Cultural Heritage Object Identification by Radiography Nondestructive Method and Digital Image Processing

Nondestructive testing (NDT) is an important tool in the world of industry. Among different NDT methods, radiography plays a very interesting role both in industry and medicine. Medical and industrial uses of X and gamma rays were recognized since more than 1 century ago. One of the interesting uses of radiography is in archeological and art applications. In this research, radiography was utilized for identification of a damaged art-historical material. The subject is a brass tray belonging to Iran cultural heritage with an estimated age of about 3500 years. The tray was found in Lorestan province and referred to as “Lorestan bonze”. The object was damaged seriously due to heavy corrosion attack. Therefore recognition of the object was a major problem. Normal radiography method can help for object determination, but it suffers some major drawbacks related to contrast and thickness measurement. Image processing technique and a precise thickness measurement method were added to digitized radiographs. A precise radiographic thickness method was introduced and used before for the pipeline radiography. For digital image processing, Canny edge detection method and Gaussian filter were used. Radiography image obtained from this work showed a very clear picture of the original trace of hammered design. These results showed that a combination of radiography, image processing techniques and consideration of physical principles of radiation interaction with materials can produce a very clear image which can be used effectively for hte detail analysis of cultural heritages.