دانلود رایگان مقاله انگلیسی تصویربرداری و پردازش تصویر در تحقیقات رسانه متخلخل - الزویر 2008

Abstract

Three-dimensional imaging and image processing has become an important part for investigations of fluid distribution and flow in porous media. We describe two methods of computed tomography with different characteristics, namely X-ray- and neutron-based. We give an overview of image processing sequences and their methods. We investigated image enhancement with a focus on filters using partial differential equations, classification and structure identification that we used to prepare our images for quantitative evaluations. These methods are demonstrated on a partially saturated sand sample. Finally, we show an application with soil aggregates where investigations using synchrotron X-rays and thermal neutrons have led to new insights and refined fluid distribution and flow models.

5. Discussion and conclusions

We present two techniques for acquiring images of porous materials, such as soil samples. With our application example, we show how information from the two techniques can be combined to enhance the knowledge of soil transport properties.

Thermal neutrons are optimal for monitoring twodimensional water distributions during dynamic processes at high temporal resolution. From the recorded water distributions the macroscopic transport properties of the sample can be derived. X-ray images show soil structures and water distributions at much higher resolution in three dimensions. These images contain the relevant information to predict transport properties. By scanning the same or similar samples with the two techniques, macroscopic transport properties of porous media can be linked to the microscopic pore geometry. Indeed, combination of neutron and X-ray techniques offers unique possibilities to improve our knowledge of flow and transport in porous media.