Transcript Using Photogrammetry

Photogrammetry Workshop
Session 1: Fieldwork Exercise
Chris Leung RIBA
photogrã’mmétry n. Process of making surveys
or geodetic measurements by photography.
Bartlett Diploma Unit 23
Thursday 14th December 2006
Location: Ham Yard London W1
•
Objective
To produce a three-dimensional digital
model of the site using digital images and
the technique of photogrammetry.
• Sequence of Work
1) Understand how to photograph a subject
with images that can be used effectively
by the photogrammetry software.
2) Working with the photogrammetry
software to build a geometry solution.
3) Scaling, Orientation and export of the
geometry to a CAD package.
•
Decide the subject that will be modelled.
•
Take the photographs of the subject from
different angles but keep the points of
interest visible in as many images as
possible. The more points that are visible,
the more there will be to model later.
•
•
When you cannot photograph a subject
from all angles, aim to photograph an
overlap between sets of images.
More images are better too few…….
•
Keep the camera set to the fixed
maximum wide-angle FOV (field-of-view)
at all times.
•
Scale
Chose two points of interest that were
identified earlier and measure the distance
between them. The further apart the points
the higher the probability of a more
accurate scaling.
•
Orientation
Chose a line between two points that lies
in the horizontal plane and use a compass
to record the bearing from the north of that
line.