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/>.
25 #include "mtp_tracker.h"
31 void MTPTracker::free() {
32 delete[] _edge_lengths;
34 deallocate_array<scalar_t>(detection_scores);
35 deallocate_array<int>(allowed_motion);
40 void MTPTracker::allocate(int nb_time_steps, int nb_locations) {
43 _nb_locations = nb_locations;
44 _nb_time_steps = nb_time_steps;
46 detection_scores = allocate_array<scalar_t>(_nb_time_steps, _nb_locations);
47 allowed_motion = allocate_array<int>(_nb_locations, _nb_locations);
49 entrances = new int[_nb_locations];
50 exits = new int[_nb_locations];
52 for(int l = 0; l < _nb_locations; l++) {
55 for(int m = 0; m < _nb_locations; m++) {
56 allowed_motion[l][m] = 0;
60 for(int t = 0; t < _nb_time_steps; t++) {
61 for(int l = 0; l < _nb_locations; l++) {
62 detection_scores[t][l] = 0.0;
70 void MTPTracker::write(ostream *os) {
71 (*os) << _nb_locations << " " << _nb_time_steps <<endl;
75 for(int l = 0; l < _nb_locations; l++) {
76 for(int m = 0; m < _nb_locations; m++) {
77 (*os) << allowed_motion[l][m];
78 if(m < _nb_locations - 1) (*os) << " "; else (*os) << endl;
84 for(int l = 0; l < _nb_locations; l++) {
85 (*os) << entrances[l];
86 if(l < _nb_locations - 1) (*os) << " "; else (*os) << endl;
91 for(int l = 0; l < _nb_locations; l++) {
93 if(l < _nb_locations - 1) (*os) << " "; else (*os) << endl;
98 for(int t = 0; t < _nb_time_steps; t++) {
99 for(int l = 0; l < _nb_locations; l++) {
100 (*os) << detection_scores[t][l];
101 if(l < _nb_locations - 1) (*os) << " "; else (*os) << endl;
106 void MTPTracker::read(istream *is) {
107 int nb_locations, nb_time_steps;
109 (*is) >> nb_locations >> nb_time_steps;
111 allocate(nb_time_steps, nb_locations);
113 for(int l = 0; l < _nb_locations; l++) {
114 for(int m = 0; m < _nb_locations; m++) {
115 (*is) >> allowed_motion[l][m];
119 for(int l = 0; l < _nb_locations; l++) {
120 (*is) >> entrances[l];
123 for(int l = 0; l < _nb_locations; l++) {
127 for(int t = 0; t < _nb_time_steps; t++) {
128 for(int l = 0; l < _nb_locations; l++) {
129 (*is) >> detection_scores[t][l];
134 void MTPTracker::write_trajectories(ostream *os) {
135 for(int t = 0; t < nb_trajectories(); t++) {
137 << " " << trajectory_entrance_time(t)
138 << " " << trajectory_duration(t)
139 << " " << trajectory_score(t);
140 for(int u = 0; u < trajectory_duration(t); u++) {
141 (*os) << " " << trajectory_location(t, u);
147 MTPTracker::MTPTracker() {
151 detection_scores = 0;
161 MTPTracker::~MTPTracker() {
162 delete[] _edge_lengths;
164 deallocate_array<scalar_t>(detection_scores);
165 deallocate_array<int>(allowed_motion);
170 int MTPTracker::early_pair_node(int t, int l) {
171 return 1 + (2 * (t + 0) + 0) * _nb_locations + l;
174 int MTPTracker::late_pair_node(int t, int l) {
175 return 1 + (2 * (t + 0) + 1) * _nb_locations + l;
178 void MTPTracker::build_graph() {
179 // Delete the existing graph if there was one
180 delete[] _edge_lengths;
183 int nb_motions = 0, nb_exits = 0, nb_entrances = 0;
185 for(int l = 0; l < _nb_locations; l++) {
186 if(exits[l]) nb_exits++;
187 if(entrances[l]) nb_entrances++;
188 for(int m = 0; m < _nb_locations; m++) {
189 if(allowed_motion[l][m]) nb_motions++;
193 int nb_vertices = 2 + 2 * _nb_time_steps * _nb_locations;
196 // The edges from the source to the first frame, and from the last
199 // The edges from the source to the entrances and from the exits
200 // to the sink (in every time frames but the first for the
201 // entrances, and last for the exits)
202 (_nb_time_steps - 1) * (nb_exits + nb_entrances) +
203 // The edges for the motions, between every successive frames
204 (_nb_time_steps - 1) * nb_motions +
205 // The edges inside the duplicated nodes
206 _nb_locations * _nb_time_steps;
208 int *node_from = new int[nb_edges];
209 int *node_to = new int[nb_edges];
211 int source = 0, sink = nb_vertices - 1;
214 _edge_lengths = new scalar_t[nb_edges];
216 // We put the in-node edges first, since these are the ones whose
217 // lengths we will have to change before tracking, according to the
220 for(int t = 0; t < _nb_time_steps; t++) {
221 for(int l = 0; l < _nb_locations; l++) {
222 node_from[e] = early_pair_node(t, l);
223 node_to[e] = late_pair_node(t, l);
228 // The edges from the source to the first time frame
230 for(int l = 0; l < _nb_locations; l++) {
231 node_from[e] = source;
232 node_to[e] = 1 + l + 0 * _nb_locations;
233 _edge_lengths[e] = 0.0;
237 // The edges from the last frame to the sink
239 for(int l = 0; l < _nb_locations; l++) {
240 node_from[e] = late_pair_node(_nb_time_steps - 1, l);
242 _edge_lengths[e] = 0.0;
246 // The edges between frames, corresponding to allowed motions
248 for(int t = 0; t < _nb_time_steps - 1; t++) {
249 for(int l = 0; l < _nb_locations; l++) {
250 for(int k = 0; k < _nb_locations; k++) {
251 if(allowed_motion[l][k]) {
252 node_from[e] = late_pair_node(t, l);
253 node_to[e] = early_pair_node(t+1, k);
254 _edge_lengths[e] = 0.0;
261 // The edges from the source to the entrances, and from the exits to
264 for(int t = 0; t < _nb_time_steps; t++) {
265 for(int l = 0; l < _nb_locations; l++) {
266 if(t > 0 && entrances[l]) {
267 node_from[e] = source;
268 node_to[e] = early_pair_node(t, l);
269 _edge_lengths[e] = 0.0;
272 if(t < _nb_time_steps - 1 && exits[l]) {
273 node_from[e] = late_pair_node(t, l);
275 _edge_lengths[e] = 0.0;
281 // We are done, build the graph
283 _graph = new MTPGraph(nb_vertices, nb_edges,
291 void MTPTracker::print_graph_dot(ostream *os) {
293 for(int t = 0; t < _nb_time_steps; t++) {
294 for(int l = 0; l < _nb_locations; l++) {
295 _edge_lengths[e++] = - detection_scores[t][l];
298 _graph->print_dot(os);
301 void MTPTracker::track() {
305 for(int t = 0; t < _nb_time_steps; t++) {
306 for(int l = 0; l < _nb_locations; l++) {
307 _edge_lengths[e++] = - detection_scores[t][l];
311 _graph->find_best_paths(_edge_lengths);
312 _graph->retrieve_disjoint_paths();
315 for(int p = 0; p < _graph->nb_paths; p++) {
316 Path *path = _graph->paths[p];
317 cout << "PATH " << p << " [length " << path->nb_nodes << "] " << path->nodes[0];
318 for(int n = 1; n < path->nb_nodes; n++) {
319 cout << " -> " << path->nodes[n];
326 int MTPTracker::nb_trajectories() {
327 return _graph->nb_paths;
330 scalar_t MTPTracker::trajectory_score(int k) {
331 return -_graph->paths[k]->length;
334 int MTPTracker::trajectory_entrance_time(int k) {
335 return (_graph->paths[k]->nodes[1] - 1) / (2 * _nb_locations);
338 int MTPTracker::trajectory_duration(int k) {
339 return (_graph->paths[k]->nb_nodes - 2) / 2;
342 int MTPTracker::trajectory_location(int k, int time_from_entry) {
343 return (_graph->paths[k]->nodes[2 * time_from_entry + 1] - 1) % _nb_locations;