openflexure-microscope-server/openflexure_microscope/api/default_extensions/picamera_autocalibrate/extension.py
2020-05-12 14:29:11 +01:00

133 lines
4.2 KiB
Python

from labthings.server.view import View
from labthings.server.find import find_component
from labthings.server.extensions import BaseExtension
from labthings.server.decorators import ThingAction
from flask import abort
from contextlib import contextmanager
import logging
# Type hinting
from typing import Tuple
from .recalibrate_utils import (
recalibrate_camera,
auto_expose_and_freeze_settings,
flat_lens_shading_table,
)
@contextmanager
def pause_stream(scamera, resolution: Tuple[int, int] = None):
"""This context manager locks a streaming camera, and pauses the stream.
The stream is re-enabled, with the original resolution, once the with
block has finished.
"""
with scamera.lock:
assert (
not scamera.record_active
), "We can't pause the camera's video stream while a recording is in progress."
streaming = scamera.stream_active
old_resolution = scamera.camera.resolution
if streaming:
logging.info("Stopping stream in pause_stream context manager")
scamera.stop_stream_recording(resolution=resolution)
try:
yield scamera
finally:
scamera.camera.resolution = old_resolution
if streaming:
logging.info("Restarting stream in pause_stream context manager")
scamera.start_stream_recording()
def recalibrate(microscope):
"""Reset the camera's settings.
This generates new gains, exposure time, and lens shading
table such that the background is as uniform as possible
with a gray level of 230. It takes a little while to run.
"""
with pause_stream(microscope.camera) as scamera:
auto_expose_and_freeze_settings(
scamera.camera
) # scamera.camera is the PiCamera object
recalibrate_camera(scamera.camera)
microscope.save_settings()
@ThingAction
class RecalibrateView(View):
def post(self):
microscope = find_component("org.openflexure.microscope")
if not microscope:
abort(503, "No microscope connected. Unable to recalibrate.")
logging.info("Starting microscope recalibration...")
return recalibrate(microscope)
@ThingAction
class FlattenLSTView(View):
def post(self):
microscope = find_component("org.openflexure.microscope")
if not microscope:
abort(
503,
"No microscope connected. Unable to flatten the lens shading table.",
)
try:
with pause_stream(microscope.camera) as scamera:
flat_lst = flat_lens_shading_table(scamera.camera)
scamera.camera.lens_shading_table = flat_lst
microscope.save_settings()
except:
logging.exception("Error flattening the lens shading table.")
abort(
503,
"Couldn't flatten the lens shading table - do you have the forked PiCamera library installed?",
)
@ThingAction
class DeleteLSTView(View):
def post(self):
microscope = find_component("org.openflexure.microscope")
if not microscope:
abort(
503,
"No microscope connected. Unable to flatten the lens shading table.",
)
try:
with pause_stream(microscope.camera) as scamera:
scamera.camera.lens_shading_table = None
microscope.save_settings()
except:
logging.exception("Error deleting the lens shading table.")
abort(
503,
"Couldn't flatten the lens shading table - do you have the forked PiCamera library installed?",
)
lst_extension_v2 = BaseExtension(
"org.openflexure.calibration.picamera",
version="2.0.0-beta.1",
description="Routines to perform flat-field correction on the camera.",
)
lst_extension_v2.add_method(
recalibrate, "org.openflexure.calibration.picamera.recalibrate"
)
lst_extension_v2.add_view(RecalibrateView, "/recalibrate", endpoint="recalibrate")
lst_extension_v2.add_view(FlattenLSTView, "/flatten_lens_shading_table", endpoint="flatten_lens_shading_table")
lst_extension_v2.add_view(DeleteLSTView, "/delete_lens_shading_table", endpoint="delete_lens_shading_table")