Stereovision Drone

Pietro Grimaldi, Italy

FIG Commission 3 Workshop 2014

Geospatial Crowdsourcing and VGI: Establishment of SDI & SIM

Bologna, Italy, 4-7 November 2014

Key words: Alberobello, Coifa, Drone, Stereovision, Uav.

Summary

The presentation describes the experiences gained during the course of the 5th edition (17 to 26 July 2014) of the Intenational Summer School entitled "Survey for Planning: New Technologies and Land Protection".

In particular, the experiences of survey with the use of "drone" indoor ("Santa Maria della Vetrana" and "Grave of the Caves of Castellana Grotte") and external ("Santa Maria della Vetrana" - http://youtu.be/dcdDN22LJto and district "Aia Piccola" of the City of Alberobello, a UNESCO heritage site).

In addition, we illustrate the problems of using stereo-camera for shooting indoors with drone (drone stereovision)

In this case it would illustrate:

· shooting stero with drone;

· preparatory operations (ground control points - control points on the ground) with the use of "drone" performed by surveyors enrolled in the Collegio Provinciale dei Geometri e Geometri Laureati of Bari;

· instrumentation and the drone used;

· realization of flights;

· first results obtained.

It will highlight the real issues (in real work applications) relating to the use of "drones".

The examples would be:

· the Franciscan Monastery and the Church of "Santa Maria della Vetrana" in Castellana Grotte (http://youtu.be/dcdDN22LJto );

· the "Grave of the Caves" of Castellana Grotte;

· the district "Aia Piccola" in the town of Alberobello, a UNESCO heritage site.

Objectives

The Collegio dei Geometri e Geometri Laureati of the province of Bari and the Comitato Italiano Fotogrammetria Architettonica - COIFA organized in Puglia, 17 to 26 July 2014, the fifth edition of the International Summer School "Measure for Planning: New Technologies and Land Protection" and offered its members the opportunity to study and optimize the use of "new technologies" for the defense of the territory.

The project of the International Summer School aims to:

• start the "continuous and ongoing research" in science and technology to investigate and exploit the opportunities offered by new technologies to the "survey", "knowledge" and the "land protection" in line with the purposes of the Statute of the Comitato Italiano Fotogrammetria Architettonica - COIFA; in fact underlying the actions COIFA there is a firm awareness that there can be no economic development without innovation and without innovation scientific research;

• promote the fundamental principle that animates the work of the editions of the International Summer School, "the documentation is itself a cultural process that can not be delegated to a third party" (Mons.Prof.Pietro Amato);

• examine the environment as a "key" to interpret the future, and unite in one aspect the history of the places with the use of new technologies for the "survey", "knowledge" and the "land protection" of the same places;

• clarify that the survey operations are not limited to determine the form and position of "building structures and urban" environment;

• ensure close collaboration between students, teachers and professionals, both domestic and foreign.

The study environment is the meeting point between the business and academic world, the study is the encouragement to give strength to a new culture, a culture that is confident for the union of history and new technologies, the study and the protection of cultural heritage through the eyes of new tools for the investigation (survey) of the area or an element defined as a "living organism".

Method

The philosophy of teaching, which is behind the project of the International Summer Scool, is to recover the old concept of "school-workshop" in which the student works closely with the teacher and ends up taking the role of the teacher himself

It has implemented a common path of study that brings together engineers for the survey, historians of art, the business community and university researchers.

Given that teaching must be understood for the transmission of "how to do" the Disciple, is to remember that it is possible only if certain conditions are met, namely:

• clear definition of teaching;

• the ability of the Master of "knowing how to operate", since "knowledge" without "being able to operate" is equivalent to "not know";

• the estimate of the Disciple to the Master, based on knowledge from the Disciple, what the Master himself did;

• estimation of the Master in relation to the disciple, based on knowledge of what the Disciple can do the same;

• free choice of the Master to the disciple;

• the free acceptance of the Disciple of the Master.

Casework

Among the various activities carried out during the operation of land surveying, as some elements of architecture, urban planning and subsoil of the "Valle d’Itria" considerable interest was the use of drones in the survey.

In particular, the study experience with the use of "drone" in the internal ("Chiesa di Santa Maria della Vetrana" and "La Grave delle Grotte di Castellana Grotte") and external ("Church and Franciscan Monastery of Santa Maria della Vetrana "and part of the old town called "Aia Piccola" of the city of Alberobello, a UNESCO World Heritage Site).

Finally, we tested the use of stereo-camera, carried by drone (UAV stereovision) for indoor shooting.

The phases illustrated are the following:

• stereo photos taken with drone;

• preparatory operations topographic (ground control points) for the use of "drone" performed by surveyors enrolled in the Collegio Provinciale dei Geometri e Geometri Laureati of Bari;

• instrumentation and drones used;

• the operation of flights;

• first results.

Photo stereo drone captured by Naza 650 Quad V2:

use of stereo-camera mode "normal case"

It was created a stereo-camera using two cameras "Mobius ActionCam"

the parameters of which are reported in the following table and in which is shown the type of camera used (line orange color)

The cameras are upright on a bar made of carbon fiber with dimensions of length 100.00 cm, 3.00 cm width, 1.00 cm thickness and reinforced with tubular diameter of ½ inch, mounted under the support base of the photo cameras. The weight of the "stereo-camera Mobius ActionCam" with the slots was placed 290 grams.

“stereo-camera Mobius ActionCam”

The "stereo-camera Mobius ActionCam" was attached to the drone Naza 650 Quad V2

Experience has the aim to produce stereo pictures to be used for the qualitative analysis, by means of the observation sites of the stereo object of study, and as a second objective to evaluate the possibility of using the pairs of stereo photos with the program StereoFot, conceived and realized in the teaching and research Laboratory of Architectonic Photogrammetry, Polytechnic of Bari since 1990, managed by Prof.Ing.Antonio Daddabbo, and subsequently developed, and even today, Dario Daddabbo together with the aforementioned Laboratory of Architectonic Photogrammetry, directed by scientifically Prof.Arch.Claudio D'Amato Guerrieri

The possibility of using stereo images, taken with the "stereo-camera Mobius ActionCam" in the program StereoFot will be possible because the stereo photographs were made respecting the principle of the "normal case" as shown below

With regard to the calculation of the distances of the cameras "Mobius ActionCam" proceed with the use of the inverse formulas of the general principle of the "normal case" above, as explained in my previous job at the XXII ISPRS Congress in Melbourne , 2012 (Stereometric Modelling)

Finally, please note that while working for the International Summe School, has also been made stereo movie with the "stereo-camera Mobius ActionCam"

Surveying (ground control points) for the use of images acquired with "drones" performed by surveyors enrolled in the Collegio Provinciale dei Geometri e Geometri Laureati of Bari

Church Santa Maria della Vetrana

Surveying Control Points out by the surveyors Massimo Caldarola and Giovanni Bruno of the Collegio Provinciale dei Geometri e Geometri Laureati of Bari led by Pietro Grimaldi

The topographic survey, ground control points (target 40 cm x 40 cm)

made at the "Convento Madonna della Vetrana" in Castellana Grotte (BA), was performed with Nikon DTM 310 Total Station.

The object of the survey was to detect certain points of detail and especially the church, the convent and some points on the road, it has also detected a fiducial point (PF13 of Fg.35) point set up by the Agenzia Entrate Bari with cartesian coordinates.

The instrument was placed on the flat roof of the convent to detect points of the terrace to represent the points graphically details.

The booklet measures was performed with polar coordinates, as shown in the diagram attached

The development of the survey was executed with PFCAD program to transform polar coordinates to absolute as to document the relationship of the measures can be seen to have found a point of detail (topographic point 105) that corresponds to the PF13 Fg. 35.

Grave of the Caves of Castellana Grotte

Topographic control points by the surveyor Vitantonio Micoli coordinated by Peter Grimaldi

The topographic survey, ground control points (target 40 cm x 40 cm), performed in the "Grave of the Cave of Castellana Grotte", took place with the following:

· location of the site (about 5000 square meters and a height of approximately 60 meters)

· Placement of 10 targets (40 cm x 40 cm)

· Setting up of Total Station Topcon IS 201i and survey of targets located:

we proceeded to the survey of 8 targets mode survey celerimetric targets, carried out by positioning the center of gravity of the "prism" on the same target. Being in the cave, the lighting conditions were not optimal and the identification of the "prism", located on the target, it was possible thanks to the automatic search of the same "prism", performed by the robotic total station. The coordinates of the target are shown below

· Time of survey of the coordinates of the targets: 2 hours

Historic center of Alberobello "Aia Piccola"

Surveying of the control points by the surveyor Vitantonio Micoli coordinated by Peter Grimaldi

The surveying, ground control points (target 40 cm x 40 cm), made for the part of the historic center of Alberobello, called "Aia Piccola", took place with the following:

• Identify area (about 20 hectares)

• Positioning of 12 targets (40 cm x 40 cm)

§ Setting up the GPS (Hiper Pro GPS + GLONASS dual frequency - Topcon) in RTK mode with the use of "base" and "rover" and survey operations carried out with GPS: in this case we have worked with the placement of the "base" in the top of a building adjacent to the area to survey, called "Aia Piccola" (distance of 220 meters from the center of gravity of the area to survey). The coordinates of the "base" have been determined by taking advantage of the GNSS PUGLIA network as the following diagram

The coordinates of the "base" (Lat 40 ° 47'06,32319 ", Long 17 ° 14'20,56739" +474.412 altitude above sea level) were determined by querying the "permanent basis" called "FASA" in the municipality of Fasano (BR). The detection of targets was performed by positioning the center of gravity of the "rover" on the same target, getting the coordinates listed below

with the relative accuracies in sqm in horizontal and vertical. It is noted that for each target were performed 20 "beats" with the study of the relative standard error ellipses. Considering that it is operated in the town and in order to obtain greater accuracy in determining the coordinates of the target and avoid the "fall" of the signal it is operated using the "base" and "rover". The survey data were recorded in the field with handheld Topcon FC-200 and Mercury software (Geopro-Geotop Ltd., Ancona) and processed with software Meridiana (Geopro-Geotop Ltd., Ancona);

§ Time survey of targets: 1h

Surveying Equipment and Drones used

Nikon Total Station DTM 310 (Church of St. Mary of Vetrana)

Total Station Topcon IS 201i (Grave of the Caves of Castellana Grotte)

Hiper Pro GPS, GPS + GLONASS dual frequency - Topcon ("Aia Piccola", Alberbello)

The drones "Naza 650 Quad V2" and "MikroKopter Okto XL" carriers were used for the acquisition of images for the "Church of Santa Maria della Vetrana" (internal and external "Naza 650 Quad V2") for the "grave of the Caves of Castellana Grotte "(" MikroKopter Okto XL ") and for part of the historic center of Alberobello called" Aia Piccola "(" Naza 650 Quad V2 ")

“Naza 650 Quad V2”

“MikroKopter Okto XL”

The Drone is a Naza_650_Quad_V2 with electronic NAZA V2 GPS IOSD (on screen display), Mini DJI (brand name) and NAZA autopilot with PMUV2 and Ground Station Naza (ground control system with proprietary software for the Naza flight planning: path , altitude, speed horizontal and vertical) - Frame Carbon TAROT 650 - Gimbal Tarot Brushless 2D - GOPRO Camera Black Plus - Radio FUTABA CG10 - system led lipo battery 6000mAh 40C 4celle (16.8 volts) + service battery 3-cell (12, 6 volts) 500mAh- video transmission system grounded on 5.8GHZ - receiver with 7-inch LCD monitor.

TYPE	MikroKopter Okto XL http://mikrokopter.de/ucwiki/en/ArfOktoXL
	SYSTEM OF FLIGHT MK-FlightCtrl ME (ACC-Upgrade) MK-Navi-Ctrl MK-GPS con GPS-Shield MK-Telemetry system mod. Wi232 MK- SmartOSD Batterie Lipo 8000mAh Gimbal brushless 2 assi con scheda di controllo Alexmos Sistema di trasmissione video (microcamera + trasmettitore video) GROUND STATION: Radiocomando Spektrum 8 canali Down link video Monitor
PAYLOAD	Canon PowerShot SX260 HS con GPS
	(A) ALTIMETER HOLD: the model can be locked to a predetermined height (B) GPS HOLD: the model can be locked to a predetermined position with the help of the GPS module (within 1-3 meters without wind - within 3-12 meters with the wind) (C) COMING HOME: the model in the case servant can return to the starting position in automatic (D) POTIFREE: With this function you can change the orientation flight of the flight (E) ROOM: Moves the camera to a preset position (F) WAYPOINTS: navigation ground automatic programmable by the user
WEIGHT MODEL	1830g (without battery)
ENGINES	8
DIAMETER	77cm
BATTERY	4s – 8000mAh
TIME OF FLIGHT	10 min (according to the payload and battery used)

The software used for processing images captured by the "drones" is Pix4Dmapper Discovery (http://pix4d.com/download/)of Pix4D

Realization of Flight

It is reported, for example, the flight data acquisition through the old town "Aia Piccola" of Alberobello, which you can view the following links:

http://coifa.it/filmati/alberobello.mov (short movie)

http://coifa.it/filmati/alberobello.mp4 (long movie)

First results obtained

In addition to the results already shown to paragraph “Photo stereo drone captured by Naza 650 Quad V2: use of stereo-camera mode normal case", are positive results obtained from the use of the software Pix4Dmapper Discovery (http://pix4d.com / download /) of Pix4D infact with 7 minutes of flight, with the click of 420 aerial photos with the drone "Naza 650 Quad V2", with the click of 180 ground photos with camera GOPRO Black Plus has built the model of the Church of St. Mary of the Vetrana available at the following link http://youtu.be/dcdDN22LJto

Below are some job file

A special thanks to Mauro Lobascio and Gianni Gadaleta for technical and operational support for the realization of flights with the use of drones and thanks to Gabriele Ruggiero, Direct Sales Manager of Pix4D for software support received.