| comp_info | Informations about the components of an imabe object. |
| count_obj | Number of objects in a tuple. |
| equal_obj | Compare image objects regarding equality. |
| equal_region | Test whether the regions of two objects are identical. |
| obj_class | Name of the class of an imabe object. |
| obj_def | Test whether an object is already deleted. |
| obj_info | Information about the input image objects last used. |