The internal structure of ceramic green bodies has been characterised by combining a computer controlled optical microscope with an image analysing system to provide statistically reliable data. The calcined porous alumina ceramic green body was made transparent by utilizing the immersion liquid technique which enabled the interior of the body to be observed. It was demonstrated how internal defects such as pores could be detected using this technique and an automated sequence of obtaining internal structure images and transferring and processing them using an image analysing software system has been developed. The technique proved to be a simple and rapid method of accurately determining the number distribution of pores in an alumina green body.