb += (((int) pixels[pixel + 2] & 0xff) << 16); // red
result[row][col] = argb;
if(result[row][col]!=result[0][0]) {
blankImage=false;
}
col++;
if (col == width) {
col = 0;
row++;
}
}
}
if(blankImage==true) {
try {
System.out.println("Blank image found and its deleted");
File f = new File(pic);
f.delete();
} catch(Exception e) {
System.out.println("Exception"+e);
}
}else {
FinalListWithOutBlank.add(pic);
}
}
I want every thing on the air!! so that my code performance will not be in the pain.. I just want to skip those pixel to reach out into this logic..
Copy the desired area of interest into another image with
BufferedImage imageForEvaluation = image.getSubimage(x, y, width, height);
and use this image for your logic.
I'm trying to access each pixel, manipulate it then save it back to the system. But the resulting image is always flipped and rotated, why is this?
Here is my code for input:
BufferedImage input_image=ImageIO.read(new File("F:\\sophie4.png"));
int result[][] = convertTo2DWithoutUsingGetRGB(input_image);
private static int[][] convertTo2DWithoutUsingGetRGB(BufferedImage image) {
final byte[] pixels = ((DataBufferByte) image.getRaster().getDataBuffer()).getData();
final int width = image.getWidth();
final int height = image.getHeight();
final boolean hasAlphaChannel = image.getAlphaRaster() != null;
int[][] result = new int[height][width];
if (hasAlphaChannel) {
final int pixelLength = 4;
for (int pixel = 0, row = 0, col = 0; pixel < pixels.length; pixel += pixelLength) {
int argb = 0;
argb += (((int) pixels[pixel] & 0xff) << 24); // alpha
argb += ((int) pixels[pixel + 1] & 0xff); // blue
argb += (((int) pixels[pixel + 2] & 0xff) << 8); // green
argb += (((int) pixels[pixel + 3] & 0xff) << 16); // red
result[row][col] = argb;
col++;
if (col == width) {
col = 0;
row++;
}
}
} else {
final int pixelLength = 3;
for (int pixel = 0, row = 0, col = 0; pixel < pixels.length; pixel += pixelLength) {
int argb = 0;
argb += -16777216; // 255 alpha
argb += ((int) pixels[pixel] & 0xff); // blue
argb += (((int) pixels[pixel + 1] & 0xff) << 8); // green
argb += (((int) pixels[pixel + 2] & 0xff) << 16); // red
result[row][col] = argb;
col++;
if (col == width) {
col = 0;
row++;
}
}
}
return result;
}
That works, i get the pixels, but even without processing the pixels, if i output the image, its always flipped.. Here is my output code:
BufferedImage image = new BufferedImage(result.length, result[0].length, BufferedImage.TYPE_INT_RGB);
for (int row = 0; row < result.length; row ++) {
for (int col = 0; col < result[row].length; col++) {
image.setRGB(row, col, result[row][col]);
}
}
File ImageFile = new File("path");
try {
ImageIO.write(image, "png", ImageFile);
} catch (IOException e) {
e.printStackTrace();
}
You can see the input and output image below
You're getting confused (or at least I am), because you're resulting array is height by width (not width x height which makes more sense to me), so, instead of...
BufferedImage image = new BufferedImage(result.length, result[0].length, BufferedImage.TYPE_INT_RGB);
it should be...
BufferedImage image = new BufferedImage(result[0].length, result.length, BufferedImage.TYPE_INT_RGB);
and
image.setRGB(row, col, result[row][col]);
should be
image.setRGB(col, row, result[row][col]); // See why that's consfusing
I need to toggle on/off RGB channels of an image, but I am stuck and my code is buggy.
Can you help me figure out how to do this the right way? This is my code:
The function channels is called when 1 of 3 checkboxes has changed its state and provides the arguments which are true == selected
public void channels(boolean red, boolean green, boolean blue) {
if (this.img != null) {// checks if the image is set
char r = 0xFF, g = 0xFF, b = 0xFF;
if (red == false) {
r = 0x00;
}
if (green == false) {
g = 0x00;
}
if (blue == false) {
b = 0x00;
}
BufferedImage tmp = new BufferedImage(
img.getWidth(),
img.getHeight(),
BufferedImage.TYPE_INT_RGB);
for (int i = 0; i < img.getWidth(); i++) {
for (int j = 0; j < img.getHeight(); j++) {
int rgb = img.getRGB(i, j);
int red = (rgb >> 16) & r;
int green = (rgb >> 8) & g;
int blue = (rgb >> 0) & b;
int gbr = (red << 16) | (green << 8) | blue;// EDITED
tmp.setRGB(i, j, gbr);
}
}
img = tmp;
repaint();
} else {
//show error
}
}
Thank you for your help!
How about this optimized version, with a lot less bit shifting?
public void channels(boolean showRed, boolean showGreen, boolean showBlue) {
if (this.origImg!= null) {// checks if the image is set
int channelMask = 0xff << 24 | (showRed ? 0xff : 0) << 16 | (showGreen ? 0xff : 0) << 8 | (showBlue ? 0xff : 0);
BufferedImage tmp = new BufferedImage(origImg.getWidth(), origImg.getHeight(), BufferedImage.TYPE_INT_RGB);
for (int i = 0; i < origImg.getWidth(); i++) {
for (int j = 0; j < origImg.getHeight(); j++) {
int rgb = origImg.getRGB(i, j);
tmp.setRGB(i, j, rgb & channelMask);
}
}
img = tmp;
repaint();
} else {
//show error
}
}
A faster approach yet, would probably be to use a channeled Raster, or at least a Raster configuration that allows band sub-sampling (see Raster.createChild(...) method, especially the last parameter).
LookupOp, as mentioned by #trashgod is also a good idea, and probably faster than the getRGB()/setRGB() approach.
It looks like you're shifting in the bits wrong. Shouldn't it be: int gbr = (red << 16) | (green << 8) | blue;? You basically want to shift back in the same order as how you shifted out to begin with.
Also, once you have cleared the corresponding colour, there's no way for you to get it back. You'll need to store a copy of the original image somewhere. When it's time to turn the channel back on, simply copy the original pixel from the original image back.
Assuming that you have the original image stored somewhere as origImg, I would modify your for loop so that if the channel is toggled on, copy from the original image.
for (int i = 0; i < img.getWidth(); i++) {
for (int j = 0; j < img.getHeight(); j++) {
int rgb = img.getRGB(i, j);
int origRGB = origImg.getRGB(i, j);
int redPixel = red ? (origRGB >> 16) & r : (rgb >> 16) & r;
int greenPixel = green ? (origRGB >> 8) & g : (rgb >> 8) & g;
int bluePixel = blue ? origRGB & b : rgb & b;
int gbr = (redPixel << 16) | (greenPixel << 8) | bluePixel;
tmp.setRGB(i, j, gbr);
}
}
I have a BufferedImage which represents a 2048X2048 pixels tiff image. I wish to retrieve such array (int [2048][2048] from the BufferedImage. How should I proceed?
arr = new int[2048][2048];
for(int i = 0; i < 2048; i++)
for(int j = 0; j < 2048; j++)
arr[i][j] = image.getRGB(i, j);
Since you can get the RGB value of each pixel from the image data structure itself, it might be a benefit to NOT copy everything over to a 2d array.
This method will return the red, green and blue values directly for each pixel, and if there is an alpha channel it will add the alpha value. Using this method is harder in terms of calculating indices, but is much faster than the first approach.
private static int[][] convertTo2DWithoutUsingGetRGB(BufferedImage image) {
final byte[] pixels = ((DataBufferByte) image.getRaster().getDataBuffer()).getData();
final int width = image.getWidth();
final int height = image.getHeight();
final boolean hasAlphaChannel = image.getAlphaRaster() != null;
int[][] result = new int[height][width];
if (hasAlphaChannel) {
final int pixelLength = 4;
for (int pixel = 0, row = 0, col = 0; pixel < pixels.length; pixel += pixelLength) {
int argb = 0;
argb += (((int) pixels[pixel] & 0xff) << 24); // alpha
argb += ((int) pixels[pixel + 1] & 0xff); // blue
argb += (((int) pixels[pixel + 2] & 0xff) << 8); // green
argb += (((int) pixels[pixel + 3] & 0xff) << 16); // red
result[row][col] = argb;
col++;
if (col == width) {
col = 0;
row++;
}
}
} else {
final int pixelLength = 3;
for (int pixel = 0, row = 0, col = 0; pixel < pixels.length; pixel += pixelLength) {
int argb = 0;
argb += -16777216; // 255 alpha
argb += ((int) pixels[pixel] & 0xff); // blue
argb += (((int) pixels[pixel + 1] & 0xff) << 8); // green
argb += (((int) pixels[pixel + 2] & 0xff) << 16); // red
result[row][col] = argb;
col++;
if (col == width) {
col = 0;
row++;
}
}
}
return result;
}