def _acq_wait_data(self, timeout=0):
"""
Block until a data is received, or a stop message.
Note: it expects that the acquisition is running.
timeout (0<=float): how long to wait to check (use 0 to not wait)
return (bool): True if needs to stop, False if data is ready
raise TerminationRequested: if a terminate message was received
"""
tend = time.time() + timeout
while True:
left = max(0, tend - time.time())
try:
msg = self._get_acq_msg(timeout=left)
except queue.Empty:
raise TimeoutError("No data message received within %s s" % (timeout,))
if msg == GEN_DATA:
return False
elif msg == GEN_TERM:
raise TerminationRequested()
elif msg == GEN_STOP:
return True
elif isinstance(msg, float): # trigger
# received trigger too early => store it for later
self._old_triggers.insert(0, msg)
else: # Anything else shouldn't really happen
logging.warning("Skipped message %s as acquisition is waiting for trigger", msg)
def _waitTemperatureReached(self, comp, timeout=None):
"""
Wait until the current temperature of the component has reached the
target temperature (within some margin).
comp (Component)
timeout (0<float or None): maximum time to wait (in s)
raises:
TimeoutError: if time-out reached
"""
tstart = time.time()
while timeout is None or time.time() < tstart + timeout:
# TODO: adjust the timeout depending on whether the temperature
# gets closer to the target over time or not.
ttemp = comp.targetTemperature.value
atemp = comp.temperature.value
if atemp < ttemp + TEMP_EPSILON:
return
else:
logging.debug(
u"Waiting for temperature to reach %g °C (currently at %g °C)",
ttemp, atemp)
time.sleep(1)
raise TimeoutError("Target temperature (%g C) not reached after %g s" %
(comp.targetTemperature.value, timeout))
def _doWholeAcquisition(self, electron_coordinates, scale):
"""
Perform acquisition with one optical image for all the spots.
It's faster, but it's harder to separate the spots.
"""
escan = self.escan
ccd = self.ccd
detector = self.detector
dwell_time = self.dwell_time
# order matters
escan.scale.value = scale
escan.resolution.value = self.repetitions
escan.translation.value = (0, 0)
# Scan at least 10 times, to avoids CCD/SEM synchronization problems
sem_dt = escan.dwellTime.clip(dwell_time / 10)
escan.dwellTime.value = sem_dt
# For safety, ensure the exposure time is at least twice the time for a whole scan
if dwell_time < 2 * sem_dt:
dwell_time = 2 * sem_dt
logging.info(
"Increasing dwell time to %g s to avoid synchronization problems",
dwell_time)
# CCD setup
ccd.binning.value = (1, 1)
ccd.resolution.value = ccd.shape[0:2]
et = numpy.prod(self.repetitions) * dwell_time
ccd.exposureTime.value = et # s
readout = numpy.prod(ccd.resolution.value) / ccd.readoutRate.value
tot_time = et + readout + 0.05
try:
if self._acq_state == CANCELLED:
raise CancelledError()
if self.bgsub:
self.bg_image = ccd.data.get(asap=False)
detector.data.subscribe(self._discard_data)
self._min_acq_time = time.time()
ccd.data.subscribe(self._onCCDImage)
logging.debug("Scanning spot grid...")
# Wait for CCD to capture the image
if not self._ccd_done.wait(2 * tot_time + 4):
raise TimeoutError("Acquisition of CCD timed out")
with self._acq_lock:
if self._acq_state == CANCELLED:
raise CancelledError()
logging.debug("Scan done.")
self._acq_state = FINISHED
finally:
detector.data.unsubscribe(self._discard_data)
ccd.data.unsubscribe(self._onCCDImage)
return self._optical_image, electron_coordinates, scale
def _DoAcquisition(future, escan, ccd, detector, light):
_sem_done.clear()
try:
if future._acq_state == CANCELLED:
raise CancelledError()
logging.debug("Acquiring CCD images...")
# Turn on light for CCD acquisition
intensities = [1, 0, 0, 0, 0, 0, 0]
light.power.value = [
ints * pw for ints, pw in zip(intensities, light.power.range[1])
]
optical_image_1 = ccd.data.get()
intensities = [0, 1, 0, 0, 0, 0, 0]
light.power.value = [
ints * pw for ints, pw in zip(intensities, light.power.range[1])
]
optical_image_2 = ccd.data.get()
intensities = [0, 0, 1, 0, 0, 0, 0]
light.power.value = [
ints * pw for ints, pw in zip(intensities, light.power.range[1])
]
optical_image_3 = ccd.data.get()
with _acq_lock:
if future._acq_state == CANCELLED:
raise CancelledError()
logging.debug("Acquisition done.")
future._acq_state = FINISHED
# Turn off light for CCD acquisition
light.power.value = light.power.range[0]
logging.debug("Acquiring SEM image...")
detector.data.subscribe(_ssOnSEMImage)
# Wait for SEM to capture the image
if not _sem_done.wait(2 * numpy.prod(escan.resolution.value) *
escan.dwellTime.value + 4):
raise TimeoutError("Acquisition of SEM timed out")
detector.data.unsubscribe(_ssOnSEMImage)
finally:
detector.data.unsubscribe(_ssOnSEMImage)
return optical_image_1, optical_image_2, optical_image_3, detector.data._electron_image
def acquire_roa(self, dataflow):
"""
Acquire the single field images that resemble the region of acquisition (ROA, megafield image).
:param dataflow: (model.DataFlow) The dataflow on the detector.
"""
total_field_time = self._detector.frameDuration.value + 1.5 # there is about 1.5 seconds overhead per field
# The first field is acquired twice, so the timeout must be at least twice the total field time.
# Use 5 times the total field time to have a wide margin.
timeout = 5 * total_field_time + 2
# Acquire all single field images, which are automatically offloaded to the external storage.
for field_idx in self._roa.field_indices:
# Reset the event that waits for the image being received (puts flag to false).
self._data_received.clear()
self.field_idx = field_idx
logging.debug("Acquiring field with index: %s", field_idx)
self.move_stage_to_next_tile(
) # move stage to next field image position
self.correct_beam_shift(
) # correct the shift of the beams caused by the parasitic magnetic field.
dataflow.next(field_idx) # acquire the next field image.
# Wait until single field image data has been received (image_received sets flag to True).
if not self._data_received.wait(timeout):
# TODO here we often timeout when actually just the offload queue is full
# need to handle offload queue error differently to just wait a bit instead of timing out
# -> check if finish megafield is called in finally when hitting here
raise TimeoutError("Timeout while waiting for field image.")
self._fields_remaining.discard(field_idx)
# In case the acquisition was cancelled by a client, before the future returned, raise cancellation error.
# Note: The acquisition of the current single field image (tile) is still finished though.
if self._cancelled:
raise CancelledError()
# Update the time left for the acquisition.
expected_time = len(self._fields_remaining) * total_field_time
self._future.set_progress(start=time.time(),
end=time.time() + expected_time)
logging.debug("Successfully acquired all fields of ROA.")
def acquire_roa(self, dataflow):
"""
Acquire the single field images that resemble the region of acquisition (ROA, megafield image).
:param dataflow: (model.DataFlow) The dataflow on the detector.
:return: (list of DataArrays): A list of the raw image data. Each data array (entire field, thumbnail,
or zero array) represents one single field image within the ROA (megafield).
"""
total_field_time = self._detector.frameDuration.value
timeout = total_field_time + 5 # TODO what margin should be used?
# Acquire all single field images, which are automatically offloaded to the external storage.
for field_idx in self._roa.field_indices:
# Reset the event that waits for the image being received (puts flag to false).
self._data_received.clear()
self.field_idx = field_idx
logging.debug("Acquiring field with index: %s", field_idx)
self.move_stage_to_next_tile(
) # move stage to next field image position
if field_idx != (0, 0):
self.correct_beam_shift(
) # correct the shift of the beams caused by the parasitic magnetic field.
dataflow.next(field_idx) # acquire the next field image.
# Wait until single field image data has been received (image_received sets flag to True).
if not self._data_received.wait(timeout):
# TODO here we often timeout when actually just the offload queue is full
# need to handle offload queue error differently to just wait a bit instead of timing out
# -> check if finish megafield is called in finally when hitting here
raise TimeoutError("Timeout while waiting for field image.")
self._fields_remaining.discard(field_idx)
# In case the acquisition was cancelled by a client, before the future returned, raise cancellation error.
# Note: The acquisition of the current single field image (tile) is still finished though.
if self._cancelled:
raise CancelledError()
# Update the time left for the acquisition.
expected_time = len(self._fields_remaining) * total_field_time
self._future.set_progress(end=time.time() + expected_time)
return self.megafield
def move_stage_to_next_tile(self):
"""Move the stage to the next tile (field image) position."""
pos_hor, pos_vert = self.get_abs_stage_movement(
) # get the absolute position for the new tile
f = self._stage.moveAbs({
'x': pos_hor,
'y': pos_vert
}) # move the stage
timeout = 100
try:
f.result(timeout=timeout) # don't wait forever
logging.debug("Moved to stage position %s" %
(self._stage.position.value, ))
except TimeoutError:
raise TimeoutError(
"Stage movement to position (%s, %s) timed out after %s s." %
(timeout, pos_hor, pos_vert))
def _changePressure(self, p):
"""
Synchronous change of the pressure
p (float): target pressure
"""
if p["pressure"] == PRESSURE_VENTED:
self.parent._device.VacVent()
else:
self.parent._device.VacPump()
start = time.time()
while not self.GetStatus() == 0:
if (time.time() - start) >= VACUUM_TIMEOUT:
raise TimeoutError("Vacuum action timed out")
# Update chamber pressure until pumping/venting process is done
self._updatePosition()
self._position = p
self._updatePosition()
def _acq_wait_data(self, exp_tend, timeout=0):
"""
Block until a data is received, or a stop message.
Note: it expects that the acquisition is running.
exp_tend (float): expected time the acquisition message is received
timeout (0<=float): how long to wait to check (use 0 to not wait)
return (bool): True if needs to stop, False if data is ready
raise TerminationRequested: if a terminate message was received
"""
now = time.time()
ttimeout = now + timeout
while now <= ttimeout:
twait = max(1e-3, (exp_tend - now) / 2)
logging.debug("Waiting for %g s", twait)
if self._acq_should_stop(twait):
return True
# Is the data ready?
if self.CTCStatus():
logging.debug("Acq complete")
return False
now = time.time()
raise TimeoutError("Acquisition timeout after %g s")
def _doSpotAcquisition(self, electron_coordinates, scale):
"""
Perform acquisition spot per spot.
Slow, but works even if SEM FoV is small
"""
escan = self.escan
ccd = self.ccd
detector = self.detector
dwell_time = self.dwell_time
escan.scale.value = (1, 1)
escan.resolution.value = (1, 1)
# Set dt large enough so we unsubscribe before we even get an SEM
# image (just to discard it) and start a second scan which would
# cost in time.
sem_dt = 2 * dwell_time
escan.dwellTime.value = escan.dwellTime.clip(sem_dt)
# CCD setup
sem_shape = escan.shape[0:2]
# sem ROI is ltrb
sem_roi = (electron_coordinates[0][0] / sem_shape[0] + 0.5,
electron_coordinates[0][1] / sem_shape[1] + 0.5,
electron_coordinates[-1][0] / sem_shape[0] + 0.5,
electron_coordinates[-1][1] / sem_shape[1] + 0.5)
ccd_roi = self.sem_roi_to_ccd(sem_roi)
self.configure_ccd(ccd_roi)
if self.bgsub:
_set_blanker(self.escan, True)
self.bg_image = ccd.data.get(asap=False)
_set_blanker(self.escan, False)
et = dwell_time
ccd.exposureTime.value = et # s
readout = numpy.prod(ccd.resolution.value) / ccd.readoutRate.value
tot_time = et + readout + 0.05
logging.debug("Scanning spot grid with image per spot procedure...")
self._spot_images = []
for spot in electron_coordinates:
self._ccd_done.clear()
escan.translation.value = spot
logging.debug("Scanning spot %s", escan.translation.value)
try:
if self._acq_state == CANCELLED:
raise CancelledError()
detector.data.subscribe(self._discard_data)
ccd.data.subscribe(self._onSpotImage)
# Wait for CCD to capture the image
if not self._ccd_done.wait(2 * tot_time + 4):
raise TimeoutError("Acquisition of CCD timed out")
finally:
detector.data.unsubscribe(self._discard_data)
ccd.data.unsubscribe(self._onSpotImage)
with self._acq_lock:
if self._acq_state == CANCELLED:
raise CancelledError()
logging.debug("Scan done.")
self._acq_state = FINISHED
return self._spot_images, electron_coordinates, scale
