Questions and postings pertaining to the usage of ImageMagick regardless of the interface. This includes the command-line utilities, as well as the C and C++ APIs. Usage questions are like "How do I use ImageMagick to create drop shadows?".
The define for mean color only says that the output should represent the mean color of the region. If you do not use that, then the output image gray levels would be the id numbers for each region.
By using -define connected-components:area-threshold=64, you are telling connected components to remove all regions that have an area smaller than 64 pixels.
I am not sure what you are trying to do. Please clarify further.