Tag Archives: followme

UAVs for site tour recording – Part 1 – Theory

Thanks to UAVs there is a growing potential for the provision of high quality visualizations of sites from the air for public consumption; whether as part of the requirement of many archaeology companies as charities, as part of planning policies to interact with the public, or the growing importance of crowdfunding archaeological excavations (DigVentures) which require interaction with their backers. UAVs can provide a means of providing this sort of imagery as part of an overall recording strategy. This includes the recording of site tours which can provide details of a sites which can easily be disseminated to the public.

At its simplest the UAV can provide an aerial element to the video of the site tour by flying past or through elements of the site or flying past or hovering in front of the site tour guide.

The DJI Inspire 1 is one such aerial video platform which can be purchased with two remote controllers; one for controlling the UAV, while the other is used to control the camera gimbal. This allows a pilot to fly the UAV on a set path while someone experienced in film making has complete control of the camera.

DJI Inspire 1

DJI Inspire 1

Although the UAV can provide an excellent platform for aerial video recording as part of site tours, recently developed technologies can make this much more automated and provide a means for one person to both:

  1. The site tour guide.
  2. The UAV pilot recording the site tour.

There are two ways in which this can be done.

1. GPS ‘Follow Me’ technology

'Follow Me' technology (DroneDog using Pixhawk)

‘Follow Me’ technology (DroneDog using Pixhawk)

This functionality is available on many UAVs, including some of the DJI series and those using the open source PX4 and Pixhawk autopilot technologies.

With the PX4/Pixhawk systems the mode can be controlled from a number of base station software solutions including Tower, which can run on Android mobile devices such as smartphones.

The systems uses the GPS of the mobile device as a target for the UAV.

A number of cinematic controls for the UAV are available in the app:

  • Leash – UAV follows actor.
  • Lead – UAV leads actor pointing back at them.
  • Left/Right – UAV keeps pace with actor to the side.
  • Circle – UAV circles actor at specified radius.
'Follow Me' controls (3DR Tower)

‘Follow Me’ controls (3DR Tower)

The following parameters can also be set:

  • Altitude.
  • Radius.
3DR Tower - Altitude and Radius

3DR Tower – Altitude and Radius

The system also controls the camera gimbal, pointing the camera towards the GPS enabled device.

Together these controls can provide various aerial video elements useful for integration in a site tour video which can be controlled directly from the mobile device in the hand of the site tour guide.

2.Computer vision technologies

Computer Vision technologies are an important developing area in robotics and are beginning to be fitted to UAVs.

Some of these technologies use image recognition algorithms to match the subject matter between consecutive video frames allowing the UAV to follow a person or object even when it is rotating and so changing the way it appears.

They come in three forms:

A. Software

Currently in beta testing the Vertical Studio app (available on iOS and Android) uses existing camera hardware on the DJI Phantom 3 or Inspire to provide the imagery for the image recognition algorithms running in the app. A target is chosen in the app which then controls the flight of the UAV.

Vertical Studio App

Vertical Studio App

You can also draw walls in the app that designate no fly areas for the UAV.

Walls in the Vertical Studio App

Walls in the Vertical Studio App

B. Add-on technology

The second is an add-on technology that is fitted to an existing UAV, which connects to the autopilot and controls the flight of the UAV. In the case of the Percepto (funded on the Indiegogo crowdfunding website) the processing is done in a companion computer while the video is taken from an add-on camera, controls are then sent to the autopilot and gimbal to control the movement of them in relation to the subject matter.

Percepto Tracking

Percepto Tracking

Percepto Kit

Percepto Kit

C. Integrated technology

The third is an an integral part a newly built UAV, but is in effect a very similar technology to B.

This is the case with the soon to be released DJI Phantom 4, which is the first commercially available UAV with the technology integrated into it.

The app connects to a companion computer on the UAV which uses the imagery from the camera as a source for the computer vision algorithms. Once again the subject matter is selected in the app and the UAV will follow it.

Phantom 4 App

Phantom 4 App









The PlexiDrone is an Indiegogo drone project aimed at film makers and aerial photographers.

The system comes in two different configurations; the x4 has four rotors while the x8 has 8, four above and four below. As a result they have different flight characteristics.

  • Flight time – 25 mins x4, 20 mins x8
  • Speed – 37 mph x4, 42mph x8
  • Thrust – 2.35 kg x4, 4.1 kg x8

It’s other specifications include:

  • Follow me technology
  • Retractable landing gear allowing an unobstructed view below the drone enabling a 360˚ camera gimbal
  • SwarmTech allowing multiple drones to be controlled and film the same subject matter
  • Object avoidance using ultrasonic sensors which can sense up to 32 ft. (10 m)
  • The market version will include a bottom facing ultrasonic sensor which will help control altitude and lower the landing gear when required
  • It will also include a front-facing and bottom facing optical flow sensor helping with stability when indoors and without a GPS signal
  • The PlexiDrone allows modular payloads including:
    1. PlexiDrone 3D Gimbal which carries a GoPro
      PlexiCinema 3D Gimbal which carries mirror-less cinema-quality cameras like the Sony A5000, Sony RX100 III, and Lumix GM5
      Bubl 360˚ Camera
      Sony ActionCam
  • PlexiGCS control App on iOS, Android or Windows
  • Snap together construction fits into the PlexiPack or PlexiPack Mini custom made backpack
  • PlexiFPV Real-time video which simply snaps onto the PlexiDrone
  • The system will work with standard RC (Radio Control) controllers
  • 3-axis camera stabilisation

The PlexiDrone comes in a number of buying packages as a quadcopter and as an octocopter.

  • The Standard package comes without a gimbal for $699
  • The Pro package comes with a gimbal for $799
  • The Swarm Pro pack with 3 PlexiDrones and a PlexiHub to control them for $2,499
  • The 3D gimbal can be purchased for $159 which will carry a GoPro or other action camera
  • The PlexiCinema 3D gimbal can be purchased for $349
  • The PlexiFPV first person view system can be purchased for $215
  • The system can be upgraded to an octocopter for $199 by replacing the single rotor snap-on arms with dual ones

Due to the fact that the PlexiDrone is aimed at aerial photography rather than another discipline it is better suited to the recording of Cultural Heritage and Archaeology. As well as having a number of different photographic platforms available it also has technology such as follow me, obstacle avoidance, optical flow sensors and swarm capabilities which add to its potential for recording in different environments. Some of these technologies are only available on the much more expensive DJI Aspire 1.

The retractable landing gear allows for much more freedom of movement in the camera gimbal which can record 360˚ around the horizontal access and 180˚ in the vertical without any of the drone appearing in the photographs.

The snap together construction of the PlexiDrone allows for easy packing into a backpack style storage system which appears easily portable.

The fact that the system has easily interchangeable payloads allows for much more flexibility in recording than other systems. It can carry a GoPro like all of the other cheap drone systems, but can also carry heavier cameras with better optics and higher megapixels allowing greater quality recording and it can also carry the bubl 360˚ camera as well adding 360˚ recording to its abilities.

The swarm capabilities allows multiple drones to record the same subject from different directions, increasing the speed of recording and the amount recorded.

Using the swarm capability obviously adds significantly the cost.

Although it can carry more complex digital cameras it cannot carry the heavier high-spec digital SLR cameras.

Ghost Drone

The Ghost Drone is a wind and rain resistant Indiegogo project drone aimed at filmmakers, photographers, sports enthusiasts, travelers and adventurers, GoPro owners and first time and experienced drone pilots.

It is controlled by a smartphone app (either iOS or Android operating systems) where you can click on a map and the drone will go to that position; the map can be downloaded in advance. The app also has a number of one-click commands including take off, hover, return and land. Two sliding bars can be used to control the height and orientation of the drone; while another two control the camera gimbal with one tilting the camera up and down while the other pans it left and right. It’s micro control feature allows more precise movement of the drone over small distances. The Auto-Follow mode keeps the drone following the smart phone. If the drone exceeds 0.6 mile limit or the signal is lost it will return to its place of origin.

The app communicates with the drone via a G-box system, with the app communicating with the G-box via bluetooth while the G-box communicates with the drone via a wireless radio.

Other developments at higher Indiegogo targets include integration with a waterproof smartwatch and controlling the drone by tilting the smartphone, while obstacle avoidance will be available in future versions.

  • Up to 20 mins flight time with the gimbal
  • 10 mph (restricted) flight speed
  • Up to 0.6 miles control distance
  • Wind resistance up to 21 knot (11m/s)
  • iOS and Android apps
  • Propeller protectors

The Ghostdrone comes in 3 seperate versions, only two of which have a camera gimbal:

  • Ghost Basic (£430) – No camera gimbal.
  • Ghost Aerial (£550) – 2-axis gimbal designed for GoPro and similar cameras.
  • Ghost Aerial Plus (£559) – 2-axis gimbal and Ehang Sports camera.

An RC controller can be purchased for an extra $99. Another optional extra are prop guards to protect both the system and what is may be flying near, and photos on the site seem to suggest that the mini legs attached to them can be used to replace the main landing gear, this would allow a greater field of view.

The Ghost Drone is marketed as the easiest done to fly, and the flight controls within the app will certainly enable many autonmated movements with one button click.

The propellors of the system are pointing down rather than up (unlike other systems), this is believed to provide more stable flight.

The fact that the Ghost Drone is wind and rain resistant means that is can be used in conditions that would ground other systems.

As with other systems, the follow-me technology will allow the easy recording of video site tours.

The Ghost Drone comes with an SDK (Software Development Kit) which has already been used by one of the users to create voice interface which can be used to control the drone.

The Ghost Drone is limited to the abilities of smaller cameras.

The system does not come with an RC controller, although it is an optional extra for $99.

Although you can purchses prop guards the manufacturer suggests removing tham during filming as they destabilise the system in flight.

News – Dronecode Project

The Open Source Dronecode Project has been announced under the auspices of the Linux Foundation, it will bring together existing projects including the APM/ArduPilot and PX4 open source autopilot systems as well as advancing new technologies. It will provide a common platform for Drone and robotics opens source projects aiming to unite the open source industry.

The maker community has already dramatically increased the development of drones and the Dronecode Project is hoping to advance the technologies required and both improve them and make them more affordable.

The Linux Foundation can provide an existing organisation and collaborative framework allowing the the Dronecolde Project to concentrate on the innovation of new technology.


News – 3D Robotics announces partnership with Intel

3D Robotics has announced a partnership with Intel in which they will be using the new Intel Edison for development of their autopilot systems. The Intel Edison is a microcomputer the size of a postage stamp which provides the power of a personal computer.

The extra processing power of the Edison will allow a person or object to be tracked with the follow me technology of the Pixhawk autopilot. So a person can be filmed automatically with the camera on the UAV (unmanned aerial vehicle) by tracking the person without the need for them to carry a mobile device, with its reliance on a less accurate GPS signal, as the UAV will be able to visually recognise a person.

It will also allow developments in image processing, sense and avoidance with new classes of sensors allowing further developments of autonomous UAV flight and object avoidance.


The IRIS+ is the latest in a range of open source UAVs (Unmanned Aerial Vehicles) from 3D Robotics, an open source hardware and software company. It is designed to carry the GoPro cameras, comes with an autopilot system and provides 16 minutes of flight time fully loaded with camera and gimbal.

It improves on the previous version of the quadcopter.

  • 16-22 minutes flight time
  • Payload capacity 400 g (.8 lbs)
  • Follow me technology


It comes with an open source autopilot system developed by Pixhawk which allows mission planning involving flight between waypoints and automated grid pattern flight which takes into account the type of camera used.

A number of different free software solutions can be used on different platforms to program the UAV: Droidplanner 2 software on the Android , Mission Planner on Windows and APM Planner on OSX operating system.

The Pixhawk autopilot system means that the UAV can run automated missions recording topographical features to create a digital elevation model. This software also enables the quadcopter to use Follow ME technology which follows the operator, altering the camera angle with the gimbal when necessary.

What adds additionally to the usefulness of this autopilot system, is the fact that it is not tied to the UAV, it can also be used on other types of copters, planes, ground rovers, cars and boats – https://pixhawk.org/modules/pixhawk.

The IRIS+ costs $960 with a 2-axis gimbal.

The IRIS+ is a high quality budget quadcopter with many useful abilities out of the box, such as an autopilot, which other systems do not. The similar DJI Phantom 2 series requires additional hardware and software which attaches to the UAV system – DJI iOS Ground Station inc 2.4Ghz Data link and Bluetooth Module – and costs an additional £124.

3D Robotics is a company which is part of a large amateur Unmanned Aerial Vehicles community providing expertise in all aspects of the hardware, software and flying and photography skills. In fact the co-founder of the company, Chris Anderson, also founded the website DIYDrones.com.

The release of this may have been the reason the market leader in camera drones/quadcopters, DJI, reduced the prices of their quadcopters, some by as much as $200 – http://www.dji.com/info/news/phantom-2-series-price-drop

As it is a quadcopter it is limited to lifting cameras the size of a GoPro.


The AirDog is another Kickstarter auto-follow drone “designed for sports enthusiasts, outdoor fans and indie moviemakers”. Unlike the similar HERO+ the AirDog doesn’t use a smartphone as the control interface for the drone to follow, but instead it uses an AirLeash. The system uses the Pixhawk autopilot system.


The AirLeash comes with a number of modes.

  • Auto-follow – where the AirDog follows the user.
  • Relative position follow – where the AirDog retains a set distance to the user while following.
  • Follow track – where a route is recorded by flying the AirDog which can then be repeated in the smartphone app.
  • Hover and Aim – where the AirDog hovers in one position while following the movement of the AirLeash.
  • Circle – where the AirDog circles the AirLeash at a set distance and altitude.
  • Look down – the AirDog will record action below it.

Although the AirDog can be controlled completely by the AirLeash the iOS and Android apps allow the distance, height, and angle to be controlled. It carries a GoPro camera in its protective plastic case within a 2-axis gyro-stabilized gimbal.


The system cost $1,295 with a 2-axis gimbal, although this appears to be a pre-order reduction from $1,495. An additional Airleash can be purchased for $295. The AirDog has a 10-20 minutes flight time depending on the speed it is flown at.


Both the AirDog and similar system, the Hexo+, have the ability to follow a person carrying a smartphone or other device, keeping them in frame for the whole time frame of a video would seen to have great potential for the recording of site tours, which could now be recorded automatically from different altitudes showing the whole or parts of an excavation. The audio could be recorded with a digital recording device attached to the tour guide, with the audio and video being combined in post production.

They would also have the potential to record fieldwalking and exploration looking for new sites in remote regions.

The BBC has already begun to used UAV systems in the recording of news items – http://www.bbc.co.uk/news/business-24712136http://www.bbc.co.uk/blogs/researchanddevelopment/2012/04/collab-soton-uav.shtmlhttp://www.bbc.co.uk/programmes/n3csw972

Not only is the AirDog impact resistant, it is designed to be flown through wind, waves, rain, sleet, and snow which should cater for the British weather which would limit the flight of other systems. It’s design also allows it to fold up and fit into a backpack, making it very portable.

The AirDog is specifically designed for autonomous flight so it does not come with an RC (Radio Control) Controller, it can however be switched to manual and an RC Controller bought separately can be used to control it like a standard UAV, although this obviously adds to the cost.

The recently released IRIS+ quadcopter has limited the usefulness of any small UAV with “follow-me” technology, as not only is it a system with an RC controller and an autopilot that can be used to photographically map areas, but the system also has “follow-me” technology which matches that of other systems. It closely matches the lowest price of the AirDog as well.

The limitations of the system would be closely linked to the limitations of the GoPro camera which it uses to record.

The AirDog project rejected the use of smartphones for a number of reasons:

  • Problems with using smartphones in extreme conditions – this is unlikely to be a problem.
  • The average smartphone has only a 5-10m GPS accuracy horizontally, which is worse horizontally.
  • Smartphones generally only have a 30-50m range for Wi-fi and Bluetooth which could cause potential problems if the UAV lost its signal – this would be less of a problem with site tour recording.

The six propellers of the HEXO+ make it the more stable of the two systems and more capable of landing if one motor were to fail.