def _measure_tilt(self, tracker, mirror):
"""Establish the input face normal of a tilted mirror."""
if mirror is None:
raise AlignmentError('Mirror argument must be provided.')
else:
print 'Measuring mirror tilt.'
# FIXME: The mirror should reliably place where the CCD cannot
# see the main reflection.
mirror.position(self.beams[0].intercept[0]-50, wait=True)
tracker.power_index = 1
#TODO: Catch errors and remind user to reset CCD settings.
raw_input("Set CCD shutter to >1ms with gain 1. Press Enter when ready.")
self.front_reflections = []
start_point = [tracker.axes[0].limits.upper,
self.beams[0].last_sample()[1],
tracker.axes[2].limits.lower]
expose_single_beam(
tracker.devices['driver'], 0, self.beam_count())
self.front_reflections.append(
tracker.find_beam_trajectory(
start_point, -1, 1, z_samples=25))
self.mirror_normal = optics.reflection_normal(
self.front_reflections[0].direction, -self.beams[0].direction)
tracker.power_index = None
raw_input("Set CCD shutter to default setting 0.216ms with gain 1. Press Enter when ready.")
def sample_position(self, mirror_x, start_point=None,
x_scan_direction=1):
"""Returns the reflected beam trajectories with the mirror at the given
mirror stage position.
Takes the optional keyword arguments.
start_point (None):
Start the scan at a position given by the coordinates in the form
[x, y, z]. By default, the start point is determined from the
stage limits.
x_scan_direction (1):
The direction to scan for the beam in x.
"""
self.mirror.position(mirror_x, wait=True)
tracked_beams = []
if start_point is None:
start_point, x_scan_direction = self._find_start_point(mirror_x)
for beam_index, in_range in enumerate(
tuple(self._beams_in_range(mirror_x))):
if not in_range:
print('Skipping Beam {}'.format(beam_index))
tracked_beams.append(None)
continue
expose_single_beam(self.tracker.devices['driver'],
beam_index,
self.alignment.beam_count())
time.sleep(0.25)
tracked_beams.append(
self.tracker.find_beam_trajectory(
start_point,
x_scan_direction,
scan_direction_z=(1 if start_point[2] < 0 else -1),
measure_power=True
))
if tracked_beams[-1] is None:
print('Failed to find beam {}.'.format(beam_index))
start_point = self.tracker.position().array()
self.data.append(
DataPoint([self.mirror.position().value, self.input_y, 0],
tracked_beams))
return self.data[-1]
def align(self, tracker, home=False, tilted=False, mirror=None):
"""Establishes the alignment between the given tracker and the beams.
Takes an optional keyword argument
home (False): Recalibrates the rotation stage to it's home switch.
"""
if tilted and mirror is None:
raise AlignmentError(
'Mirror axis must given as keyword argument to measure tilt.')
print 'Measuring tracker alignment. This will take some time.'
self.beams = []
self.displacements = []
tracker.devices['r_stage'].power_on()
if home:
tracker.devices['r_stage'].go_to_home(wait=True)
tracker.rotate(180, wait=True)
start_point = [tracker.axes[0].limits.upper,
tracker.axes[1].limits.upper - 8,
tracker.axes[2].limits.upper]
z_direction = -1
for beam_index in self.beam_indexes():
if tilted and beam_index > 0:
self.beams.append(self.beams[0])
continue
expose_single_beam(
tracker.devices['driver'], beam_index, self.beam_count())
self.beams.append(
tracker.find_beam_trajectory(
start_point, -1, z_direction, z_samples=25,
measure_power=True))
start_point = self.beams[-1].last_sample() + [-180, 0, 0]
z_direction = -1 * z_direction
self.displacements.append(
self.beams[beam_index].intercept - self.beams[0].intercept)
tracker.rotate(0, wait=True)
if tilted:
self._measure_tilt(tracker, mirror)
self.date = datetime.datetime.now().isoformat()