Improc ass2: Added interpolation part of assignment.

improc/ass2/interpolation.py

+from math import floor, ceil
+
+bgcolor = 0
+
+def inImage(image, x, y):
+    return x >= 0 and y >= 0 and x < image.shape[0] and y < image.shape[1]
+
+def pV(image, x, y, method):
+    global bgcolor
+
+    if inImage(image, x, y):
+        if method == 'nearest':
+            return image[round(x)][round(y)]
+        elif method == 'linear':
+            x1 = floor(x)
+            x2 = ceil(x)
+            y1 = floor(y)
+            y2 = ceil(y)
+
+            return image[x1][y1] * (x2 - x) * (y2 - y) \
+                   + image[x2][y1] * (x - x1) * (y2 - y) \
+                   + image[x1][y2] * (x2 - x) * (y - y1) \
+                   + image[x2][y2] * (x - x1) * (y - y1)
+        else:
+            print 'Interpolation method "%s" is not supported' % method
+    else:
+        return bgcolor
+
+if __name__ == '__main__':
+    from pylab import linspace, show, imread, plot, array
+
+    """Profile of an image along line in n points."""
+    def profile(image, x0, y0, x1, y1, n, method):
+        return array([pV(image, x, y, method) for x, y in zip(linspace(x0, \
+            x1, n), linspace(y0, y1, n))])
+
+    a = imread('cameraman.png')
+    for method in ['nearest', 'linear']:
+        plot(profile(a, 100, 100, 120, 120, 20, method))
+    show()