When executing this command, a parameter window appears in which you can specify the type of surface to be subtracted: Linear - for subtracting the general slope (plane) or Parabolic - for subtracting a second-order surface:

If the source file contains several images, they can be processed in the same way, subtracting the same surface, or independently of each other. The processing method is determined by the Sub-image processing parameter :

Separately - for each image contained in the file, the average surface is calculated, determined by the least squares method for a specific image;

By active - the surface is calculated for the active image and subtracted from all;

By all - average surfaces are calculated for all sub-images and averaged.

If there is a check mark next to the Remove constant component field , then the total displacement of the entire surface relative to zero is removed.

It is important to remember that if you select a small fragment of the image before calling the Align command , then only the values ​​of the points in the selection will be used when calculating the surface equation. In this case, the constructed surface will be subtracted from the entire image.

In a similar way, one can subtract a surface constructed using the least squares method using several points marked with labels on the image.