An apparatus for analyzing two-dimensional input objects comprising an illumination system including a lighting unit, a Fourier transform module and a receiver unit. The lighting unit generates an incoherent illuminating beam of predetermined form and area, for what purpose the lighting unit may include a self-luminous mask or an incoherently illuminated mask. A receiver unit comprises a single detector which is arranged in the optical axis of the Fourier transform plane of the Fourier transform module. The exit of the lighting unit is located on the optical axis and is imaged by the subsequent imaging optical elements (inclusive of the Fourier transform module) at the Fourier transform plane of the Fourier transform module.