Hologram
- Computer-generated hologram(CGH) : digitally generated hologram based on light diffraction simulation
- Hologram for virtual object represented by point cloud or mesh
- Numerical reconstruction for verification
- Optical reconstruction by SLM(Spatial Light Modulator) or holographic display
- Popular CGH methods : basically numerical methods for light propagation
- Point-based raytracing method
- Fresnel/Fraunhofer diffraction method
- Angular spectrum method
- Technical skills : Scalar diffraction theory, Fourier optics and Fourier transform, Fast Fourier transform(FFT)
- Why hologram?
- Next-generation digital content which provides natural 3D experience without wearables
Surface details with texture image in polygon-based CGH(2019)
Surface details with texture image in polygon-based CGH(2019)
- FFT-based fast calculation
- Full texture techniques : arbitrary texture image and uv-coordinates
- C++ CGH API
- User-friendly FFT and convolution
- Light propagation method : Fresnel/Fraunhofer transform, angular spectrum method
- CGH generation method : point-based raytracing, mesh-based angular spectrum
- All calculation methods support high-performance GPU computing(CUDA).
- Point-based CGH : fringe pattern(left) and reconstruction result(right), #pts=144647
- Mesh-based CGH : amplitude and phase(left) and reconstruction(right)
- Interactive hologram using spherical angular spectrum
- Conference paper : Interactive computer-generated hologram using spherical angular spectrum, Digital holography and 3-D Imaging 2016
- Cylindrical angular spectrum for point cloud and fast hologram generation
- Journal paper : Cylindrical angular spectrum using Fourier coefficients of point light source and its application to fast hologram calculation, Optics Express, 23(23) 29555-29564, 2015 (selected as cover image!)
- Explicit formula for angular spectrum of a point light source
- 360 hologram generation using cylindrical angular spectrum with occlusion culling
- CUDA OptiX library for ray-tracing computations
- Journal paper : Cylindrical angular spectrum using Fourier coefficients of point light source and its application to fast hologram calculation, Optics Express, 23(23) 29555-29564, 2015 (selected as cover image!)
- Object distance extraction from CGH using frequency analysis
- Journal paper : Fast focus estimation using frequency analysis in digital holography, Optics Express 22(23) 28926-28933, 2014
- Fast frequency-based focus distance calculation without numerical reconstructions
- Journal paper : Fast focus estimation using frequency analysis in digital holography, Optics Express 22(23) 28926-28933, 2014
(a)(b) : Amplitude and phases of hologram, (c) numerical reconstruction at computed distance, the rightest is the density distribution of the intersection of local rays which predicts the exact focus distance