Translations:Rays/7/en

What is ray tracing? When a propagating wave encounters an inhomogeneity, the wavefront will change direction. Rays are curves that trace the motion of the wavefront over time. Recall the story of Hansel and Gretel. As they went into the depths of the trees, Hansel dropped a little white pebble here and there on the mossy green ground. Night fell. However, the tiny white pebbles gleamed in the moonlight, and the children found their way home. In other words, Hansel and Gretel used the pebbles to backtrack their way to their home. Ray tracing can be used to backtrack the paths of the received reflected events back into the earth and place their energy at the point of reflection. We now will describe the behavior of the rays and wavefronts in media with a continuously varying velocity.