[Python-modules-commits] [python-pysolar] 03/11: Added code for detecting angle to solar obstructions from spherically distorted images

[Wolfgang Borgert]

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debacle pushed a commit to annotated tag 0.4.0
in repository python-pysolar.

commit 28f78a082195b123391dd3f0cf84264439d45e79
Author: Brandon Stafford <brandon at pingswept.org>
Date:   Mon Mar 16 19:14:26 2009 -0400

    Added code for detecting angle to solar obstructions from spherically distorted images
---
 horizon.py | 82 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 82 insertions(+)

diff --git a/horizon.py b/horizon.py
new file mode 100644
index 0000000..811a4ad
--- /dev/null
+++ b/horizon.py
@@ -0,0 +1,82 @@
+#!/usr/bin/python
+ 
+# Script for detecting angle to solar obstructions from
+# spherically distorted images
+ 
+# Copyright 2009 Brandon Stafford
+#
+# This file is part of Pysolar.
+#
+# Pysolar is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# Pysolar is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with Pysolar. If not, see <http://www.gnu.org/licenses/>.
+
+from PIL import Image
+from math import *
+import numpy as np
+
+def squareImage(im):
+    (width, height) = im.size
+    box = ((width - height)/2, 0, (width + height)/2, height)
+    return im.crop(box)
+
+def despherifyImage(im):
+    (width, height) = im.size
+    half_width = im.size[0]/2
+    half_height = im.size[1]/2
+
+    inpix = im.load()
+    out = Image.new("L", (width, half_height))
+    outpix = out.load()
+
+    full_circle = 1000.0 * 2 * pi
+
+    for r in range(half_width):
+        for theta in range(int(full_circle)):
+            (inx, iny) = (round(r * cos(theta/1000.0)) + half_width, round(r * sin(theta/1000.0)) + half_width)
+            (outx, outy) = (width - width * (theta/full_circle) - 1, r)
+            outpix[outx, outy] = inpix[inx, iny]
+    return out
+
+def differentiateImageColumns(im):
+    (width, height) = im.size
+    pix = im.load()
+
+    for x in range(width):
+        for y in range(height - 1):
+            pix[x, y] = min(10 * abs(pix[x, y] - pix[x, y + 1]), 255)
+
+    return im
+
+def redlineImage(im):
+    (width, height) = im.size
+    pix = im.load()
+
+    threshold = 300
+
+    for x in range(width):
+        for y in range(height - 1):
+            (R, G, B) = pix[x, y]
+            if R + G + B > threshold:
+                pix[x, y] = (255, 0, 0)
+                break
+    return im
+
+im = Image.open('spherical.jpg').convert("L")
+im = squareImage(im)
+
+lin = despherifyImage(im)
+d = differentiateImageColumns(lin).convert("RGB")
+r = redlineImage(d)
+
+r.show()
+

-- 
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