X ray CT system is used for nondestructive inspection in industrial field. But there are some problems when we get the inner images of flat objects, namely rate of expansion and beam hardening. This study aims at solving these problems by developing scan system with the use of new sinogram restoration techniques. Although there is a lack of projection data, the proposed system enables to reconstruct a region of interest accurately with high rate of expansion. The supportive simulation results show that the proposed method can get inner images of plate shaped objects without suffering from beam hardening.