As the pixel pitch of an X-ray detector decreases, the crosstalk and charge-sharing effects become dominant. The decrease in pixel pitch is also directly related to a reduction in input photons per pixel. Thus, the noise of individual pixel increases in both direct and indirect detectors. In photon counting detector, photon energy shift due to charge sharing and blurring in indirect charge integration detector increases greatly. In this study, we propose the detector shift iteration method (DSIM), which improves both image quality and spatial resolution by solving the abovementioned problems. The Modulation Transfer Function (MTF) and Signal-to-Noise Ratio (SNR) are measured to analyze the image quality and spatial resolution, and the improvement in image contrast is analyzed through various object images. The analysis showed sufficient improvement in both the quality and spatial resolution of the DSIM images. In particular, the DSIM images had better quality than those obtained by sensors with the same pixel pitch as virtual pixel pitch.