Simulation of reflected sunlight using a voxel model in a forest

Abstract

Nowadays, products of satellite imagery are used in many research fields. To verify accuracy of products, inverse estimation for radiance is applied by ray tracing using physical model. Usually, forest model which combined simple shaped tree has been used as a physical model. However, the model can't represent complex structure of a forest. Voxel model is one suitable model that can represent complex structures of a forest. In this research, red band of aerial images was simulated by ray tracing of sunlight using a voxel model. The test area was selected evergreen broad-leaf forests, evergreen needle-leaf forest and deciduous broad-leaved forest in the deciduous period. At evergreen broad-forests and evergreen needle-leaf forest, shadow and shade was simulated. At deciduous broad-leaved forest, scattering cross section was simulated. As a result, the correlation coefficient was 0.638 at evergreen broad-leaf forests, 0.729 at evergreen needle-leaf forest and 0.630 at deciduous broad-leaved forest. Our proposal method was suitable to simulate reflected sunlight using a voxel model in a forest because the correlation coefficient showed over 0.6. For future works, we improve our method by consider multiple reflections and atmospheric effect.