From 321b268bb74512289f9eb361560e8ceb9d30fe59 Mon Sep 17 00:00:00 2001
From: Santo Cariotti <santo@dcariotti.me>
Date: Tue, 16 Feb 2021 21:51:54 +0100
Subject: i&m: add operations

---
 Year_2/IandM/equalization/data/lena.png    | Bin 0 -> 473831 bytes
 Year_2/IandM/equalization/equalization.pde |  49 +++++++++++++++++++++++++++++
 2 files changed, 49 insertions(+)
 create mode 100644 Year_2/IandM/equalization/data/lena.png
 create mode 100644 Year_2/IandM/equalization/equalization.pde

(limited to 'Year_2/IandM/equalization')

diff --git a/Year_2/IandM/equalization/data/lena.png b/Year_2/IandM/equalization/data/lena.png
new file mode 100644
index 0000000..59ef68a
Binary files /dev/null and b/Year_2/IandM/equalization/data/lena.png differ
diff --git a/Year_2/IandM/equalization/equalization.pde b/Year_2/IandM/equalization/equalization.pde
new file mode 100644
index 0000000..fa7b1e2
--- /dev/null
+++ b/Year_2/IandM/equalization/equalization.pde
@@ -0,0 +1,49 @@
+void setup() {
+  size(512, 256);
+  PImage img = loadImage("lena.png");
+  img.resize(256, 256);
+  img.filter(GRAY);
+
+  image(img, 0, 0);
+  image(equalization(img), 256, 0);
+}
+
+PImage equalization(PImage I) {
+  PImage out = I.copy();
+  float[] h = histogram(out);
+
+  for (int i = 1; i < 256; ++i) {
+    h[i] = h[i]+h[i-1];
+  }
+
+  out.loadPixels();
+
+  for (int i = 0; i < out.pixels.length; ++i) {
+    out.pixels[i] = color(255*h[int(red(out.pixels[i]))]);
+  }
+
+  out.updatePixels();
+
+  return out;
+}
+
+float[] histogram(PImage I) {
+  float[] h = new float[256];
+  for (int i = 0; i< 256; ++i) { 
+    h[i] = 0;
+  }
+
+  I.loadPixels();
+
+  for (int i = 0; i < I.pixels.length; ++i) {
+    h[int(red(I.pixels[i]))]++;
+  }
+
+  for (int i = 0; i < 256; ++i) {
+    h[i] = h[i] / I.pixels.length;
+  }
+
+  I.updatePixels();
+
+  return h;
+}
-- 
cgit v1.2.3-18-g5258