A basic assumption is that the three-dimensional shape of all particles is the same and independent of the size of the grains (Sandstro¨m, 1995). However, results from this study demonstrate that this is not the case for the fine material, see Fig. 3. Generally, aggregates larger than 0.25 mm in size are substantially more rounded if it is a natural gravel and are more square if it is a crushed rock.
In this project a ProgRes camera with a resolution of 3000×2400 pixels per image and 36 bit colours was used for image production. A normal video camera has a resolution of about 650×450 pixels