Holography is the ultimate 3D image technology which can display natural 3D images for humans because it records and
reconstructs the wavefront from objects. Previously, we had studied the holography of real scenes and proposed a color
hologram generation method using the same viewpoint for images of a real scene; i.e., color image and depth map.
Although the images reconstructed from the hologram were in full color and in a high-resolution format called 8K4K,
the observed range was only 5.6 degrees, which was insufficient. In this paper, we propose a hologram generation
method with viewing-zone-angle expansion. First, object beams are calculated for the light that propagates in the
different directions and satisfies the maximum diffraction angle. Second, holograms reconstructing the different viewing-zone-
angles are generated by irradiating with reference beams that have different incidence angles. As an experimental
result, the reconstructed images were observed over a wide range and we confirmed the effectiveness of the proposed
method. At this time, to apply a method which calculates the light propagation with FFTs because the amount of
calculation had tripled, we confirmed that the processing speed is nine times faster than that achieved previously.