Java DIP Image Pixels - Digital image processing

What are image pixels?

An image includes two dimensional array of pixels. It is known as the value of those pixels that creates an image. While,an image can be color or grayscale.

The BufferedImage class in java is used to manage the images. For this you need to get getRGB() method of the BufferedImage class to grab the value of the pixel.

Getting Pixel Value

Use following syntax to get the value of syntax with that:

Color c = new Color(image.getRGB(j, i));

Getting RGB Values

The method getRGB() uses the row and column index as a key parameter and returns the exact pixel. To get the color image, it gives back three values which are (Red, Green, Blue). They can be get as follows:

c.getRed(); c.getGreen(); c.getBlue();

Getting Width and Height of Image

The height and width of the image can done by using the getWidth() and getHeight() methods of the BufferedImage class. Its syntax is given below:

int width = image.getWidth(); int height = image.getHeight();

The other methods to that can be supported in the BufferedImage class are described briefly:

Example

Let’s see the use of java BufferedImage class that explain the pixels of an image of size (10 x 10):

import java.awt.*; import java.awt.image.BufferedImage; import java.io.*; import javax.imageio.ImageIO; import javax.swing.JFrame; class Pixel { BufferedImage image; int width; int height; public Pixel() { try { File input = new File("blackandwhite.jpg"); image = ImageIO.read(input); width = image.getWidth(); height = image.getHeight(); int count = 0; for(int i=0; i<height; i++){ for(int j=0; j<width; j++){ count++; Color c = new Color(image.getRGB(j, i)); System.out.println("S.No: " + count + " Red: " + c.getRed() +" Green: " + c.getGreen() + " Blue: " + c.getBlue()); } } } catch (Exception e) {} } static public void main(String args[]) throws Exception { Pixel obj = new Pixel(); } }

Output

After executing the above code, it would print the pixels of the following image:

Original Image.

Pixels Output

If you scroll down the ouput, the following pattern is seen: