Figure 20

ρ _i versus z _w graph and m _h versus z _w graph for upright plane unwrapping. For upright plane unwrapping, ρ _i is rather “evenly distributed ^{′ ′} across z _w as illustrated by the solid line plot (Both are in pixels). Therefore, panoramic unwrapping suffer less quality degradation due to mapping along ρ-axis. The overlapping dashed line plot illustrates the gradient of incident ray, m _j , involved. Since m _j changes sign at one point, the constraint for Equation 10 is more convenient when z _w is chosen.