QUAK/ESR ThorCam interface

Note: Work in progress

This is a small Python service that runs on a Windows machine to which the ThorCam is attached to provide a bridge into the control system that has been realized on an OpenSource platform - it exposes an MQTT interface for configuration of camera settings and queue configuration as well as event signalling and allows to transfer images taken using SFTP.

Since the required .NET library to interface with the not so simple to handle closed source ThorCam library this application only runs on Windows.

Installation

pip install quakesrthorcam-tspspi

Configuration file

MQTT section

The MQTT section configures the broker, port, user and password of the MQTT broker. The basetopic is a topic string that gets prepended to every message and to every subscription.

Currently this module subscribes to the following topics:

• trigger will allow software triggering of the camera (currently not implemented)
• setrun sets the current run parameters. Those are a current runprefix which is a single string that gets prepended in front of every filename and an optional list of strings called runsuffixthat are used instead of numbering the frames in consecutive order on each hardware trigger.
• exposure/set allows one to pass a message containing an exposure_ms field to update the exposure. The camera interrupts streaming and triggering operation during changes.

The camera publishes:

• raw/stored whenever a new raw frame has been stored and uploaded to the configured servers. It contains a localfilename and a imagefilename. The local filename also includes the path on the camera server while the image filename is just the filename without any path by itself.

Camera section thorcam

• serial is able to specify the serial number of the camera that the service should bind to. In case no serial is specified the first available camera is used
• trigger is an dictionary that is able to configure the default trigger settings:
  • hardware can be true or false
  • count specifies the number of frames to capture after the trigger has triggered the camera. This has to be either 0 for continuous capture or an positive integer.
• exposure can be used to set the default exposure (in milliseconds)

Local file storage

• imagedir specifies the directory where images should be stored locally

Upload configuration (SFTP)

• rawframesftp is a list of hosts to which the camera server should upload captured raw frames. Each entry is a dictionary that contains:
  • host specifies the host to which the upload should be made
  • user specifies the SSH user
  • destpath is the path on the remote machine where the images should be stored
  • keyfile points to the SSH private key file that should be used for authentication

Example configuration file

{
	"mqtt" : {
		"broker" : "10.0.0.5",
		"port" : "1883",
		"user" : "YourMqttUser",

		"password" : "NONDISCLOSEDSECRETLONGSTRING",

		"basetopic" : "quakesr/experiment/camera/ebeam"


	},
	"thorcam" : {
		"trigger" : {
			"hardware" : true,
			"count" : 1
		},
		"exposure" : 80
	},
	"imagedir" : "c:\\temp\\",
	"rawframesftp" : [
		{
			"host" : "10.0.0.15",
			"user" : "camserv",
			"keyfile" : "c:\\users\\quak\\id_winselwolf",
			"destpath" : "/home/pi/measurements/data/images/"
		}
    ]
}

Dependencies

• paho-mqtt is the Eclipse Paho MQTT Python client that provides the interface to the MQTT broker (currently running on an RabbitMQ instance)
• thorcam is a wrapper around the .NET libraries supplied for the ThorCam service.
• paramiko is a pure Python SSHv2 implementation mainly used for file transfer in this application.
• Pillow is a python image library (PIL) clone that's used to encode the images.