A Matlab interface for gPhoto to control camera/DSLR

This class can currently connect to a single DSLR camera via USB cable and GPhoto2. Then you can capture, change settings, etc

GPHOTO A class to control DSLR camera handled by gPhoto.

Usage

This class can currently connect to a single DSLR camera via USB cable and GPhoto2. Basically, type from Matlab:

• addpath /path/to/gphoto
• g = gphoto; % start the connection
• plot(g); % plot the GUI (with basic liveview)
• image(g); % trigger a capture/shoot
• get(g); % display all settings
• set(g, 'iso', 3200); % set the ISO
• set(g) % display a dialogue to change camera settings

You may as well specify a port used for the connection (for instance when using multiple cameras), e.g.:

• g=gphoto('usb:002,004');

You may as well try the simulator mode, which does not require gPhoto, nor a camera.

• g = gphoto('sim');

Then images are read from the gphoto/Images directory by default.

The Plot Window

The 'plot' method displays the current camera livewview, at a low refresh rate. The menus allow to:

• capture an image
• start/stop a continuous capture (timelapse)
• change settings
• change storage directory and liveview refresh rate
• display an X mark and focus quality indicator.

Time-lapse/continuous capture

The 'continuous' method and the similar menu item in the plot window allow to start/stop a periodic capture. The current camera settings are used. When the livewview refresh rate is smaller than the acquisition shutter time the images are capture as soon as possible, with minimal waitings.

• period(g, 0.5);
• continuous(g,'on'); % start time-lapse, capture asap (0.5 s).
• ...
• continuous(g, 'off');

When the refresh rate is larger than the shutter time, the next image is synchronized with the time-lapse.

• period(g, 15);
• continuous(g,'on'); % start time-lapse, capture every 15 seconds.

Trigger action on event

You may attach an action to a specific gPhoto event, e.g.:

• addlistener(g, 'captureStop', @(src,evt)disp('capture done.'))

Known actions are: captureStart, captureStop, idle and busy.

For instance, for astrophotography you may automatically annotate new images:

• install https://github.com/farhi/matlab-astrometry
• addlistener(g, 'captureStop', ... @(src,evt)astrometry(g.lastImageFile, 'scale-low', 0.5, 'scale-high',2,'autoplot'))

Methods

• about display a dialog box showing settings.
• cd change or get current directory where images are stored.
• char returns a character representation of the object
• continuous set/toggle continuous shooting (timelapse).
• delete close the Gphoto connection.
• disp display GPhoto object (details)
• display display GPhoto object (from command line)
• get get the camera configuration.
• grid set/toggle line markers and focus quality on plot.
• identify identify the connected camera
• image capture an image with current camera settings.
• ishold get the camera status (IDLE, BUSY).
• plot plot the camera interface, liveview and captured images.
• period set/get plot update periodicity, in seconds.
• preview capture a preview (small) image with current camera settings.
• set set a configuration value.
• start start the background gphoto control.
• stop stop the background gphoto control. Restart it with start.

Installation

You should first install gPhoto2. It exists as pre-built packages for Debian and RedHat type Linux systems, e.g.:

• sudo apt install gphoto2

Then, extract the project archive, which should contain a @gphoto directory. Then, add its path into Matlab:

addpath /path/to/matlab-gphoto

Connect your camera to the computer using e.g. a USB cable.

(c) E. Farhi, GPL2, 2019. https://gitlab.com/astrophotography/matlab-gphoto/