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Image Processing in Java – Colored to Red Green Blue Image Conversion

  • Difficulty Level : Medium
  • Last Updated : 14 Nov, 2021

Prerequisites: 

In this set, we will be converting a colored image to an image with either red effect, green effect, or blue effect.

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Colored Image – The colored image or RGB color model is an additive mixing model in which red, green, and blue light are added together in various ways to reproduce a broad array of colors. 

The basic idea is to get the pixel value for each coordinate and then keep the desired resultant color pixel value to be the same and set the other two as zero.



Converting to Red Colored Image 

Algorithm:

  1. Get the RGB value of the pixel.
  2. Set the RGB values as follows: 
    • R: NO CHANGE
    • G: Set to 0
    • B: Set to 0
  3. Replace the R, G, and B values of the pixel with the values calculated in step 2.
  4. Repeat Step 1 to Step 3 for each pixel of the image.

Implementation:

Java




// Java program to demonstrate colored
// to red colored image conversion
  
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
  
public class RedImage {
    public static void main(String args[])
        throws IOException
    {
        BufferedImage img = null;
        File f = null;
  
        // read image
        try {
            f = new File(
                "C:/Users/hp/Desktop/Image Processing in Java/gfg-logo.png");
            img = ImageIO.read(f);
        }
        catch (IOException e) {
            System.out.println(e);
        }
  
        // get width and height
        int width = img.getWidth();
        int height = img.getHeight();
  
        // convert to red image
        for (int y = 0; y < height; y++) {
            for (int x = 0; x < width; x++) {
                int p = img.getRGB(x, y);
  
                int a = (p >> 24) & 0xff;
                int r = (p >> 16) & 0xff;
  
                // set new RGB keeping the r
                // value same as in original image
                // and setting g and b as 0.
                p = (a << 24) | (r << 16) | (0 << 8) | 0;
  
                img.setRGB(x, y, p);
            }
        }
  
        // write image
        try {
            f = new File(
                "C:/Users/hp/Desktop/Image Processing in Java/GFG.png");
            ImageIO.write(img, "png", f);
        }
        catch (IOException e) {
            System.out.println(e);
        }
    }
}

Output – 

Note: This code will not run on an online IDE as it needs an image on a disk. 

Converting to Green Colored Image 

Algorithm

  1. Get the RGB value of the pixel.
  2. Set the RGB values as follows: 
    • R: Set to 0
    • G: NO CHANGE
    • B: Set to 0
  3. Replace the R, G, and B values of the pixel with the values calculated in step 2.
  4. Repeat Step 1 to Step 3 for each pixel of the image.

Implementation:

Java




// Java program to demonstrate colored
// to green coloured image conversion
  
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
  
public class GreenImage {
    public static void main(String args[])
        throws IOException
    {
        BufferedImage img = null;
        File f = null;
  
        // read image
        try {
            f = new File(
                "C:/Users/hp/Desktop/Image Processing in Java/gfg-logo.png");
            img = ImageIO.read(f);
        }
        catch (IOException e) {
            System.out.println(e);
        }
  
        // get width and height
        int width = img.getWidth();
        int height = img.getHeight();
  
        // convert to green image
        for (int y = 0; y < height; y++) {
            for (int x = 0; x < width; x++) {
                int p = img.getRGB(x, y);
  
                int a = (p >> 24) & 0xff;
                int g = (p >> 8) & 0xff;
  
                // set new RGB
                // keeping the g value same as in original
                // image and setting r and b as 0.
                p = (a << 24) | (0 << 16) | (g << 8) | 0;
  
                img.setRGB(x, y, p);
            }
        }
  
        // write image
        try {
            f = new File(
                "C:/Users/hp/Desktop/Image Processing in Java/GFG.png");
            ImageIO.write(img, "png", f);
        }
        catch (IOException e) {
            System.out.println(e);
        }
    }
}

Output – 

Note: This code will not run on an online IDE as it needs an image on a disk. 

Converting to Blue Colored Image 

Algorithm 

  1. Get the RGB value of the pixel.
  2. Set the RGB values as follows: 
    • R: Set to 0
    • G: Set to 0
    • B: NO CHANGE
  3. Replace the R, G, and B values of the pixel with the values calculated in step 2.
  4. Repeat Step 1 to Step 3 for each pixel of the image.

Implementation

Java




// Java program to demonstrate colored
// to blue coloured image conversion
  
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
  
public class BlueImage {
    public static void main(String args[])
        throws IOException
    {
        BufferedImage img = null;
        File f = null;
  
        // read image
        try {
            f = new File(
                "C:/Users/hp/Desktop/Image Processing in Java/gfg-logo.png");
            img = ImageIO.read(f);
        }
        catch (IOException e) {
            System.out.println(e);
        }
  
        // get width and height
        int width = img.getWidth();
        int height = img.getHeight();
  
        // convert to blue image
        for (int y = 0; y < height; y++) {
            for (int x = 0; x < width; x++) {
                int p = img.getRGB(x, y);
  
                int a = (p >> 24) & 0xff;
                int b = p & 0xff;
  
                // set new RGB
                // keeping the b value same as in original
                // image and setting r and g as 0.
                p = (a << 24) | (0 << 16) | (0 << 8) | b;
  
                img.setRGB(x, y, p);
            }
        }
  
        // write image
        try {
            f = new File(
                "C:/Users/hp/Desktop/Image Processing in Java/GFG.png");
            ImageIO.write(img, "png", f);
        }
        catch (IOException e) {
            System.out.println(e);
        }
    }
}

Output – 

Note: This code will not run on an online IDE as it needs an image on a disk. 

This article is contributed by Pratik Agarwal. If you like GeeksforGeeks and would like to contribute, you can also write an article using write.geeksforgeeks.org or mail your article to review-team@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks. Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above.




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