The limaCameras package¶

Introduction¶

The limaCameras package provides a mean for controlling cameras supported by LImA [1], for example Basler cameras.

LimaDevice expected parameters¶

Some LImA parameters are already available in the LimaDevice base class:

Camera Type, read-only
Camera Model, read-only
Sensor Width [pixel], read-only
Sensor Height [pixel], read-only
Image Depth [bytes], read-only
Trigger Mode
Exposure Time [ms]
Latency Time [ms]: the latency time between two successive exposures
Number of Frames: the number of frames to be acquired (0 means unlimited)
Image Rotation [degrees]
Image Flip (X and Y)
Image Binning (X and Y)
ROI (X, Y, Width and Height)

More parameters are available in the derived devices.

Deployment Guidelines¶

limaCameras will automatically install its dependency LImA.

In order to have the receiving thread executed with real time priority, the line

username rtprio 99

shall be added to the file /etc/security/limits.conf on the control server (may differ depending on the Linux distribution).

The MTU on the network interface used for the camera shall be set - when possible - to 9000, also known as “jumbo frames”.

For debugging purposes it can be useful to have tshark installed on the control server, and xctrl user added to the wireshark group.

The control server should have a 10 GbE network interface for sending images to the DAQ, and possibly one for the GUI server.

Please also check the camera specific configuration section, e.g. Basler’s Camera Setup.

Expert Contact¶

Andrea Parenti <andrea.parenti@xfel.eu>

How to create a new camera device in limaCameras¶

After checking-out limaCameras and its dependencies, as specified in the DEPENDS file, you can add your a new camera device in src/limaCameras, named for example MyLimaCamera.

Do not forget to add it to setup.py, in the entry_points section. This is needed to have it loaded by the Karabo python server.

Once you have done it, you can edit the source file (see MyLimaCamera.py file Section).

MyLimaCamera.py file¶

This method is abstract in LimaDevice and must therefore be defined in MyLimaCamera:

initializeCamera is the function where the Camera and HwInterface objects have to be initialized.

There are also two user’s hooks in the LimaDevice class, which do nothing by default but can be overwritten in the derived class:

pollCameraSpecific is called regularly, and can be used to read parameters from the camera and set them in the MyLimaCamera device.
reconfigureCameraSpecific is called upon reconfiguration of the device, and can be used to set camera specific parameters.

This method is defined in the base class but can be redefined in MyLimaCamera to do more specific checks:

isConnected shall return True if camera is connected.

This is for example the code for a camera using the Simulator plugin (Lima.Simulator subpackage):

#!/usr/bin/env python

#############################################################################
# Author: <andrea.parenti@xfel.eu>
# Created on Jul 21, 2017
# Copyright (C) European XFEL GmbH Hamburg. All rights reserved.
#############################################################################

from karabo.bound import (
    KARABO_CLASSINFO, PythonDevice
)

from .lima_device import LimaDevice

import Lima.Simulator

@KARABO_CLASSINFO("MyLimaCamera", "2.1")
class MyLimaCamera(LimaDevice, PythonDevice):
    def __init__(self, configuration):
        # always call PythonDevice constructor first!
        super(MyLimaCamera,self).__init__(configuration)

    @staticmethod
    def expectedParameters(expected):
        # Simulated camera does not have any additional parameters
        pass

    def initializeCamera(self):
        self.log.INFO("Initialize Simulated camera")

        # Creates the camera object (Simulator)
        self.camera = Lima.Simulator.Camera()
        # Creates the HwInterface
        self.interface = Lima.Simulator.Interface(self.camera)

Footnotes

[1]	Lima ( Library for Image Acquisition) is a project for the unified control of 2D detectors.