使用java从图像中获取像素数据
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Getting pixel data from an image using java
提问by Matt
I'm trying to get the pixel rgb values from a 64 x 48bit image. I get some values but nowhere near the 3072 (= 64 x 48)values that I'm expecting. I also get:
我正在尝试从64 x 48位图获取像素 rgb 值。我得到了一些值，但与3072 (= 64 x 48)我期望的值相差甚远。我也得到：
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: Coordinate out of bounds!
at sun.awt.image.ByteInterleavedRaster.getDataElements(ByteInterleavedRaster.java:301)
at java.awt.image.BufferedImage.getRGB(BufferedImage.java:871)
at imagetesting.Main.getPixelData(Main.java:45)
at imagetesting.Main.main(Main.java:27)
I can't find the out of bounds error...
我找不到越界错误...
Here's the code:
这是代码：
package imagetesting;
import java.io.IOException;
import javax.imageio.ImageIO;
import java.io.File;
import java.awt.image.BufferedImage;
public class Main {
public static final String IMG = "matty.jpg";
public static void main(String[] args) {
BufferedImage img;
try {
img = ImageIO.read(new File(IMG));
int[][] pixelData = new int[img.getHeight() * img.getWidth()][3];
int[] rgb;
int counter = 0;
for(int i = 0; i < img.getHeight(); i++){
for(int j = 0; j < img.getWidth(); j++){
rgb = getPixelData(img, i, j);
for(int k = 0; k < rgb.length; k++){
pixelData[counter][k] = rgb[k];
}
counter++;
}
}
} catch (IOException e) {
e.printStackTrace();
}
}
private static int[] getPixelData(BufferedImage img, int x, int y) {
int argb = img.getRGB(x, y);
int rgb[] = new int[] {
(argb >> 16) & 0xff, //red
(argb >> 8) & 0xff, //green
(argb ) & 0xff //blue
};
System.out.println("rgb: " + rgb[0] + " " + rgb[1] + " " + rgb[2]);
return rgb;
}
}
采纳答案by John Kugelman
This:
这个：
for(int i = 0; i < img.getHeight(); i++){
for(int j = 0; j < img.getWidth(); j++){
rgb = getPixelData(img, i, j);
Does not match up with this:
与此不符：
private static int[] getPixelData(BufferedImage img, int x, int y) {
You have icounting the rows and jthe columns, i.e. icontains yvalues and jcontains xvalues. That's backwards.
您已经i计算了行和j列，即i包含y值并j包含x值。那是倒退。
回答by Martijn Courteaux
You have to change:
你必须改变：
for(int i = 0; i < img.getHeight(); i++){
for(int j = 0; j < img.getWidth(); j++){
rgb = getPixelData(img, i, j);
Into
进入
for(int i = 0; i < img.getWidth(); i++){
for(int j = 0; j < img.getHeight(); j++){
rgb = getPixelData(img, i, j);
Because the second parameter from getPixelDatais the x-value and the thirth is the y-value. You switched the parameters.
因为 from 的第二个参数getPixelData是x-value ，第三个参数是-value y。您切换了参数。
回答by davenpcj
I was looking for this same ability. Didn't want to enumerate the entire image, so I did some searching and used PixelGrabber.
我一直在寻找同样的能力。不想枚举整个图像，所以我做了一些搜索并使用了 PixelGrabber。
Image img = Toolkit.getDefaultToolkit().createImage(filename);
PixelGrabber pg = new PixelGrabber(img, 0, 0, -1, -1, false);
pg.grabPixels(); // Throws InterruptedException
width = pg.getWidth();
height = pg.getHeight();
int[] pixels = (int[])pg.getPixels();
You could use the int[]directly here, pixels are in a format dictated by the ColorModel from pg.getColorModel(), or you can change that false to true and force it to be RGB8-in-ints.
您可以在int[]此处直接使用，像素的格式由 ColorModel from 指定pg.getColorModel()，或者您可以将该 false 更改为 true 并强制其为 RGB8-in-int。
I've since discovered that the Rasterand Image classes can do this too, and there have been some useful classes added in javax.imageio.*.
后来我发现Raster和 Image 类也可以做到这一点，并且在javax.imageio.*.
BufferedImage img = ImageIO.read(new File(filename)); // Throws IOException
int[] pixels = img.getRGB(0,0, img.getWidth(), img.getHeight, null, 0, img.getWidth());
// also available through the BufferedImage's Raster, in multiple formats.
Raster r = img.getData();
int[] pixels = r.getPixels(0,0,r.getWidth(), r.getHeight(), (int[])null);
There are several getPixels(...)methods in Rasteras well.
里面也有几种getPixels(...)方法Raster。
回答by Richard
int argb = img.getRGB(x, y);Your code
int argb = img.getRGB(x, y);你的代码
int argb = img.getRGB(y, x);my changes now it works
int argb = img.getRGB(y, x);我的更改现在可以工作了
回答by Albus Dumbledore
Why didn't use just use:
为什么不使用只是使用：
public int[] getRGB(int startX,
int startY,
int w,
int h,
int[] rgbArray,
int offset,
int scansize)
It's built-in, man.
它是内置的，伙计。
回答by Mithusayel Murmu
This works too:
这也有效：
BufferedImage img = ImageIO.read(file);
int[] pixels = ((DataBufferInt)img.getRaster().getDataBuffer()).getData();
