Generalized-Scintillation Detection and Ranging (g-SCIDAR) has proven to be the most reliable and efficient technique for obtaining the vertical structure of the atmospheric turbulence through optical means. However, undesirable turbulence inside the telescope enclosure (dome and mirror seeing) is intermixed with the results. Processes for rejecting this contribution have been used indirectly when the vertical wind profiles are obtained. With a view to introducing the routine use of g-SCIDAR technique in multiconjugate adaptive optics applications, we propose a simple method, based on evenness properties with Fourier analysis, for rejecting the dome and mirror seeing in C2n(h) profiles. The method is suitable for implementation in real time and could furthermore be extended to other applications of form recognition, whenever certain conditions of symmetry are satisfied.