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joeyajamesjoeyajames
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added heavyBlur and detectEdges functions.
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‎Image Filters/ImageFilter.java

Lines changed: 118 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -1,3 +1,25 @@
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/*******************************************************************************
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* Filter Algorithms for Java BufferedImage
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* (c) 2023, Joe James
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*
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* This program loads an image file. It has methods to:
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* - display the image in a JPanel popup window;
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* - convert the image to grayscale;
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* - scale a grayscale image to a different size;
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* - pixelate a grayscale image;
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* - apply a Gaussian blur to a grayscale image;
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* - detect edges of a grayscale image;
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* - brighten a color image.
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*
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* These files are mainly intended to accompany my series of YouTube tutorial
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* videos here, https://www.youtube.com/user/joejamesusa and are mainly
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* intended for educational purposes. You are invited to subscribe to my
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* video channel, and to download and use any code in this Java
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* repository, according to the MIT License. Feel free to post any comments
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* on my YouTube channel.
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*
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* ****************************************************************************/
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import java.util.*;
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import java.awt.*;
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import java.awt.image.*;
@@ -10,20 +32,25 @@ public class ImageFilter {
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public static void main(String[] args) {
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File file = new File("photo.png");
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//File file = new File("License Plate Photos/ca_10.jpeg");
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BufferedImage img = null;
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try { img = ImageIO.read(file); }
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catch (IOException e) { e.printStackTrace(System.out); }
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if (img != null) {
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//display(img);
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display(img);
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//img = brighten(img);
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img = toGrayScale(img);
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//img = toGrayScale2(img);
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display(img);
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//display(img);
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//img = pixelate(img);
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//img = pixelate2(img, 3);
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//img = resize(img, 150);
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img = blur(img);
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//img = blur(img);
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img = blur(blur(img));
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img = heavyblur(img);
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img = detectEdges(img);
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display(img);
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}
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}
@@ -130,7 +157,7 @@ public static BufferedImage resize (BufferedImage img, int newHeight) {
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return scaleOp.filter(img, scaledImg);
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}
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// apply Gaussian blur to a grayscale image
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// apply 3x3 Gaussian blur to a grayscale image
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public static BufferedImage blur (BufferedImage img) {
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BufferedImage blurImg = new BufferedImage(
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img.getWidth()-2, img.getHeight()-2, BufferedImage.TYPE_BYTE_GRAY);
@@ -153,6 +180,93 @@ public static BufferedImage blur (BufferedImage img) {
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return blurImg;
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}
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// apply 5x5 Gaussian blur to a grayscale image
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public static BufferedImage heavyblur (BufferedImage img) {
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BufferedImage blurImg = new BufferedImage(
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img.getWidth()-4, img.getHeight()-4, BufferedImage.TYPE_BYTE_GRAY);
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int pix = 0;
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for (int y=0; y<blurImg.getHeight(); y++) {
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for (int x=0; x<blurImg.getWidth(); x++) {
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pix = (int)(
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10*(img.getRGB(x+3, y+3)& 0xFF)
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+ 6*(img.getRGB(x+2, y+1)& 0xFF)
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+ 6*(img.getRGB(x+1, y+2)& 0xFF)
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+ 6*(img.getRGB(x+2, y+3)& 0xFF)
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+ 6*(img.getRGB(x+3, y+2)& 0xFF)
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+ 4*(img.getRGB(x+1, y+1)& 0xFF)
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+ 4*(img.getRGB(x+1, y+3)& 0xFF)
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+ 4*(img.getRGB(x+3, y+1)& 0xFF)
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+ 4*(img.getRGB(x+3, y+3)& 0xFF)
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+ 2*(img.getRGB(x, y+1)& 0xFF)
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+ 2*(img.getRGB(x, y+2)& 0xFF)
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+ 2*(img.getRGB(x, y+3)& 0xFF)
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+ 2*(img.getRGB(x+4, y+1)& 0xFF)
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+ 2*(img.getRGB(x+4, y+2)& 0xFF)
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+ 2*(img.getRGB(x+4, y+3)& 0xFF)
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+ 2*(img.getRGB(x+1, y)& 0xFF)
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+ 2*(img.getRGB(x+2, y)& 0xFF)
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+ 2*(img.getRGB(x+3, y)& 0xFF)
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+ 2*(img.getRGB(x+1, y+4)& 0xFF)
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+ 2*(img.getRGB(x+2, y+4)& 0xFF)
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+ 2*(img.getRGB(x+3, y+4)& 0xFF)
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+ (img.getRGB(x, y)& 0xFF)
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+ (img.getRGB(x, y+2)& 0xFF)
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+ (img.getRGB(x+2, y)& 0xFF)
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+ (img.getRGB(x+2, y+2)& 0xFF))/74;
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int p = (255<<24) | (pix<<16) | (pix<<8) | pix;
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blurImg.setRGB(x,y,p);
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}
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}
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return blurImg;
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}
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// detect edges of a grayscale image using Sobel algorithm
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// (for best results, apply blur before finding edges)
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public static BufferedImage detectEdges (BufferedImage img) {
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int h = img.getHeight(), w = img.getWidth(), threshold=30, p = 0;
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BufferedImage edgeImg = new BufferedImage(w, h, BufferedImage.TYPE_BYTE_GRAY);
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int[][] vert = new int[w][h];
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int[][] horiz = new int[w][h];
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int[][] edgeWeight = new int[w][h];
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for (int y=1; y<h-1; y++) {
232+
for (int x=1; x<w-1; x++) {
233+
vert[x][y] = (int)(img.getRGB(x+1, y-1)& 0xFF + 2*(img.getRGB(x+1, y)& 0xFF) + img.getRGB(x+1, y+1)& 0xFF
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- img.getRGB(x-1, y-1)& 0xFF - 2*(img.getRGB(x-1, y)& 0xFF) - img.getRGB(x-1, y+1)& 0xFF);
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horiz[x][y] = (int)(img.getRGB(x-1, y+1)& 0xFF + 2*(img.getRGB(x, y+1)& 0xFF) + img.getRGB(x+1, y+1)& 0xFF
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- img.getRGB(x-1, y-1)& 0xFF - 2*(img.getRGB(x, y-1)& 0xFF) - img.getRGB(x+1, y-1)& 0xFF);
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edgeWeight[x][y] = (int)(Math.sqrt(vert[x][y] * vert[x][y] + horiz[x][y] * horiz[x][y]));
238+
if (edgeWeight[x][y] > threshold)
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p = (255<<24) | (255<<16) | (255<<8) | 255;
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else
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p = (255<<24) | (0<<16) | (0<<8) | 0;
242+
edgeImg.setRGB(x,y,p);
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}
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}
245+
return edgeImg;
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}
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248+
// brighten color image by a percentage
249+
public static BufferedImage brighten (BufferedImage img, int percentage) {
250+
int r=0, g=0, b=0, rgb=0, p=0;
251+
int amount = (int)(percentage * 255 / 100); // rgb scale is 0-255, so 255 is 100%
252+
BufferedImage newImage = new BufferedImage(
253+
img.getWidth(), img.getHeight(), BufferedImage.TYPE_INT_ARGB);
254+
for (int y=0; y<img.getHeight(); y+=1) {
255+
for (int x=0; x<img.getWidth(); x+=1) {
256+
rgb = img.getRGB(x, y);
257+
r = ((rgb >> 16) & 0xFF) + amount;
258+
g = ((rgb >> 8) & 0xFF) + amount;
259+
b = (rgb & 0xFF) + amount;
260+
if (r>255) r=255;
261+
if (g>255) g=255;
262+
if (b>255) b=255;
263+
p = (255<<24) | (r<<16) | (g<<8) | b;
264+
newImage.setRGB(x,y,p);
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}
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}
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return newImage;
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}
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}
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