Combined ray tracing method based on multi-scale and multi-direction segment-by-segment iteration and reverse tracing

The invention provides a combined ray tracing method based on multi-scale and multi-direction segment-by-segment iteration and reverse tracing. The combined ray tracing method comprises the following steps: S1, taking a tracing result of a conventional reverse tracing method as an initial value of a segment-by-segment iteration method; s2, thinning the original grid to a preset sparsest level, and only reserving path points on the boundary of the remaining original grid; s3, performing conventional segment-by-segment iteration on the thinned grid, changing the direction of the boundary of the thinned grid, and changing the inflection path into a path meeting the Snell's law by changing a spatial discretization mode; and S4, gradually encrypting the thinning grid, repeating the step S3 for each encryption until the current thinning level is reduced to 0, and then carrying out the last time of conventional segment-by-segment iteration. According to the method, the problems that a conventional segment-by-segment