Ray-tracing image simulations of transparent objects with complex shape and inhomogeneous refractive index

Optical images of transparent three-dimensional objects can be different from a replica of the object's cross section in the image plane, due to refraction at the surface or in the body of the object. Simulations of the object's image are thus needed for the visualization and validation of physical models, but previous image simulations for fluid dynamics showed significant differences from experiments. We report ray tracing image simulations that replicate with high fidelity brightfield microscopy images of drops with complex shapes, and images of pressure and shock waves traveling inside them. For high fidelity, the simulations must replicate the spatial and angular distribution of illumination rays, and both the experiment and the simulation must be designed for accurate optical modeling. These techniques are directly applicable to optical microscopy and expand the type and the accuracy of three-dimensional information that can be extracted from optical images.