Spherical transform script

Author: abhinavdhere

Image_Processing/src/Geometric_transforms/people.jpg

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+'''
+Written by Abhinav Dhere (abhitechnical41[at]gmail.com).
+NOTE: Currently some part of focussed image is being lost. Bug needs to be fixed.
+'''
+from PIL import Image
+import numpy as np
+import sys
+import pdb
+
+def sphericalTransform(im, xc, yc, rmax, rho ):
+    '''
+    Apply spherical transform on image im.
+    xc,yc - center of lens ; rmax - radius ; rho - refractive index of lens.
+    '''
+    im2 = im1
+    for i in range(0,im2.shape[0]):
+        for j in range(1,im2.shape[1]):
+            dx=i-xc
+            dy=j-yc
+            r=(dx**2+dy**2)**0.5
+            z=(rmax**2-r**2)**0.5
+            Bx=(1-(1/rho))*np.arcsin(dx/((dx**2+z**2)**0.5))
+            By=(1-(1/rho))*np.arcsin(dy/((dy**2+z**2)**0.5))
+            if r<rmax:
+                t1=int(np.round(i-z*np.tan(Bx)))
+                t2=int(np.round(j-z*np.tan(By)))
+            else:
+                t1=0
+                t2=0
+            if (t1>0 and t1<im1.shape[0]) and (t2>0 and t2<im1.shape[1]):
+                im2[i,j,0] = im1[t1,t2,0]
+                im2[i,j,1] = im1[t1,t2,1]
+                im2[i,j,2] = im1[t1,t2,2]
+    return im1
+
+filename=sys.argv[1]
+xc,yc,rmax,rho=np.ravel(map(float,sys.argv[2].split(',')))
+im1 = np.array(Image.open(filename))
+print(im1.shape)
+im_trans = sphericalTransform(im1,xc,yc,rmax,rho)
+im_out = Image.fromarray(im_trans)
+im_out.show()