PST SDK  6.0.0.0-272350a
reference.py
1 """Reference example of the PST SDK
2 
3 This example shows how to use the PST SDK to adjust the PST Tracker reference system.
4 The reference system defines the Cartesian coordinate system in which tracking results
5 are reported. The example shows how to set the reference system by supplying a 4x4
6 homogeneous transformation matrix. It also shows how to check if the reference system
7 was set successfully.
8 
9 Copyright PS-Tech B.V. All Rights Reserved.
10 """
11 import context
12 import time
13 import sys
14 import pstech.pstsdk.tracker as pst
15 import pstech.pstsdk.errors as psterrors
16 
17 #global variables for example
18 running = True
19 max_samples = 1000
20 samples = 0
21 
22 """Helper function for printing """
23 def print_matrix(matrix):
24  for y in range(4):
25  for x in range(4):
26  print(str(matrix[x + y * 4]), end="\t")
27  print("")
28  print("\n")
29 
30 # Control variable for main loop
31 running = True
32 
33 # Number of data points to grab before application termination
34 max_samples = 100
35 
36 # Global number of samples
37 samples = 0
38 
39 """Implementation of the pst.Listener class to receive tracking data and mode changes."""
40 class MyListener(pst.Listener):
41 
42  """Implementation of a tracker data callback function
43 
44  Implementation of a tracker data callback function. The on_tracker_data
45  function receives the data as soon as it becomes available.
46 
47  Args:
48  tracker_data: Object containing tracking information retrieved from tracker
49  status_message: Status message reported by the tracker.
50 
51  See Also:
52  pstech.pstdk.trackerdata.TrackerData
53  pstech.pstsdk.errors.EStatusMessage
54  """
55  def on_tracker_data(self, tracker_data, status_message):
56  global samples
57  global running
58 
59  if samples >= max_samples:
60  running = False
61 
62  samples += 1
63  # Do something here with the received data
64 
65 """Helper function to register the exit handler with the application"""
66 def register_exit_handler():
67  if sys.platform.startswith("linux"):
68  import signal
69  signal.signal(signal.SIGTERM, exit_handler)
70  signal.signal(signal.SIGHUP, exit_handler)
71  signal.signal(signal.SIGQUIT, exit_handler)
72  signal.signal(signal.SIGINT, exit_handler)
73  elif sys.platform.startswith("win"):
74  import win32api
75  win32api.SetConsoleCtrlHandler(exit_handler, True)
76 
77 """Implement the exit handler to shut-down the PST Tracker connection on application termination."""
78 def exit_handler(*args):
79  global running
80  pst.Tracker.shutdown()
81  running = False
82  return True
83 
84 def main():
85  if(len(sys.argv) < 2):
86  print("\nConfiguration Error: A camera configuration file needs to be specified. This file can be found in the Redist folder of your installation. "
87  "See the documentation of the Python bindings for more information.")
88  exit(0)
89 
90  # Register exit_handler for proper shutdown
91  register_exit_handler()
92 
93  try:
94  # Use Context Manager to prevent improper Tracker shutdown on errors.
95  # Create an instance of the Tracker object using the default configuration path and file names.
96  with pst.Tracker("", "","", sys.argv[1]) as tracker:
97  # Print version number of the tracker server being used.
98  print("Running PST Server version " + tracker.get_version_info())
99 
100  # Create listener with callback functions for data and/or mode updates.
101  listener = MyListener()
102 
103  # Register the listener object to the tracker server.
104  tracker.add_tracker_listener(listener)
105 
106  # Start the tracker server.
107  tracker.start()
108 
109  # Perform a system check to see if the tracker server is running OK and print the result.
110  print("System check: " + str(tracker.system_check()))
111 
112  # Set the frame rate to 30 Hz.
113  tracker.set_framerate(30)
114 
115  # Print the new frame rate to see if it was set correctly. Note that for PST HD and Pico
116  # trackers the frame rate actually being set can differ from the value provided to Tracker.set_framerate().
117  print("Frame rate set to: " + str(tracker.get_framerate()))
118  print("***************************\n")
119 
120  # Get the transformation matrix for the current reference system.
121  print("Current reference system transformation matrix:")
122  print_matrix(tracker.get_reference())
123 
124  # Define new reference system transformation matrix rotating the reference system by
125  # 90 degrees around the X-axis and 180 degrees around the Y-axis. Then translate the
126  # origin of the reference system by 0.1 m in the X direction, -0.5 m in the Y direction
127  # and 0.5 m in the Z direction.
128  reference = [-1.0, 0.0, 0.0, 0.1,
129  0.0, 0.0, 1.0,-0.5,
130  0.0, 1.0, 0.0, 0.5,
131  0.0, 0.0, 0.0, 1.0]
132 
133  tracker.set_reference(reference)
134  print("New reference system transformation matrix:")
135  print_matrix(tracker.get_reference())
136 
137 
138  # Trying to set the reference using a non-orthonormal transformation matrix (this should fail).
139  non_orthonormal_reference = [-1.0, 1.0, 0.0, 0.1,
140  0.0, 0.0,-1.0,-0.5,
141  0.0,-1.0, 0.0, 0.5,
142  0.0, 0.0, 0.0, 1.0
143  ]
144  try:
145  tracker.set_reference(non_orthonormal_reference)
146  print("Reference input incorrectly applied!")
147  except psterrors.TrackerError as err:
148  # This should fail because the supplied matrix is non-orthonormal
149  print("Reference input correctly ignored: %s" % err.message)
150  print("New reference system after applying non-orthonormal transformation:")
151  print_matrix(tracker.get_reference())
152 
153  # Adjust the reference system by applying a relative transformation. The new reference system will have
154  # the X-axis pointing outward from the tracker and the Y-axis parallel to the tracker front.
155  relative_reference = [ 0.0,-1.0, 0.0, 0.5,
156  1.0, 0.0, 0.0, 0.4,
157  0.0, 0.0, 1.0, 0.0,
158  0.0, 0.0, 0.0, 1.0
159  ]
160  tracker.set_reference(relative_reference, True)
161  print("New reference system after applying relative transformation:")
162  print_matrix(tracker.get_reference())
163  print("***************************\n")
164 
165  # Reset reference system to default (origin at 1 m from center of the PST Tracker,
166  # Z-axis pointing outward from the PST Tracker).
167  tracker.set_default_reference()
168  print("Reset default reference system:")
169  print_matrix(tracker.get_reference())
170 
171  while running:
172  time.sleep(0.1)
173 
174  except psterrors.TrackerError as err:
175  # Catch TrackerError and print error messages.
176  print(err.message)
177 
178 if __name__ == "__main__":
179  main()