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comparison python/cvutils.py @ 98:b85912ab4064

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refactored projection functions
author Nicolas Saunier <nicolas.saunier@polymtl.ca>
date Tue, 12 Jul 2011 16:43:33 -0400
parents 40e8e3bb3702
children e7dc5a780f09
comparison
equal deleted inserted replaced
97:b3a1c26e2f22 98:b85912ab4064
22 del draw 22 del draw
23 23
24 #out = utils.openCheck(resultFilename) 24 #out = utils.openCheck(resultFilename)
25 img.save(resultFilename) 25 img.save(resultFilename)
26 26
27 def projectArray(homography, points):
28 '''Returns the coordinates of the projected points (format 2xN points)
29 through homography'''
30 from numpy.core._dotblas import dot
31 from numpy.core.multiarray import array
32 from numpy.lib.function_base import append
33
34 if points.shape[0] != 2:
35 raise Exception('points of dimension {0} {1}'.format(points.shape[0], points.shape[1]))
36
37 if (homography!=None) and homography.size>0:
38 augmentedPoints = append(points,[[1]*points.shape[1]], 0)
39 prod = dot(homography, augmentedPoints)
40 return prod[0:2]/prod[2]
41 else:
42 return p
43
27 def project(homography, p): 44 def project(homography, p):
28 '''Returns the coordinates of the projection of the point p 45 '''Returns the coordinates of the projection of the point p
29 through homography''' 46 through homography'''
30 from numpy.core._dotblas import dot
31 from numpy.core.multiarray import array 47 from numpy.core.multiarray import array
32 from numpy.lib.function_base import insert 48 return projectArray(homography, array([[p[0]],p[1]]))
33 if (homography!=None) and (len(homography)>0):
34 pAugmented = insert(array(p), [2],[1], axis=0)
35 tmp = dot(homography, pAugmented)
36 return [tmp[0]/tmp[2], tmp[1]/tmp[2]]
37 else:
38 return p
39 49
40 def projectTrajectory(homography, trajectory): 50 def projectTrajectory(homography, trajectory):
41 '''Projects a series of points in the format 51 '''Projects a series of points in the format
42 [[x1, x2, ...], 52 [[x1, x2, ...],
43 [y1, y2, ...]] 53 [y1, y2, ...]]'''
44 54 from numpy.core.multiarray import array
45 Warning: not optimized, calls project()''' 55 return projectArray(homography, array(trajectory))
46 projected = [[],[]]
47 for x, y in zip(trajectory[0], trajectory[1]):
48 p = [x,y]
49 pp = project(homography, p)
50 projected[0].append(pp[0])
51 projected[1].append(pp[1])
52 return projected
53 56
54 def invertHomography(homography): 57 def invertHomography(homography):
55 'Returns an inverted homography' 58 'Returns an inverted homography'
56 from numpy.linalg.linalg import inv 59 from numpy.linalg.linalg import inv
57 invH = inv(homography) 60 invH = inv(homography)