The goal of the course is to provide students with the mathematical background and the practical skill to model 3D surfaces by photogrammetric techniques. Students will be familiar with digital images acquired from terrestrial, drone, airplane and satellite surveys and with software packages for 3D modelling and mapping.

Lectures will allow students to:
- describe the geometry of a photogrammetric survey;
- estimate the orientation parameters for an object 3D reconstruction;
- understand the algorithms for digital image analysis and in particular for image matching;
- know the photogrammetric products and their productive process;
- approach some research and advanced topics of photogrammetry.

Laboratory activities will allow students to:
- calibrate a digital camera for a photogrammetric survey;
- use photogrammetric software packages for 2D/3D modelling;
- design, perform and process a drone survey;
- apply photogrammetric techniques for kinematic positioning.

1. FUNDAMENTAL EQUATIONS OF PHOTOGRAMMETRY: Review of least-squares adjustment. Geometrical transformations in a plane and in space, 2D and 3D rotation matrices and their properties, central projection and collinearity equations. Normal case of stereoscopy: equations for the computation of the object coordinates and their precision. Internal orientation. External orientation of a single photo (space resection), of a pair of photos (relative and absolute orientation), of a block of photos (aerial triangulation by independent models and bundle block adjustment).

2. DIGITAL PHOTOGRAMMETRY: The fundamental principles: definition of a digital image, formats and compression algorithms. The fundamental techniques of digital photogrammetry: image enhancement and filtering, resampling, generation of image pyramids. The algorithms for the automatic determination of homologous points: interest operators, algorithms of image correlation/matching (feature-based, area-based, relational matching). Automatization of the orientation procedures. Automatic aerial triangulation.

3. THE PRODUCTS OF PHOTOGRAMMETRY AND THEIR PRODUCTIVE PROCESS: Stereoscopic restitution. Digital photogrammetric workstations. Digital terrain models (DTM), digital surface models (DSM) and their generation by means of photogrammetric techniques or by LiDAR. Point clouds and their interpolation for 3D object modelling. Orthophotos, “true orthophotos” and digital photo-planes. The photogrammetric production of numerical cartography and spatial databases.

4. THE SENSORS FOR DATA ACQUISITION: Aerial analogical photogrammetric cameras: image characteristics, analysis of the distortions and calibration parameters. Aerial digital cameras: operation principle (frame cameras and linear array sensors), the basic sensors (CCD and CMOS). Commercial digital cameras for unmanned aerial vehicles (UAV). INS/GPS systems and their integrated use inside the aerial triangulation. Photogrammetric scanners. LiDAR sensors.

5. ADVANCED TOPICS: Terrestrial (close-range) photogrammetry. Remote sensing principles and satellite photogrammetry. Photogrammetry using drones (UAV). Inverse photogrammetry for navigation in an urban environment. Fundamental principles of computer vision.

UAV LABORATORY ACTIVITIES:
- Flight planning of a photogrammetric survey by UAV;
- Participation to an outdoor UAV survey, acquiring digital images with a commercial camera mounted on the aircraft and collecting ground control points by GPS receivers;
- Processing of the data acquired during the UAV survey to compute the DSM and the orthophoto of the observed surface by using different photogrammetric software packages.

OTHER LABORATORY ACTIVITIES
- Photogrammetric restitution by using a digital photogrammetric workstation;
- Digital camera calibration, 2D modelling of a building facade and 3D modelling of a simple object (students are invited to use their own cameras).

Concerning the programme subdivision, the 6 CFU course deals with the fundamental equations of photogrammetry, the digital photogrammetry and the products of photogrammetry; among the advanced topics, it includes the close-range and UAV photogrammetry with the corresponding laboratory activities. The 8 CFU course also includes the discussion on the sensors for data acquisition, as well as the advanced topics related to satellite photogrammetry; a wider range of photogrammetric software packages are shown during the laboratory activities. The 10 CFU course covers the whole programme.

Students are required to know the basics of linear algebra and least-squares adjustment.

The exam consists of two parts:
1. an oral examination on the course topics;
2. a practical project to be done individually or in a team.

In addition to delivering a written report, students are required to give an oral presentation on the development and the results of the practical project. In case of teamwork, the cooperation ability will be evaluated too.

The practical project can be replaced by deliveries on the laboratory activities performed during the course.

traduzione di S. Dequal

translated by P. Stewardson

translated by P. Stewardson

translated by I. Harley and S. Kyle