Texture-based hologram generation using triangles

The synthesis of holograms by computer requires the calculation of the complex amplitude emitted by an object in the hologram plane. Several approaches exist that decompose the object into primitives like points and lines. We assume that the object to be imaged can be approximately decomposed into congruent triangles. In a preprocessing step, we calculate wavefields for the triangle whose transformed copies build the object surface. The computed wavefields represent triangles rotated by different angles and positioned in different depths. The resulting wavefields are stored as conventional color images with alpha channel (textures) in a lookup table indexed by rotation angle and distance from the hologram plane. Each pixel in the texture codes a complex number. Every triangle of the input object has a corresponding entry in the lookup table. The rotation angles and the distance of the triangle determine the selection of the appropriate texture. The textures are rendered using special graphics hardware, and interference is simulated. The lookup table helps to react immediately to transformations of the input object. Texture swapping and repositioning according to the object movings lead to full-parallax hologram generation for small objects in real-time.