3 * mtp is the ``Multi Tracked Paths'', an implementation of the
4 * k-shortest paths algorithm for multi-target tracking.
6 * Copyright (c) 2012 Idiap Research Institute, http://www.idiap.ch/
7 * Written by Francois Fleuret <francois.fleuret@idiap.ch>
9 * This file is part of mtp.
11 * mtp is free software: you can redistribute it and/or modify it
12 * under the terms of the GNU General Public License version 3 as
13 * published by the Free Software Foundation.
15 * mtp is distributed in the hope that it will be useful, but WITHOUT
16 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
17 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
18 * License for more details.
20 * You should have received a copy of the GNU General Public License
21 * along with selector. If not, see <http://www.gnu.org/licenses/>.
30 #include "mtp_tracker.h"
32 //////////////////////////////////////////////////////////////////////
34 scalar_t noisy_score(scalar_t true_score, scalar_t erroneous_score,
35 scalar_t score_noise, scalar_t flip_noise) {
36 if(drand48() < flip_noise) {
37 return erroneous_score + score_noise * (2.0 * drand48() - 1.0);
39 return true_score + score_noise * (2.0 * drand48() - 1.0);
43 int main(int argc, char **argv) {
45 int nb_time_steps = 8;
46 int motion_amplitude = 1;
48 MTPTracker *tracker = new MTPTracker();
50 tracker->allocate(nb_time_steps, nb_locations);
52 // We define the spatial structure by stating what are the possible
53 // motions of targets, and what are the entrances and the exits.
55 // Here our example is a 1D space with motions from any location to
56 // any location less than motion_amplitude away, entrance at
57 // location 0 and exit at location nb_locations-1.
59 for(int l = 0; l < nb_locations; l++) {
60 for(int k = 0; k < nb_locations; k++) {
61 tracker->allowed_motion[l][k] = abs(l - k) <= motion_amplitude;
63 tracker->entrances[0] = 1;
64 tracker->exits[nb_locations - 1] = 1;
67 tracker->force_empty_first_frame = 0;
68 tracker->force_empty_last_frame = 0;
70 // We construct the graph corresponding to this structure
72 tracker->build_graph();
74 // Then, we specify for every location and time step what is the
75 // detection score there.
77 scalar_t flip_noise = 0.05;
78 scalar_t score_noise = 0.0;
80 // We first put a background noise, with negative scores at every
83 for(int t = 0; t < nb_time_steps; t++) {
84 for(int l = 0; l < nb_locations; l++) {
85 tracker->detection_scores[t][l] = noisy_score(-1.0, 1.0, score_noise, flip_noise);
89 // Then we add two targets with a typical tracking local minimum
91 // * Target A moves from location 0 to the middle, stays there for a
92 // while, and comes back. It is strongly detected on the first
95 // * Target B moves from location nb_locations-1 to the middle, stay
96 // there for a while, and comes back. It is strongly detected on
99 int la, lb; // Target locations
100 scalar_t sa, sb; // Target detection scores
101 for(int t = 0; t < nb_time_steps; t++) {
102 if(t < nb_time_steps/2) {
104 lb = nb_locations - 1 - t;
105 sa = noisy_score(10.0, -1.0, score_noise, flip_noise);
106 sb = noisy_score( 1.0, -1.0, score_noise, flip_noise);
108 la = nb_time_steps - 1 - t;
109 lb = t - nb_time_steps + nb_locations;
110 sa = noisy_score( 1.0, -1.0, score_noise, flip_noise);
111 sb = noisy_score(10.0, -1.0, score_noise, flip_noise);
114 if(la > nb_locations/2 - 1) la = nb_locations/2 - 1;
115 if(lb < nb_locations/2 + 1) lb = nb_locations/2 + 1;
117 tracker->detection_scores[t][la] = sa;
118 tracker->detection_scores[t][lb] = sb;
121 { // Write down the tracker setting, so that we can use it as an
122 // example for the mtp command line
123 ofstream out_tracker("tracker.dat");
124 tracker->write(&out_tracker);
127 // Performs the tracking per se
131 // Prints the detected trajectories
133 for(int t = 0; t < tracker->nb_trajectories(); t++) {
134 cout << "Trajectory "
136 << " starting at " << tracker->trajectory_entrance_time(t)
137 << ", duration " << tracker->trajectory_duration(t)
138 << ", score " << tracker->trajectory_score(t)
139 << ", through nodes ";
140 for(int u = 0; u < tracker->trajectory_duration(t); u++) {
141 cout << " " << tracker->trajectory_location(t, u);