The following pages deal with the Dragonfly Java application. It assumes that the reader already had a basic experience with Dragonfly, by experiencing one of the 3 Dragonfly Demo Applications listed inside the left sidebar.

In order to use the Dragonfly Java application, you have to ensure that some requirements are met:

1 – Accuware account

The user needs to have valid set of Accuware credentials (username, password) and a SiteID in order to run the Dragonfly engine. To get new set of credentials and a SiteID, please open a Dragonfly free evaluation site filling the form at this link.

2 – Hardware

In order to run the Dragonfly engine with proper performances, the camera and the computing unit on which the Dragonfly Java application will run must meet some specifications.

2.1 – Computing unit

The hardware requirements to properly run the Dragonfly engine are these:

CPU when a MONOCULAR camera is usedmodern 64 bits CPU with at least 2 physical cores (e.g. Intel Core i3 or above)modern 64 bits CPU with at least 4 physical cores (e.g. AMD Ryzen 3, Intel Core i5-8250U or a generation below if it has 4 cores). WARNING: a processor with 2 cores and 4 threads is NOT considered as a 4 physical cores CPU
CPU when a STEREO camera is usedmodern 64 bits CPU with at least 4 physical cores (e.g. AMD Ryzen 3, Intel Core i5-8250U or a generation below if it has 4 cores). WARNING: a processor with 2 cores and 4 threads is NOT considered as a 4 physical cores CPU
RAM8 GB (for small venues - up to about 10.000 sqm)16 GB (for big venues - above 10.000 sqm)
OSTo run the Dragonfly engine you need Ubuntu 64 bits or macOS. We have tested it successfully on:
-Ubuntu 18.04 (aka Bionic Beaver)
-Ubuntu 16.04 (aka Xenial Xerus)
-macOS 10.13 (aka High Sierra)
Storageat least 4 GB of free space for the installation of the Dragonfly Java App + the additional space function of the size of the environments mapped
GPUnot used at present

Different OS: the Dragonfly Java App is meant to run on Linux and MacOs versions listed above:

  • If you want to try the Dragonfly Java App on other Ubuntu versions feel free to do it and to share your results with us using this form.
  • If you need the Dragonfly Java App to run on other OS, please contact us using this form and we can discuss a specific version for your OS.

2.2 – Camera

The camera used to perform the positioning must have:

  • Resolution: 640 x 480 at 60 Hz.
  • Focal length: constant.
  • Auto-focus: limited or disabled.
  • Field of view (FOV): from 70 degrees to 180 degrees (wide angles are preferable).

About FOV: a higher FOV allows the position to be more consistent and the device to move faster, but it decreases a little bit the accuracy of the position. That said, in our opinion, the loss in accuracy is negligible compared to the gain in positioning consistency. We would not recommend narrower FOV just with the goal of having an accuracy 1 cm better if it disallow the device to move at a proper speed and if the position is lost every 20 seconds because the camera doesn’t see enough features.

In case of 2 monocular cameras used in STEREO mode: both the monocular cameras must remain fixed on a rigid body and NEVER move after the calibration process done with our tool.

Examples of camera

  • MONOCULAR mode: we have obtained good results with the following USB cameras for field of view from 70 to 120 degrees:
  • STEREO mode:
    • two of the monocular cameras mentioned above work correctly (at about 15 cm from each other) if:
      • well calibrated.
      • they have a FOV between 70 and 120 degrees.
      • the device/vehicle is meant to look at obstacles more than 10 meters away.
    • built-in stereo camera most of the time won’t work inside big venues because the baseline is too small. A built-in stereo camera that works for small venues (an apartment for instance) is this one:

We can provide more references of our preferred camera models if required or we can give you a feedback about your preferred camera. Please send us the EXACT model of your camera using this form.

Camera calibration

In order to be used with the Dragonfly Java App, the camera must be calibrated. You have 2 options to do so:

  • Accuware Dragonfly Demonstration kit: if the Accuware Dragonfly Demonstration kit has been purchased (see below), the calibration of the camera has already been performed by the Accuware support team, and a JSON calibration file is already available inside the Dragonfly Java Application on board of the mini-PC.
  • Accuware Online Calibration Tool: if you have to calibrate your own camera, then you have to use the Accuware Camera Calibration tool available at this link. The tool outputs a JSON calibration file that have to be downloaded and placed inside the Dragonfly Java Application as explained inside the Usage page.

Monocular camera used at Accuware
Example of monocular camera used at Accuware (model: ELP USB camera 2.1 mm Lens 1080p HD)

3 – (OPTIONAL) Accuware Dragonfly DEMO kit

To facilitate the evaluation of the Dragonfly Java Application, it is possible to purchase from Accuware a ready-to-use demonstration kit including all the required software, hardware, camera and camera calibration.

Please contact us at using this form to place your order or to ask for more information


An example of the demonstration kit
An example of the Accuware Dragonfly Demonstration kit

NEXT STEP – How to setup the Dragonfly Java App