Using the Blob Analysis module, you can also calculate the moments used to find the center of gravity, as well as other grayscale and binary moments. The MblobSelectMoment() function allows you to add any moment to the feature list, whereas MblobSelectFeature() allows you to add only the more common moments (for example, M_MOMENT_X0_Y2). These common moments are calculated faster if selected by MblobSelectFeature().
You can calculate either central or ordinary moments. Central moments use coordinates that are relative to the center of gravity of the blob, and therefore are independent of a blob's position within the image, whereas, ordinary moments are affected by the blob position because they use coordinates relative to the top left corner of the image.