HP sv6 - Manual (Page 94)

projector calibration targets
how to use projector calibration targets
Chapter 4 94
Figure 4-2 hp_line.pm 64X64 grid lines (tiled example shown)
64 x 64 grids for horizontal and vertical convergence.
Figure 4-3 hp_gray.pm gray scale (tiled example shown)
16 step gray scale on horizontal axis with 0-255 indicators to compute
brightness.