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comparison scripts/test-compute-object-position-from-features.py @ 334:1d90e9080cb2

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moved python scripts to the scripts directory
author Nicolas Saunier <nicolas.saunier@polymtl.ca>
date Fri, 14 Jun 2013 10:34:11 -0400
parents python/compute-object-from-features.py@04a874e1f19f
children 56cc8a1f7082
comparison
equal deleted inserted replaced
333:c9201f6b143a 334:1d90e9080cb2
1 #!/usr/bin/env python
2
3 import sys
4
5 import matplotlib.mlab as pylab
6 import matplotlib.pyplot as plt
7 import numpy as np
8
9 import cv
10 import utils
11 import cvutils
12 import ubc_utils
13 import moving
14
15 # use something like getopt to manage arguments if necessary
16
17 if len(sys.argv) < 3:
18 print('Usage: {0} <video-filename> <n-objects>'.format(sys.argv[0]))
19 sys.exit()
20
21 if sys.argv[1].endswith('.avi'):
22 videoFilenamePrefix = utils.removeExtension(sys.argv[1],'.')
23 else:
24 videoFilenamePrefix = sys.argv[1]
25
26 objectNum = int(sys.argv[2])
27
28 objects = ubc_utils.loadTrajectories(videoFilenamePrefix+'-objects.txt', objectNum+1)
29 obj = objects[objectNum]
30 features = ubc_utils.loadTrajectories(videoFilenamePrefix+'-features.txt', max(obj.featureNumbers)+1)
31 h = np.loadtxt(videoFilenamePrefix+'-homography.txt')
32
33 invh = cvutils.invertHomography(h)
34
35 def computeGroundTrajectory(features, homography, timeInterval = None):
36 '''Computes a trajectory for the set of features as the closes point to the ground
37 using the homography in image space'''
38 if not timeInterval:
39 raise Exception('not implemented') # compute from the features
40
41 yCoordinates = -np.ones((len(features),int(timeInterval.length())))
42 for i,f in enumerate(features):
43 traj = f.getPositions().asArray()
44 imgTraj = cvutils.projectArray(homography, traj)
45 yCoordinates[i,f.getFirstInstant()-timeInterval.first:f.getLastInstant()+1-timeInterval.first] = imgTraj[1,:]
46
47 indices = np.argmax(yCoordinates,0)
48 newTraj = moving.Trajectory()
49 for j,idx in enumerate(indices):
50 newTraj.addPosition(features[idx].getPositionAtInstant(j+timeInterval.first))
51 #newVelocities.addPosition(features[obj.featureNumbers[idx]].getVelocityAtInstant(j+obj.getFirstInstant()))
52
53 return newTraj
54
55 def computeMedianTrajectory(features, timeInterval = None):
56 if not timeInterval:
57 raise Exception('not implemented') # compute from the features
58
59 newTraj = moving.Trajectory()
60 for t in timeInterval:
61 points = []
62 for f in features:
63 if f.existsAtInstant(t):
64 points.append(f.getPositionAtInstant(t).aslist())
65 med = np.median(np.array(points), 0)
66 newTraj.addPositionXY(med[0], med[1])
67
68 return newTraj
69
70 # TODO version median: conversion to large matrix will not work, have to do it frame by frame
71
72 def kalmanFilter(positions, velocities, processNoiseCov, measurementNoiseCov):
73 kalman=cv.CreateKalman(6, 4)
74 kalman.transition_matrix[0,2]=1
75 kalman.transition_matrix[0,4]=1./2
76 kalman.transition_matrix[1,3]=1
77 kalman.transition_matrix[1,5]=1./2
78 kalman.transition_matrix[2,4]=1
79 kalman.transition_matrix[3,5]=1
80
81 cv.SetIdentity(kalman.measurement_matrix, 1.)
82 cv.SetIdentity(kalman.process_noise_cov, processNoiseCov)
83 cv.SetIdentity(kalman.measurement_noise_cov, measurementNoiseCov)
84 cv.SetIdentity(kalman.error_cov_post, 1.)
85
86 p = positions[0]
87 v = velocities[0]
88 v2 = velocities[2]
89 a = (v2-v).multiply(0.5)
90 kalman.state_post[0,0]=p.x
91 kalman.state_post[1,0]=p.y
92 kalman.state_post[2,0]=v.x
93 kalman.state_post[3,0]=v.y
94 kalman.state_post[4,0]=a.x
95 kalman.state_post[5,0]=a.y
96
97 filteredPositions = moving.Trajectory()
98 filteredVelocities = moving.Trajectory()
99 measurement = cv.CreateMat(4,1,cv.CV_32FC1)
100 for i in xrange(positions.length()):
101 cv.KalmanPredict(kalman) # no control
102 p = positions[i]
103 v = velocities[i]
104 measurement[0,0] = p.x
105 measurement[1,0] = p.y
106 measurement[2,0] = v.x
107 measurement[3,0] = v.y
108 cv.KalmanCorrect(kalman, measurement)
109 filteredPositions.addPositionXY(kalman.state_post[0,0], kalman.state_post[1,0])
110 filteredVelocities.addPositionXY(kalman.state_post[2,0], kalman.state_post[3,0])
111
112 return (filteredPositions, filteredVelocities)
113
114 groundTrajectory = computeGroundTrajectory([features[i] for i in obj.featureNumbers], invh, obj.getTimeInterval())
115 (filteredPositions, filteredVelocities) = kalmanFilter(groundTrajectory, obj.getVelocities(), 0.1, 0.1)
116
117 #medianTrajectory = computeMedianTrajectory([features[i] for i in obj.featureNumbers], obj.getTimeInterval())
118
119 delta = []
120 for t in obj.getTimeInterval():
121 p1 = obj.getPositionAtInstant(t)
122 p2 = groundTrajectory[t-obj.getFirstInstant()]
123 delta.append((p1-p2).aslist())
124
125 delta = np.median(delta, 0)
126
127 translated = moving.Trajectory()
128 for t in obj.getTimeInterval():
129 p1 = obj.getPositionAtInstant(t)
130 p1.x -= delta[0]
131 p1.y -= delta[1]
132 translated.addPosition(p1)
133
134 plt.clf()
135 obj.draw('rx-')
136 for fnum in obj.featureNumbers: features[fnum].draw()
137 groundTrajectory.draw('bx-')
138 filteredPositions.draw('gx-')
139 translated.draw('kx-')
140 #medianTrajectory.draw('kx-')
141 plt.axis('equal')