I'm attempting to take a picture as input, then manipulate said picture (I specifically want to make it greyscale) and then output the new image. This is a snippet of the code that I'm editing in order to do so but I'm getting stuck. Any ideas of what I can change/do next. Greatly appreciated!
public boolean recieveFrame (Image frame) {
int width = frame.width();
int height = frame.height();
for (int i = 0; i < width; i++) {
for (int j = 0; j < height; j++) {
Color c1 = frame.get(i, j);
double greyScale = (double) ((Color.red *.3) + (Color.green *.59) + (Color.blue * .11));
Color newGrey = Color.greyScale(greyScale);
frame.set(i, j, newGrey);
}
}
boolean shouldStop = displayImage(frame);
return shouldStop;
}
I'm going to try to stick as close as possible to what you already have. So, I'll assume that you are looking for how to do pixel-level processing on an Image, rather than just looking for a technique that happens to work for converting to greyscale.
The first step is that you need the image to be a BufferedImage. This is what you get by default from ImageIO, but if you have some other type of image, you can create a BufferedImage and paint the other image into it first:
BufferedImage buffer = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
Graphics2D g = buffer.createGraphics();
g.drawImage(image, 0, 0);
g.dispose()
Then, you can operate on the pixels like this:
public void makeGrey(BufferedImage image) {
for(int x = 0; x < image.getWidth(); ++x) {
for(int y = 0; y < image.getHeight(); ++y) {
Color c1 = new Color(image.getRGB(x, y));
int grey = (int)(c1.getRed() * 0.3
+ c1.getGreen() * 0.59
+ c1.getBlue() * .11
+ .5);
Color newGrey = new Color(grey, grey, grey);
image.setRGB(x, y, newGrey.getRGB());
}
}
}
Note that this code is horribly slow. A much faster option is to extract all the pixels from the BufferedImage into an int[], operate on that, and then set it back into the image. This uses the other versions of the setRGB()/getRGB() methods that you'll find in the javadoc.
Related
For an automation tool I'm working on I need to compare 2 images.
My code works perfectly when I have "normal" images, but it fails when one of the images has a transparent area.
I'm reducing the color between the images for each pixel and creating a negative image that shows the difference. For images with transparent area the negative image is whole white, I can't see any shape or other info.
How to ignore the transparent area (shown in the images as gray color)?
My code:
private static BufferedImage createDiffImage(BufferedImage img1, BufferedImage img2) {
BufferedImage result = new BufferedImage(img1.getWidth(), img1.getHeight(), img1.getType());
int color;
for(int x = 0; x < img1.getWidth(); x++)
for(int y = 0; y < img1.getHeight(); y++) {
color = Math.abs(img2.getRGB(x, y) - img1.getRGB(x, y));
result.setRGB(x, y, color);
}
return result;
}
I found the solution:
private static BufferedImage createDiffImage(BufferedImage img1, BufferedImage img2) {
BufferedImage result = new BufferedImage(img1.getWidth(), img1.getHeight(), img1.getType());
for(int x = 0; x < img1.getWidth(); x++)
for(int y = 0; y < img1.getHeight(); y++) {
Color c1 = new Color(img1.getRGB(x,y));
Color c2 = new Color(img2.getRGB(x,y));
int alpha = 255;
int red = Math.abs(c1.getRed() - c2.getRed());
int green = Math.abs(c1.getGreen() - c2.getGreen());
int blue = Math.abs(c1.getBlue() - c2.getBlue());
Color negativeColor = new Color(red,green,blue, alpha);
result.setRGB(x, y, negativeColor.getRGB());
}
return result;
}
I'm using the following to add overlay to a video; but it doesn't perform well because it requires to process every pixels (which is A LOT of work if you have full-HD at 50 frames/sec!)
private static byte[] convert(BufferedImage image, int opacity)
{
int imgWidth = image.getWidth();
int imgHeight = image.getHeight();
byte[] buffer = new byte[imgWidth * imgHeight * 4]
int imgLoc = 0;
for(int y=0; y < imgHeight; y++)
{
for(int x=0; x < imgWidth; x++)
{
int argb = image.getRGB(x, y);
imgBuffer[(imgLoc*4)+0] = (byte)((argb>>0)&0x0FF);
imgBuffer[(imgLoc*4)+1] = (byte)((argb>>8)&0x0FF);
imgBuffer[(imgLoc*4)+2] = (byte)((argb>>16)&0x0FF);
int alpha = ((argb>>24)&0x0FF);
if (opacity < 100)
alpha = (alpha*opacity)/100;
imgBuffer[(imgLoc*4)+3] = (byte)alpha;
imgLoc++;
}
}
How can I re-write this code to perform better? I've tried many different things, e.g.:
image.getRGB(0, 0, image.getWidth(), image.getHeight(), null, 0, image.getWidth());
((DataBufferByte) image.getData().getDataBuffer()).getData()
But none of these seem to work; the overlay doesn't show up, while the slower method at least shows the overlay.
PS: I know the ARGB is converted to ABGR in the function above; I'll fix that later. The overlay should still show, albeit in different colors
Hi I am in need of some help. I need to write a convolution method from scratch that takes in the following inputs: int[][] and BufferedImage inputImage. I can assume that the kernel has size 3x3.
My approach is to do the follow:
convolve inner pixels
convolve corner pixels
convolve outer pixels
In the program that I will post below I believe I convolve the inner pixels but I am a bit lost at how to convolve the corner and outer pixels. I am aware that corner pixels are at (0,0), (width-1,0), (0, height-1) and (width-1,height-1). I think I know to how approach the problem but not sure how to execute that in writing though. Please to aware that I am very new to programming :/ Any assistance will be very helpful to me.
import java.awt.*;
import java.awt.image.BufferedImage;
import com.programwithjava.basic.DrawingKit;
import java.util.Scanner;
public class Problem28 {
// maximum value of a sample
private static final int MAX_VALUE = 255;
//minimum value of a sample
private static final int MIN_VALUE = 0;
public BufferedImage convolve(int[][] kernel, BufferedImage inputImage) {
}
public BufferedImage convolveInner(double center, BufferedImage inputImage) {
int width = inputImage.getWidth();
int height = inputImage.getHeight();
BufferedImage inputImage1 = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
//inner pixels
for (int x = 1; x < width - 1; x++) {
for (int y = 1; y < height - 1; y ++) {
//get pixels at x, y
int colorValue = inputImage.getRGB(x, y);
Color pixelColor = new Color(colorValue);
int red = pixelColor.getRed() ;
int green = pixelColor.getGreen() ;
int blue = pixelColor.getBlue();
int innerred = (int) center*red;
int innergreen = (int) center*green;
int innerblue = (int) center*blue;
Color newPixelColor = new Color(innerred, innergreen, innerblue);
int newRgbvalue = newPixelColor.getRGB();
inputImage1.setRGB(x, y, newRgbvalue);
}
}
return inputImage1;
}
public BufferedImage convolveEdge(double edge, BufferedImage inputImage) {
int width = inputImage.getWidth();
int height = inputImage.getHeight();
BufferedImage inputImage2 = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
//inner pixels
for (int x = 0; x < width - 1; x++) {
for (int y = 0; y < height - 1; y ++) {
//get pixels at x, y
int colorValue = inputImage.getRGB(x, y);
Color pixelColor = new Color(colorValue);
int red = pixelColor.getRed() ;
int green = pixelColor.getGreen() ;
int blue = pixelColor.getBlue();
int innerred = (int) edge*red;
int innergreen = (int) edge*green;
int innerblue = (int) edge*blue;
Color newPixelColor = new Color(innerred, innergreen, innerblue);
int newRgbvalue = newPixelColor.getRGB();
inputImage2.setRGB(x, y, newRgbvalue);
}
}
return inputImage2;
}
public BufferedImage convolveCorner(double corner, BufferedImage inputImage) {
int width = inputImage.getWidth();
int height = inputImage.getHeight();
BufferedImage inputImage3 = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
//inner pixels
for (int x = 0; x < width - 1; x++) {
for (int y = 0; y < height - 1; y ++) {
//get pixels at x, y
int colorValue = inputImage.getRGB(x, y);
Color pixelColor = new Color(colorValue);
int red = pixelColor.getRed() ;
int green = pixelColor.getGreen() ;
int blue = pixelColor.getBlue();
int innerred = (int) corner*red;
int innergreen = (int) corner*green;
int innerblue = (int) corner*blue;
Color newPixelColor = new Color(innerred, innergreen, innerblue);
int newRgbvalue = newPixelColor.getRGB();
inputImage3.setRGB(x, y, newRgbvalue);
}
}
return inputImage3;
}
public static void main(String[] args) {
DrawingKit dk = new DrawingKit("Compositor", 1000, 1000);
BufferedImage p1 = dk.loadPicture("image/pattern1.jpg");
Problem28 c = new Problem28();
BufferedImage p5 = c.convolve();
dk.drawPicture(p5, 0, 100);
}
}
I changed the code a bit but the output comes out as black. What did I do wrong:
import java.awt.*;
import java.awt.image.BufferedImage;
import com.programwithjava.basic.DrawingKit;
import java.util.Scanner;
public class Problem28 {
// maximum value of a sample
private static final int MAX_VALUE = 255;
//minimum value of a sample
private static final int MIN_VALUE = 0;
public BufferedImage convolve(int[][] kernel, BufferedImage inputImage) {
int width = inputImage.getWidth();
int height = inputImage.getHeight();
BufferedImage inputImage1 = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
//for every pixel
for (int x = 0; x < width; x ++) {
for (int y = 0; y < height; y ++) {
int colorValue = inputImage.getRGB(x,y);
Color pixelColor = new Color(colorValue);
int red = pixelColor.getRed();
int green = pixelColor.getGreen();
int blue = pixelColor.getBlue();
double gray = 0;
//multiply every value of kernel with corresponding image pixel
for (int i = 0; i < 3; i ++) {
for (int j = 0; j < 3; j ++) {
int imageX = (x - 3/2 + i + width) % width;
int imageY = (x -3/2 + j + height) % height;
int RGB = inputImage.getRGB(imageX, imageY);
int GRAY = (RGB) & 0xff;
gray += (GRAY*kernel[i][j]);
}
}
int out;
out = (int) Math.min(Math.max(gray * 1, 0), 255);
inputImage1.setRGB(x, y, new Color(out,out,out).getRGB());
}
}
return inputImage1;
}
public static void main(String[] args) {
int[][] newArray = {{1/9, 1/9, 1/9}, {1/9, 1/9, 1/9}, {1/9, 1/9, 1/9}};
DrawingKit dk = new DrawingKit("Problem28", 1000, 1000);
BufferedImage p1 = dk.loadPicture("image/pattern1.jpg");
Problem28 c = new Problem28();
BufferedImage p2 = c.convolve(newArray, p1);
dk.drawPicture(p2, 0, 100);
}
}
Welcome ewuzz! I wrote a convolution using CUDA about a week ago, and the majority of my experience is with Java, so I feel qualified to provide advice for this problem.
Rather than writing all of the code for you, the best way to solve this large program is to discuss individual elements. You mentioned you are very new to programming. As the programs you write become more complex, it's essential to write small working snippets before combining them into a large successful program (or iteratively add snippets). With this being said, it's already apparent you're trying to debug a ~100 line program, and this approach will cost you time in most cases.
The first point to discuss is the general approach you mentioned. If you think about the program, what is the simplest and most repeated step? Obviously this is the kernel/mask step, so we can start from here. When you convolute each pixel, you are performing a similar option, regardless of the position (corner, edge, inside). While there are special steps necessary for these edge cases, they share similar underlying steps. If you try to write code for each of these cases separately, you will have to update the code in multiple (three) places with each adjustment and it will make the whole program more difficult to grasp.
To support my point above, here's what happened when I pasted your code into IntelliJ. This illustrates the (yellow) red flag of using the same code in multiple places:
The concrete way to fix this problem is to combine the three convolve methods into a single one and use if statements for edge-cases as necessary.
Our pseudocode with this change:
convolve(kernel, inputImage)
for each pixel in the image
convolve the single pixel and check edge cases
endfor
end
That seems pretty basic right? If we are able to successfully check edge cases, then this extremely simple logic will work. The reason I left it so general above to show how convolve the single pixel and check edge cases is logically grouped. This means it's a good candidate for extracting a method, which could look like:
private void convolvePixel(int x, int y, int[][] kernel, BufferedImage input, BufferedImage output)
Now to implement our method above, we will need to break it into a few steps, which we may then break into more steps if necessary. We'll need to look at the input image, if possible for each pixel accumulate the values using the kernel, and then set this in the output image. For brevity I will only write pseudocode from here.
convolvePixel(x, y, kernel, input, output)
accumulation = 0
for each row of kernel applicable pixels
for each column of kernel applicable pixels
if this neighboring pixel location is within the image boundaries then
input color = get the color at this neighboring pixel
adjusted value = input color * relative kernel mask value
accumulation += adjusted value
else
//handle this somehow, mentioned below
endif
endfor
endfor
set output pixel as accumulation, assuming this convolution method does not require normalization
end
The pseudocode above is already relatively long. When implementing you could write methods for the if and the else cases, but it you should be fine with this structure.
There are a few ways to handle the edge case of the else above. Your assignment probably specifies a requirement, but the fancy way is to tile around, and pretend like there's another instance of the same image next to this input image. Wikipedia explains three possibilities:
Extend - The nearest border pixels are conceptually extended as far as necessary to provide values for the convolution. Corner pixels are extended in 90° wedges. Other edge pixels are extended in lines.
Wrap - (The method I mentioned) The image is conceptually wrapped (or tiled) and values are taken from the opposite edge or corner.
Crop - Any pixel in the output image which would require values from beyond the edge is skipped. This method can result in the output image being slightly smaller, with the edges having been cropped.
A huge part of becoming a successful programmer is researching on your own. If you read about these methods, work through them on paper, run your convolvePixel method on single pixels, and compare the output to your results by hand, you will find success.
Summary:
Start by cleaning-up your code before anything.
Group the same code into one place.
Hammer out a small chunk (convolving a single pixel). Print out the result and the input values and verify they are correct.
Draw out edge/corner cases.
Read about ways to solve edge cases and decide what fits your needs.
Try implementing the else case through the same form of testing.
Call your convolveImage method with the loop, using the convolvePixel method you know works. Done!
You can look up pseudocode and even specific code to solve the exact problem, so I focused on providing general insight and strategies I have developed through my degree and personal experience. Good luck and please let me know if you want to discuss anything else in the comments below.
Java code for multiple blurs via convolution.
I am manipulating code of a image renderer that is making output image from Color[] array and my code simply update it with additional stuff right before saving, that is when the original image is actually prepared (all pixels positions prepared to be filled with RGBs in that Color[] array ready for final saving).
Reason why I am doing this is to have ability to insert text describing my render without need of another external graphics program that would do that (I want to have it all in one-go! action without need of another external app).
For that cause - as I have no reach/access for the original prepared BufferedImage (but I have access to actual Color[] that it is created from) I had to make my own class method that:
convert that original Color[] to my own temporary BufferedImage
update that temp. BufferedImage with my stuff via Graphics2D (adding some text to image)
convert my result (temp. BufferedImage with Graphics2D) back to Color[]
send that final Color[] back to the original image rendering method
that would actually make it to be the final image that is rendered out
and saved as png
Now everything works just fine as I expected except one really annoying thing that I cannot get rid off: my updated image looks very bleached-like/pale (almost no depth or shadows presented) compared to the original un-watermarked version...
To me it simply looks like after the image2color[] conversion (using #stacker's solution from here Converting Image to Color array) something goes wrong/is not right so the colors become pale and I do not have any clue why.
Here is the main part of my code that is in question:
BufferedImage sourceImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
// Color[] to BufferedImage
for (int k = 0; k < multiArrayList.size(); k++) {
// PREPARE...
int x = (int) multiArrayList.get(k)[0];
int y = (int) multiArrayList.get(k)[1];
int w = (int) multiArrayList.get(k)[2];
int h = (int) multiArrayList.get(k)[3];
Color[] data = (Color[]) multiArrayList.get(k)[4];
int border = BORDERS[k % BORDERS.length];
for (int by = 0; by < h; by++) {
for (int bx = 0; bx < w; bx++) {
if (bx == 0 || bx == w - 1) {
if (5 * by < h || 5 * (h - by - 1) < h) {
sourceImage.setRGB(x + bx, y + by, border);
}
} else if (by == 0 || by == h - 1) {
if (5 * bx < w || 5 * (w - bx - 1) < w) {
sourceImage.setRGB(x + bx, y + by, border);
}
}
}
}
// UPDATE...
for (int j = 0, index = 0; j < h; j++) {
for (int i = 0; i < w; i++, index++) {
sourceImage.setRGB(x + i, y + j, data[index].copy().toNonLinear().toRGB());
}
}
}
Graphics2D g2d = (Graphics2D) sourceImage.getGraphics();
// paints the textual watermark
drawString(g2d, text, centerX, centerY, sourceImage.getWidth());
// when saved to png at this point ALL IS JUST FINE
ImageIO.write(sourceImage, "png", new File(imageSavePath));
g2d.dispose();
// BufferedImage to Color array
int[] dt = ((DataBufferInt) sourceImage.getRaster().getDataBuffer()).getData();
bucketFull = new Color[dt.length];
for (int i = 0; i < dt.length; i++) {
bucketFull[i] = new Color(dt[i]);
}
// update and repaint output image - THIS OUTPUT IS ALREADY BLEACHED/PALE
d.ip(0, 0, width, height, renderThreads.length + 1);
d.iu(0, 0, width, height, bucketFull);
// reset objects
g2d = null;
sourceImage = null;
bucketFull = null;
multiArrayList = new ArrayList<>();
I have tested (by saving it to another .png file right after the Graphics2D addition) that before it gets that 2nd conversion it looks absolutely OK 1:1 to the original image incl. my text on that image.
But as I said when it is send for render it becomes bleached/pale that is a problem I am trying to solve.
BTW I first thought it might be that Graphics2D addition so I did try it without it but the result was the same, that is bleached/pale version.
Although my process and code is completely different the output image is basically suffering exactly the same way as in this topic (still not solved) BufferedImage color saturation
Here are my 2 examples - 1st ORIGINAL, 2nd UPDATED (bleached/pale)
As suspected, the problem is that you convert the color values from linear RGB to gamma-corrected/sRGB values when setting the RGB values to the BufferedImage, but the reverse transformation (back to linear RGB) is not done when you put the values back into the Color array.
Either change the line (inside the double for loop):
sourceImage.setRGB(x + i, y + j, data[index].copy().toNonLinear().toRGB());
to
sourceImage.setRGB(x + i, y + j, data[index].toRGB());
(you don't need the copy() any more, as you no longer mutate the values, using toNonLinear()).
This avoids the conversion altogether.
... or you could probably also change the line setting the values back, from:
bucketFull[i] = new Color(dt[i]);
to
bucketFull[i] = new Color(dt[i]).toLinear();
Arguably, this is more "correct" (as AWT treats the values as being in the sRGB color space, regardless), but I believe the first version is faster, and the difference in color is negligible. So I'd probably try the first suggested fix first, and use that unless you experience colors that are off.
public static BufferedImage split(BufferedImage img) {
BufferedImage pic = new BufferedImage(img.getWidth(), img.getHeight(), BufferedImage.TYPE_INT_RGB);
Graphics g = pic.getGraphics();
int width = 2000/2;
int height = 2000/2;
int imageW = pic.getWidth();
int imageH = pic.getHeight();
// Tile the image to fill our area.
for (int x = 0; x < width; x += imageW) {
for (int y = 0; y < height; y += imageH) {
g.drawImage(pic, x, y, null);
}
}
return pic ;
}
the point of the code is to create a tile of 2x2 of the image (same image reproduce at a smaller size in a 2x2 grid). i want to updated pic so i can print it onto a jpanel. all i get is black image. can someone tell me whats wrong with the code. or tell me how to create a better piece of code.
I want to make four smaller images of the original and place it in a grid of 2x2 that is the same size as the original image
Something like...
public static BufferedImage split(BufferedImage img) {
BufferedImage pic = new BufferedImage(img.getWidth(), img.getHeight(), BufferedImage.TYPE_INT_RGB);
Graphics g = pic.getGraphics();
int width = pic.getWidth() / 4;
int height = pic.getHeight() / 4;
Image scaled = img.getScaledInstance(width, height, Image.SCALE_SMOOTH);
// Tile the image to fill our area.
for (int x = 0; x < pic.getWidth(); x += width) {
for (int y = 0; y < pic.getHeight(); y += height) {
g.drawImage(scaled, x, y, null);
}
}
g.dispose();
return pic;
}
You may also like to have a look at Java: maintaining aspect ratio of JPanel background image and Quality of Image after resize very low -- Java for more details about how you can improve the scaling algorithm