-h | Help, prints usage message. |
-o | Output file name. |
-a | Add the object's grey values. |
-d | Divide the grey values of the 1st object by those of the 2nd. |
-g | Vector magnitude of horizontal and vertical component objects. |
-i | Dither values when setting range. |
-l | Compute the modulus of the grey values of the 1st object wrt those of the 2nd. |
-m | Multiply the object's grey values. |
-s | Subtract the grey values of the 2nd object from those of the 1st. |
-n | Normalises the output object to the range of the input objects. |
-N | Normalises the output objects to the range [0-255]. |
-O | Overwrite option (only useful for debugging). |