(517h) Development of a New Method to Determine a Three Dimensional Topographic Image from One Picture Taken by a Normal Digital Camera

Topographical data of a surface is normally obtained by using two cameras simultaneously and/or red and blue color filters. Here we will introduce a new imaging method with which it is possible to get the topographical data from a single picture taken by a normal digital camera. The measuring system has numerous applications in 3D imaging.

In the current method a practically flat surface is illuminated from three different directions using three primary colors (red, green and blue). Then only one color picture is taken by a normal digital camera using 1 ms illumination. From the obtained data this new method can directly build a realistic topographic picture from the object surface. Thereafter it is straightforward to calculate for example surface roughness or particle size distribution from the image data. Our method has been tested widely in particle size analysis in various cases.

Off line and at line determinations were made using various particle size fractions raging from 50 um to 1500 um. These determinations were made using a microscope stand having X-Y adjustment unit. In the in line testing the measuring system was installed in a fully instrumented fluid bed granulator, and the determinations were made directly from the granulation chamber through a window using a special in line sampling system.

Off line and at line determinations are simple and they don't need any special sample preparation. Particle sizes were measured with a high accuracy. It is evident that the measuring range can be broadening by selection of proper optics. In the in line determinations it was challenging to keep the measuring window clean. Therefore a new special in line sampler was developed. Our new method is able to follow accurately the granule size enlargement in a real time.