A number of factors make determining the attenuation difficult using this method. First, the difficulty comes from the effects on the seismic spectrum from interference of different seismic arrivals, so it is necessary to carefully window the desired reflector or variable-window time-frequency transform. Second, angle-dependent effects (directivity, anisotropy, raypath differences) hamper accurate interval measurements. Third, geometric information (local velocity, dip event, opening angle) must be taken into consideration in the image domain.