Design and Implementation of Special-Purpose Computer for Incoherent Digital Holography

We designed and implemented a special-purpose computer for incoherent digital holography for application in three-dimensional (3D) microscopy. We focused on multiwavelength-multiplexed phase-shifting incoherent color digital holography as a method for acquiring 3D color-reconstructed images. This method records holograms faster than conventional temporal division methods. However, the reconstruction calculation of this method requires a significant amount of time, similar to the conventional method. Therefore, we designed a circuit for high-speed image reconstruction. We designed a Fresnel diffraction circuit that requires repetitive calculations to obtain a 3D color image but incurs a high calculation cost. We implemented the circuit on a field-programmable gate array (FPGA) and successfully calculated reconstructed images that were of the same quality as those calculated by the central processing unit (CPU) of a personal computer (PC). The calculation time was approximately 2.6 times faster than that of the CPU.