[python-dtcwt] 198/497: made 3d_dtcwt_directionality a runnable demo

[Ghislain Vaillant]

This is an automated email from the git hooks/post-receive script.

ghisvail-guest pushed a commit to branch debian/sid
in repository python-dtcwt.

commit ec1d5bdf3c70b98664d9271b125b94f48d71a019
Author: tim <timothy.daniel.roberts at gmail.com>
Date:   Wed Nov 13 00:54:30 2013 +0000

    made 3d_dtcwt_directionality a runnable demo
---
 examples/3d_dtcwt_directionality.py | 147 +++++++++++++++++++-----------------
 1 file changed, 76 insertions(+), 71 deletions(-)

diff --git a/examples/3d_dtcwt_directionality.py b/examples/3d_dtcwt_directionality.py
index 7142f8e..bd3cebf 100644
--- a/examples/3d_dtcwt_directionality.py
+++ b/examples/3d_dtcwt_directionality.py
@@ -19,82 +19,87 @@ from mpl_toolkits.mplot3d.art3d import Poly3DCollection
 from dtcwt import dtwavexfm3, dtwaveifm3, biort, qshift
 
 # Specify details about sphere and grid size
-GRID_SIZE = 128
-SPHERE_RAD = int(0.45 * GRID_SIZE) + 0.5
-
-# Compute an image of the sphere
-grid = np.arange(-(GRID_SIZE>>1), GRID_SIZE>>1)
-X, Y, Z = np.meshgrid(grid, grid, grid)
-r = np.sqrt(X*X + Y*Y + Z*Z)
-sphere = (0.5 + np.clip(SPHERE_RAD-r, -0.5, 0.5)).astype(np.float32)
-
-# Specify number of levels and wavelet family to use
-nlevels = 2
-b = biort('near_sym_a')
-q = qshift('qshift_a')
-
-# Form the DT-CWT of the sphere. We use discard_level_1 since we're
-# uninterested in the inverse transform and this saves us some memory.
-Yl, Yh = dtwavexfm3(sphere, nlevels, b, q, discard_level_1=True)
-
-# Plot maxima
-figure(figsize=(8,8))
-
-ax = gcf().add_subplot(1,1,1, projection='3d')
-ax.set_aspect('equal')
-ax.view_init(35, 75)
-
-# Plot unit sphere +ve octant
-thetas = np.linspace(0, np.pi/2, 10)
-phis = np.linspace(0, np.pi/2, 10)
+def main():
+    GRID_SIZE = 128
+    SPHERE_RAD = int(0.45 * GRID_SIZE) + 0.5
+    
+    # Compute an image of the sphere
+    grid = np.arange(-(GRID_SIZE>>1), GRID_SIZE>>1)
+    X, Y, Z = np.meshgrid(grid, grid, grid)
+    r = np.sqrt(X*X + Y*Y + Z*Z)
+    sphere = (0.5 + np.clip(SPHERE_RAD-r, -0.5, 0.5)).astype(np.float32)
+    
+    # Specify number of levels and wavelet family to use
+    nlevels = 2
+    b = biort('near_sym_a')
+    q = qshift('qshift_a')
+    
+    # Form the DT-CWT of the sphere. We use discard_level_1 since we're
+    # uninterested in the inverse transform and this saves us some memory.
+    Yl, Yh = dtwavexfm3(sphere, nlevels, b, q, discard_level_1=False)
+    
+    # Plot maxima
+    figure(figsize=(8,8))
+    
+    ax = gcf().add_subplot(1,1,1, projection='3d')
+    ax.set_aspect('equal')
+    ax.view_init(35, 75)
+    
+    # Plot unit sphere +ve octant
+    thetas = np.linspace(0, np.pi/2, 10)
+    phis = np.linspace(0, np.pi/2, 10)
+  
+    
+    tris = []
+    rad = 0.99 # so that points plotted latter are not z-clipped
+    for t1, t2 in zip(thetas[:-1], thetas[1:]):
+        for p1, p2 in zip(phis[:-1], phis[1:]):
+            tris.append([
+                sphere_to_xyz(rad, t1, p1),
+                sphere_to_xyz(rad, t1, p2),
+                sphere_to_xyz(rad, t2, p2),
+                sphere_to_xyz(rad, t2, p1),
+                ])
+            
+    sphere = Poly3DCollection(tris, facecolor='w', edgecolor=(0.6,0.6,0.6))
+    ax.add_collection3d(sphere)
+            
+    locs = []
+    scale = 1.1
+    for idx in xrange(Yh[-1].shape[3]):
+        Z = Yh[-1][:,:,:,idx]
+        C = np.abs(Z)
+        max_loc = np.asarray(np.unravel_index(np.argmax(C), C.shape)) - np.asarray(C.shape)*0.5
+        max_loc /= np.sqrt(np.sum(max_loc * max_loc))
+        
+        # Only record directions in the +ve octant (or those from the -ve quadrant
+        # which can be flipped).
+        if np.all(np.sign(max_loc) == 1):
+            locs.append(max_loc)
+            ax.text(max_loc[0] * scale, max_loc[1] * scale, max_loc[2] * scale, str(idx+1))
+        elif np.all(np.sign(max_loc) == -1):
+            locs.append(-max_loc)
+            ax.text(-max_loc[0] * scale, -max_loc[1] * scale, -max_loc[2] * scale, str(idx+1))
+            
+            # Plot all directions as a scatter plot
+    locs = np.asarray(locs)
+    ax.scatter(locs[:,0], locs[:,1], locs[:,2], c=np.arange(locs.shape[0]))
+    
+    w = 1.1
+    ax.auto_scale_xyz([0, w], [0, w], [0, w])
+    
+    legend()
+    title('3D DT-CWT subband directions for +ve hemisphere quadrant')
+    tight_layout()
+    
+    show()
 
 def sphere_to_xyz(r, theta, phi):
     st, ct = np.sin(theta), np.cos(theta)
     sp, cp = np.sin(phi), np.cos(phi)
     return r * np.asarray((st*cp, st*sp, ct))
 
-tris = []
-rad = 0.99 # so that points plotted latter are not z-clipped
-for t1, t2 in zip(thetas[:-1], thetas[1:]):
-    for p1, p2 in zip(phis[:-1], phis[1:]):
-        tris.append([
-            sphere_to_xyz(rad, t1, p1),
-            sphere_to_xyz(rad, t1, p2),
-            sphere_to_xyz(rad, t2, p2),
-            sphere_to_xyz(rad, t2, p1),
-        ])
-
-sphere = Poly3DCollection(tris, facecolor='w', edgecolor=(0.6,0.6,0.6))
-ax.add_collection3d(sphere)
-
-locs = []
-scale = 1.1
-for idx in xrange(Yh[-1].shape[3]):
-    Z = Yh[-1][:,:,:,idx]
-    C = np.abs(Z)
-    max_loc = np.asarray(np.unravel_index(np.argmax(C), C.shape)) - np.asarray(C.shape)*0.5
-    max_loc /= np.sqrt(np.sum(max_loc * max_loc))
-
-    # Only record directions in the +ve octant (or those from the -ve quadrant
-    # which can be flipped).
-    if np.all(np.sign(max_loc) == 1):
-        locs.append(max_loc)
-        ax.text(max_loc[0] * scale, max_loc[1] * scale, max_loc[2] * scale, str(idx+1))
-    elif np.all(np.sign(max_loc) == -1):
-        locs.append(-max_loc)
-        ax.text(-max_loc[0] * scale, -max_loc[1] * scale, -max_loc[2] * scale, str(idx+1))
- 
-# Plot all directions as a scatter plot
-locs = np.asarray(locs)
-ax.scatter(locs[:,0], locs[:,1], locs[:,2], c=np.arange(locs.shape[0]))
-
-w = 1.1
-ax.auto_scale_xyz([0, w], [0, w], [0, w])
-
-legend()
-title('3D DT-CWT subband directions for +ve hemisphere quadrant')
-tight_layout()
-
-show()
+if __name__ == '__main__':
+    main()
 
 # vim:sw=4:sts=4:et

-- 
Alioth's /usr/local/bin/git-commit-notice on /srv/git.debian.org/git/debian-science/packages/python-dtcwt.git