openflexure_microscope_server.things.camera.BaseCamera

Open hardware connection when the Thing context manager is opened.

Close hardware connection when the Thing context manager is closed.

Initialise the base camera, this creates the background detectors.

This must be run by all child camera classes.

To add a new background detector to the server it must be added to the dictionary in this function. Configuration will be added at a later date.

The name of the active background selector.

Validate and set background_detector_name.

Acquire one image from the camera.

This will use the internal capture image functionally of _capture_image of the specific camera being used.

Capture an image and save it to disk.

This is not an action as it exposes a direct path for saving

Acquire one image from the camera and return as an array.

Acquire one image from the camera, downsample, and return as an array.

• The array is downsampled by the thing property downsampled_array_factor.
• The default capture array arguments are used.

This method provides the interface expected by the camera_stage_mapping.

Capture an image to memory. This can be saved later with save_from_memory.

Note that only one image is held in memory so this will overwrite any image in memory.

Change the mode the camera is streaming in.

When creating a subclass. Subclass the method _start_streaming rather than this method.

Clear all images in memory.

Discard frames so that the next frame captured is fresh.

Acquire one image from the preview stream and return as an array.

It works like grab_jpeg but reliably handles broken streams. Prefer using this method over directly grabbing the frame and converting to a numpy array via PIL.

This differs from capture_as_array in that it does not pause the MJPEG preview stream.

Acquire one image from the preview stream and return as blob of JPEG data.

Note: in rare cases the JPEG stream may be broken. This can cause an OS error when loading the image. If loading with PIL, as long as the header data is complete, this error will not be raised until the data is accessed. Consider using grab_jpeg_as_array instead.

This differs from capture in that it does not pause the MJPEG preview stream. Instead, we simply return the next frame from that stream (either "main" for the preview stream, or "lores" for the low resolution preview). No metadata is returned.

Acquire one image from the preview stream and return its size.

Label the current image as either background or sample.

Kill the streams now as the server is shutting down.

This is called when uvicorn gets the a shutdown signal. As this is called from the event loop it cannot interact with the our ThingProperties or run self.mjpeg_stream.stop() as the portal cannot be called from this loop.

Instead we just set the _streaming value to False. This stops the async frame generator when the next frame notifies.

Record MJPEG stream framerate statistics.

Save an image that has been captured to memory.

Note this is not exposed as an action as it allows arbitrary paths on disk to be written to.

Grab an image, and use its statistics to set the background.

This should be run when the microscope is looking at an empty region, and will calculate the mean and standard deviation of the pixel values in the LUV colourspace. These values will then be used to compare future images to the distribution, to determine if each pixel is foreground or background.

Sleep for the settling time, ready to provide a fresh frame.

This function will sleep for the given time, and clear the buffer after sleeping. As such, the next frame captured from the camera after running this function will always be captured after settling.

This method provides the interface expected by the camera_stage_mapping.

Return a snapshot from the microscope.