Point operations can be accessed using the Modify | Pixels | Point menu item. These tools modify pixel data individually.
Scale changes pixel values by a multiplicative scale factor. Scale factors must be non-zero.
Erode reduces the number of valid pixels based on specified criteria. This is normally used to reduce noisy pixels. For furthur information see Erosion.
Mask specifies regions of pixel values to include or exclude from calculation. Use the Apply Mask menu item or button to make masked region pixels non-valid. The Save Mask menu item or button will allow the currently defined mask to be saved to a file. Load Mask or the button will append a previously stored mask to the currently defined mask. Toggling the Display mask toolbar menu item will make the mask toolbar visible or remove it from the workspace. See Masking.