Evaluation of two Software Tools dedicated to an Automatic Analysis of the CT Scanner Image Spatial Resolution

An evaluation of two software tools dedicated to an automatic analysis of the CT scanner image spatial resolution is presented in this paper. The methods evaluated consist of calculating the modulation transfer function (MTF) of the CT scanners; the first uses an image of an impulse source, while the second method proposed by Droege and Morin uses an image of cyclic bar patterns. Two digital test objects (DTO) are created to this purpose. These DTOs are then blurred by doing a convolution with a two-dimensional Gaussian point spread function (PSF_Ref), which has a well known full width at half maximum (FWHM). The evaluation process consists then of comparing the Fourier transform of the PSF on the one hand, and the two mentioned methods on the other hand.