Learning outcomes of the course unit
Knowledge and understanding:
The student, at the end of the course, should have a deeper knowledge of surveying discipline, of topography and cartography; should have developed a wide vision of photogrammetry and digital imaging from a theoretical point of view; should have developed a basic understanding of laser scanning applications; should have developed a wide vision of remote sensing applications.
Applying knowledge and understanding:
At the end of the course the student should be capable of performing a topographical and photogrammetrical survey design in every step: calibration, ground point surveying, image acquisition, orientation and restitution and final accuracy evaluation; the student should also be capable of manage and classifying remotely sensed data; practical activities will allow the student to develop basic 3D modelling skills.
At the end of the course the student should have developed basic judgment skills to evaluate the best surveying techniques (in case integrated) to be applied to a generic engineering problem (territorial or architectural survey, reverse engineering application, monitoring activities, etc.) as well as the ability to assess the correctness and quality of a photogrammetric survey.
At the end of the course the student should have developed a good (surveying) terminology and should be able to correctly express concepts and ideas.
The final seminar activities should bring the student to develop a good understanding of the more recent features and issues of geomatics, both in terms of photogrammetric and image processing and of applications of geomatics to engineering: in fact the student should be capable of autonomously investigate such fields.
The course provides basic concepts in design and completion of photogrammetric and laser scanning surveys.
Students are expected to have a good understanding of topography and cartography;
A good understanding of error theory and statistics is also advisable.
Course contents summary
The course aims at integrating basic topographic and cartographic knowledge and skills developed in previous courses and introducing the students to more advanced geomatic techniques such as photogrammetry, laser scanning and image analysis, especially considering remote sensed data. The following topics will be considered: brief review of topography and error theory, analytical photogrammetry, digital photogrammetry, main geomatic/photogrammetric products, laser scanning, remote sensing.
Analytical photogrammetry. Collinearity condition. Projective transformation and image metrology. Interior and exterior orientation. Rotation matrices. Collinearity equations. Object space and image space transformations. Error theory of the normal case. Planar object projection: homographies and image rectification. Exterior orientation: direct and indirect methodologies. Complanarity equations. Relative and absolute orientation. Bundle block adjustment and block adjustment by independent models.
Acquisitions sensors and systems. Lenses and image formation. Films and Charged Coupled Devices (CCD). Spatial and radiometric resolution. Image distortions. Film and digital cameras (metric, semi-metric and consumer cameras). Scanners. Calibration techniques. Image space corrections: radial and tangential distortion, film unflatness, atmospheric refraction. Airborne and terrestrial laser scanners. Georefencing.
Design, acquisition, georeferencing and bundle block adjustment of photogrammetric surveys. Flight planning. Direct georeferencing using GPS and INS. Simulations and block adjustment.
Photogrammetric instruments and measuring techniques. Stereovison and stereorestitution. Stereo and mono-comparators. Stereoplotters. Digital map production and GIS data acquisition. Analogue, analytical and digital stereoplotters. Measurement operations: points, contour levels, gridded and irregularly triangulated DTM.
Digital photogrammetry. Image processing: filtering, convoluting and restoring a digital image. Digital image correlation. Feature extraction. DTM production through automatic image correlation. Multiresolution techniques: image pyramids.
Photogrammetric products. Image rectification and its accuracy. Rectification by differential transofrmation. Orthophotography.
Design and quality control in map production.
Design, acquisition, calibration and restitution of a small close range photogrammetric survey.
Lecture Module 0: Introduction
Brief review of topography and error theory
Variance propagation applied to simple engineering problems
Topographical network surveying example
Lecture Module 1: Analytical Photogrammetry
Projection of a plane - Homography
Stereo restitution in the normal case
A brief review of optics, lenses and image formation
Lab and analytical calibration
Exterior orientation (one image): resection and DLT
Exterior orientation (two images): one step and two step orientation
Bundle block adjustment
Independent models adjustment
Image block design
Analytical calibration of an off-the-shelf camera
Image block orientation
Lecture module 2: Digital photogrammetry
Digital image features
Filtering and manipulating a digital image
Area Based matching
Feature Based matching
Use of a digital photogrammetry software
Lecture module 3: Products
Analogical, analytical and digital comparators
Geometric and thematic restitution
Digital terrain model production
3D modelling of a building
Lecture module 4: Laser scanner
Functioning principles (Time of flight, phase difference, triangulation)
Point cloud alignment
Terrestrial Laser Scanner
Airborne Laser Scanner
First/Last Pulse, Lidar Full Waveform
Laser scanning surveying of a building
Lecture module 5: Remote sensing
Spectrum and electromagnetic radiation
Geometric and orbital features of a remote sensing satellite
Supervised e unsupervised image classification
Remote sensing satellite data injection
Supervised classification of a small area.
K. Kraus, Fotogrammetria Vol. 1,
Levrotto e Bella,
A. Selvini, Elementi di fotogrammetria
Lecture Slides (Available on the Elly web portal)
K. Kraus, Phototgrammetry, Levrotto e Bella (TO)
Slides (pdf format) of in class lectures
The subject is designed for Environmental and Civil engineering students and is developed on in-class lectures presented mainly using powerpoint slides, in-class and on-site practical activities and group in-class and home activities. In the last part of the course seminar activities are offered to the class deepening some of the topics covered in the lectures. Every student is expected to produce a final surveying project assisted by the teaching staff (mid-term revisions).
In class lectures and practical exercise
Assessment methods and criteria
The course is graded based on
Oral exam and
Project development and discussion in which, individually the student is expected to choose an object to be photogrammetrically surveyed (any object having a minimal geometrical complexity can be chosen) providing camera calibration, image orientation and object reconstruction and restitution (3D model, orthophoto, etc.)
Grades will be determined using the following grades and based on the following aspects:
Project development and discussion (50%):
Illustration of theoretical topics (knowledge)
Application of knowledge to a real surveying case (applying knowledge)
Capability of autonomously choose the proper surveying techniques and restitution modes
Oral Examination (50%):
Illustration of theoretical topics (knowledge)
Application of knowledge through exercises (applying knowledge)
Proper use of technical terminology (Comunication skill)
Oral examination with discussion of the project completed in the exercises