For greyscale calibration, look under "Equal Energy Windows".
"These patterns are designed for measuring with a colorimeter, light meter, or spectroradiometer as part of a gray scale calibration by a trained calibrator. They are designed so the total amount of light being produced by the display is unchanged from pattern to pattern. As the level in the center changes, the concentric bands around the edge change to compensate, keeping the overall light output and power draw constant even on notoriously tricky displays like plasma panels."
For colour calibration, look under "Equal Energy Gamut".
"These patterns are designed for measuring with a colorimeter or spectroradiometer as part of a color gamut calibration by a trained calibrator. They are designed so the total amount of light being produced by the display in all color channels is unchanged from pattern to pattern. As the level in the center changes, the concentric bands around the edge change to compensate, keeping the overall light output and power draw constant for each color channel even on notoriously tricky displays like plasma panels."