Application of X-ray CT for detection of physical foreign materials in foods
1998
Ogawa, Y. | Morita, K. | Tanaka, S. | Setoguchi, M. | Thai, C.N.
A medical X-ray CT scanner was used as a non-destructive inspection method for t he detection of selected non-metallic materials embedded in various fluids and f ood materials. The X-ray absorption characteristics of tested materials were exp ressed as X-ray CT numbers. It was found that the CT number of a foreign object was affected by a systemic error (a point spread function), even if its size was greater than 1 pixel in the video image provided by the scanner. Within the int erface region between the foreign object and its surrounding matrix, CT numbers were found to vary smoothly between characteristic values for the object and the matrix thus pointing to important effects to consider when developing X-ray CT techniques for the detection and identification of foreign materials in foods. S pecific threshold values for CT numbers of selected foodstuffs were defined for successful detection of foreign materials. This study also pointed out the limit ation of using X-ray linear absorption coefficients from typical CT systems to d etect certain combination of foreign materials and foodstuffs.
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