smartblur convolution experiment

1 files changed, 162 insertions, 0 deletions

diff --git a/smartblur.java b/smartblur.java
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+++ b/smartblur.java
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+import java.awt.image.Kernel;
+import java.awt.image.BufferedImage;
+import java.awt.image.ConvolveOp;
+import java.awt.Graphics;
+
+// http://asserttrue.blogspot.ca/2010/08/implementing-smart-blur-in-java.html
+public class SmartBlurFilter
+{
+  double SENSITIVITY = 10;
+  int REGION_SIZE = 5;
+
+  float[] kernelArray =
+  {
+    1,1,1,1,1,1,1,1,1,
+    1,1,1,1,1,1,1,1,1,
+    1,1,1,1,1,1,1,1,1,
+    1,1,1,1,1,1,1,1,1,
+    1,1,1,1,1,1,1,1,1,
+    1,1,1,1,1,1,1,1,1,
+    1,1,1,1,1,1,1,1,1,
+    1,1,1,1,1,1,1,1,1,
+    1,1,1,1,1,1,1,1,1
+  };
+
+  Kernel kernel = new Kernel(9, 9, normalizeKernel(kernelArray));
+
+  float[] normalizeKernel(float[] ar)
+  {
+    int n = 0;
+    for (int i = 0; i < ar.length; i++)
+      n += ar[i];
+    for (int i = 0; i < ar.length; i++)
+      ar[i] /= n;
+
+    return ar;
+  }
+
+  public double lerp(double a,double b, double amt)
+  {
+    return a + amt * (b - a);
+  }
+
+  public double getLerpAmount(double a, double cutoff)
+  {
+    if (a > cutoff)
+    return 1.0;
+
+    return a / cutoff;
+  }
+
+  public double rmsError(int[] pixels)
+  {
+    double ave = 0;
+
+    for (int i = 0; i < pixels.length; i++)
+    ave += (pixels[ i ] >> 8) & 255;
+
+    ave /= pixels.length;
+
+    double diff = 0;
+    double accumulator = 0;
+
+    for (int i = 0; i < pixels.length; i++)
+    {
+         diff = ((pixels[ i ] >> 8) & 255) - ave;
+         diff *= diff;
+         accumulator += diff;
+    }
+
+    double rms = accumulator / pixels.length;
+
+    rms = Math.sqrt(rms);
+
+    return rms;
+  }
+
+  int[] getSample(BufferedImage image, int x, int y, int size)
+  {
+    int[] pixels = {};
+
+    try
+    {
+      BufferedImage subimage = image.getSubimage(x,y, size, size);
+      pixels = subimage.getRGB(0,0,size,size,null,0,size);
+    }
+    catch(Exception e)
+    {
+         // will arrive here if we requested
+         // pixels outside the image bounds
+    }
+    return pixels;
+  }
+
+  int lerpPixel(int oldpixel, int newpixel, double amt)
+  {
+    int oldRed = (oldpixel >> 16) & 255;
+    int newRed = (newpixel >> 16) & 255;
+    int red = (int) lerp((double)oldRed, (double)newRed, amt) & 255;
+
+    int oldGreen = (oldpixel >> 8) & 255;
+    int newGreen = (newpixel >> 8) & 255;
+    int green = (int) lerp((double)oldGreen, (double)newGreen, amt) & 255;
+
+    int oldBlue = oldpixel & 255;
+    int newBlue = newpixel & 255;
+    int blue = (int) lerp((double)oldBlue, (double)newBlue, amt) & 255;
+
+    return (red << 16) | (green << 8) | blue;
+  }
+
+  int[] blurImage(BufferedImage image, int[] orig, int[] blur, double sensitivity)
+  {
+    int newPixel = 0;
+    double amt = 0;
+    int size = REGION_SIZE;
+
+    for (int i = 0; i < orig.length; i++)
+    {
+         int w = image.getWidth();
+         int[] pix = getSample(image, i % w, i / w, size);
+         if (pix.length == 0)
+         continue;
+
+         amt = getLerpAmount (rmsError(pix), sensitivity);
+         newPixel = lerpPixel(blur[ i ], orig[ i ],  amt);
+         orig[ i ] = newPixel;
+    }
+
+    return orig;
+  }
+
+
+  public BufferedImage filter(BufferedImage image)
+  {
+    ConvolveOp convolver = new ConvolveOp(kernel, ConvolveOp.EDGE_NO_OP, null);
+
+    // clone image into target
+    BufferedImage target = new BufferedImage(image.getWidth(), image.getHeight(), image.getType());
+    Graphics g = target.createGraphics();
+    g.drawImage(image, 0, 0, null);
+    g.dispose();
+
+    int w = target.getWidth();
+    int h = target.getHeight();
+
+    // get source pixels
+    int[] pixels = image.getRGB(0, 0, w, h, null, 0, w);
+
+    // blur the cloned image
+    target = convolver.filter(target, image);
+
+    // get the blurred pixels
+    int[] blurryPixels = target.getRGB(0, 0, w, h, null, 0, w);
+
+    // go thru the image and interpolate values
+    pixels = blurImage(image, pixels, blurryPixels, SENSITIVITY);
+
+    // replace original pixels with new ones
+    image.setRGB(0, 0, w, h, pixels, 0, w);
+    return image;
+  }
+}
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