1 files changed, 54 insertions, 0 deletions
diff --git a/pywalt/pywalt/screen_stats.py b/pywalt/pywalt/screen_stats.py
new file mode 100644
index 0000000..1930e6d
--- /dev/null
+++ b/pywalt/pywalt/screen_stats.py
@@ -0,0 +1,54 @@
+import numpy
+
+
+def screen_stats(blinker_file_name, sensor_file_name):
+
+    sensor_data = numpy.loadtxt(sensor_file_name)
+    blinker_data = numpy.loadtxt(blinker_file_name)
+
+    # Convert all times to milliseconds
+    t_sensor = sensor_data[:, 0] * 1e3
+    t_vsync = blinker_data / 1e3
+
+    # Throw away any sensor timestamps earlier than the first blink
+    # this may happen if the operator attached the sensor after
+    # running the command. But this should be avoided.
+    skip_sensor = sum(t_sensor < t_vsync[0])
+    if(skip_sensor):
+        t_sensor = t_sensor[skip_sensor:]
+        print('Skipped first %d readings from the sensor' % skip_sensor)
+
+    # Get only the common size and skip the first blink, it's often weird.
+    length = min(len(t_sensor), len(t_vsync))
+    t_sensor = t_sensor[1:length]
+    t_vsync = t_vsync[1:length]
+
+    # Shift time so that first time point is 0
+    t0 = min(t_vsync)
+    t_sensor = t_sensor - t0
+    t_vsync = t_vsync - t0
+
+    dt = t_sensor - t_vsync
+
+    # Look at even and odd transitions separately - black <-> white.
+    dt_even = dt[0::2]
+    dt_odd = dt[1::2]
+
+    print('')
+    print('dt = array([' + ', '.join('%0.2f' % x for x in dt) + '])')
+    print('')
+    print('Screen response times [ms]')
+    print('Even: median %0.1f ms, stdev %0.2f ms' %
+          (numpy.median(dt_even), numpy.std(dt_even)))
+    print('Odd:  median %0.1f ms, stdev %0.2f ms' %
+          (numpy.median(dt_odd), numpy.std(dt_odd)))
+
+
+# Debug & test
+if __name__ == '__main__':
+
+    fname = '/tmp/WALT_2016_06_22__1739_21_'
+    blinker_file_name = fname + 'evtest.log'
+    sensor_file_name = fname + 'laser.log'
+
+    screen_stats(blinker_file_name, sensor_file_name)