langs a-z

Task/Median-filter/OCaml/median-filter-1.ocaml

@@ -0,0 +1,64 @@
+let color_add (r1,g1,b1) (r2,g2,b2) =
+  ( (r1 + r2),
+    (g1 + g2),
+    (b1 + b2) )
+
+let color_div (r,g,b) d =
+  ( (r / d),
+    (g / d),
+    (b / d) )
+
+let compare_as_grayscale (r1,g1,b1) (r2,g2,b2) =
+  let v1 = (2_126 * r1 +  7_152 * g1 + 722 * b1)
+  and v2 = (2_126 * r2 +  7_152 * g2 + 722 * b2) in
+  (Pervasives.compare v1 v2)
+
+let get_rgb img x y =
+  let _, r_channel,_,_ = img in
+  let width = Bigarray.Array2.dim1 r_channel
+  and height = Bigarray.Array2.dim2 r_channel in
+  if (x < 0) || (x >= width) then (0,0,0) else
+  if (y < 0) || (y >= height) then (0,0,0) else  (* feed borders with black *)
+  (get_pixel img x y)
+
+
+let median_value img radius =
+  let samples = (radius*2+1) * (radius*2+1) in
+  fun x y ->
+    let sample = ref [] in
+
+    for _x = (x - radius) to (x + radius) do
+      for _y = (y - radius) to (y + radius) do
+
+        let v = get_rgb img _x _y in
+
+        sample := v :: !sample;
+      done;
+    done;
+
+    let ssample = List.sort compare_as_grayscale !sample in
+    let mid = (samples / 2) in
+
+    if (samples mod 2) = 1
+    then List.nth ssample (mid+1)
+    else
+      let median1 = List.nth ssample (mid)
+      and median2 = List.nth ssample (mid+1) in
+      (color_div (color_add median1 median2) 2)
+
+
+let median img radius =
+  let _, r_channel,_,_ = img in
+  let width = Bigarray.Array2.dim1 r_channel
+  and height = Bigarray.Array2.dim2 r_channel in
+
+  let _median_value = median_value img radius in
+
+  let res = new_img ~width ~height in
+  for y = 0 to pred height do
+    for x = 0 to pred width do
+      let color = _median_value x y in
+      put_pixel res color x y;
+    done;
+  done;
+  (res)

Task/Median-filter/OCaml/median-filter-2.ocaml

@@ -0,0 +1,20 @@
+let median_value img radius =
+  let samples = (radius*2+1) * (radius*2+1) in
+  let sample = Array.make samples (0,0,0) in
+  fun x y ->
+    let i = ref 0 in
+    for _x = (x - radius) to (x + radius) do
+      for _y = (y - radius) to (y + radius) do
+        let v = get_rgb img _x _y in
+        sample.(!i) <- v;
+        incr i;
+      done;
+    done;
+
+    Array.sort compare_as_grayscale sample;
+    let mid = (samples / 2) in
+
+    if (samples mod 2) = 1
+    then sample.(mid+1)
+    else (color_div (color_add sample.(mid)
+                               sample.(mid+1)) 2)