i&m: add operations

1 files changed, 50 insertions, 0 deletions

diff --git a/Year_2/IandM/psnr_mse/psnr_mse.pde b/Year_2/IandM/psnr_mse/psnr_mse.pde
new file mode 100644
index 0000000..9aa0a8b
--- /dev/null
+++ b/Year_2/IandM/psnr_mse/psnr_mse.pde
@@ -0,0 +1,50 @@
+void setup() {
+  size(512, 256);
+  PImage img = loadImage("lena.png");
+  img.resize(256, 256);
+  img.filter(GRAY);
+  PImage img2 = negative(img);
+  image(img, 0, 0);
+  image(img2, 256, 0);
+
+  print("PSNR: ", psnr(img, img2));
+}
+
+float mse(PImage i1, PImage i2) {
+  float res = 0;
+  i1.loadPixels();
+  i2.loadPixels();
+
+  for (int i = 0; i < i1.pixels.length; ++i) {
+    res+= pow(red(i1.pixels[i])-red(i2.pixels[i]), 2);
+  }
+  res = res/i1.pixels.length;
+  i1.updatePixels();
+  i2.updatePixels();
+
+  return res;
+}
+
+float psnr(PImage i1, PImage i2) {
+  float mse = mse(i1, i2);
+  float res = 10*log(255*255/mse)/log(10);
+
+  return res;
+}
+
+PImage negative(PImage I) {
+  PImage out = I.copy();
+  out.loadPixels();
+  float r, g, b;
+
+  for (int i = 0; i < out.pixels.length; ++i) {
+    r= 255-red(out.pixels[i]);
+    g= 255-green(out.pixels[i]);
+    b= 255-blue(out.pixels[i]);
+
+    out.pixels[i] = color(r, g, b);
+  }
+
+  out.updatePixels();
+  return out;
+}