This research aims to explore the potential of low cost video camera for 3D
modelling of large historical monuments. As we know, photos extraction is a fundamental
issue in any photogrammetric project. In fact, cost and time are dependent on photo
extraction method. Usually, photos are taken one by one assuring that every object point is
on two photos at least. This operation is time consuming in large scenes modelling. In the
other hand, video record is a simple operation and requires short time comparing to
traditional photo shooting. Then, it will be useful to suggest an approach to use video
recordings as a source of photos required for 3D modelling.
In the present study, we will evaluate the capability of two video cameras. The first
one is a commercial independent camera and the second is associated with a mobile
phone in the extraction of photos required for 3D modelling of a relatively large objects. It
should be noted that the resolution of video frames in mobile phone cameras (comparing to
professional ones) is less than the resolution of ordinary photos. Hence, 3D models
resulting using these frames will be good for applications that don’t require high precision.
The main objective of this research is to study the effect of the accuracy of images'
geometric resolution only on the geometric quality of the resulted three-dimensional
model. In this research, all factors that affect the quality of the model are
fixed and the
geometric resolution is changed only for the used images.
The number of captured images, the number and the distribution and the accuracy of
control points, the camera being used and whether or not it is calibrated, are among the
most important factors influencing the modeling process. In order to neutralize the effect of
the inner parameters of the used camera, a process of calibration was achieved. On the
other hand, we have pre-planned the process of photography to avoid problems resulting
from the lack or increase the number of images, that directly affect the quality and
completeness of the model. In addition, accurate control data obtained from precise survey
work (horizontal geodetic network and leveling network) was applied.
In this study, we examined the effect of image resolution on the generation of a dense
cloud of points by applying the Structure from Motion (SfM) and deducing the surface
model and the orthophoto of a facade of a building at Tishreen University.
