Noise addition is a simple but effective method for generating a phase-only hologram (POH) of an object. Briefly, the intensity image of an object is added with random phase noise and converted into a digital Fresnel hologram. Subsequently, the phase component of the hologram is retained as the POH. Although the method is fast and the visual quality of the reconstructed image is acceptable, the edges and lines patterns are heavily fragmented. In this Letter, we propose a method to overcome this problem. An experimental evaluation based on numerical and optical reconstructions reveals that a hologram generated by our proposed method is capable of preserving line patterns with favorable quality.