Methods and systems are provided for reducing aliasing artifacts in images generated in an imaging system, such as a computed tomography (CT) imaging systems. In one embodiment, a method comprises receiving a filtered signal generated by passing a primary signal through a collimator having a non-rectangular transition profile, the collimator positioned between an object and a detector of an imaging system, and generating an image based on the filtered signal received at the detector, the primary signal including radiation from a source of the imaging system attenuated by the object placed between the source and the detector. In this way, by filtering the signals at the collimator before reaching the detector, aliasing artifacts in the images may be reduced.