Support UInt8 with Connected Components (Auto and Manual)

[ConnorNoddin]

Sometimes, my segmentation has less than 256 components. In this example, connected_components() currently defaults to the uint16 datatype. However, all unique labels for my components would fit in the uint8 datatype. Consequently, I use twice as much peak RAM as is needed.

[william-silversmith]

Hi Connor,

The reason uint8 is not supported is because of its very limited utility. The final labels in a uint8 volume might be fewer than 256, but the provisional labels that are assigned during the first pass are typically 8-10x more numerous or more so it doesn't take much for this to be exceeded.

Can you show me a sample of the kind of data you think would benefit from uint8?

For what it's worth, there are more complex algorithms out there that can "reuse" provisional labels and make memory usage more efficient, though if they run out of labels part-way through, it has to dynamically resize to uint16.

A flood-fill algorithm will be even more efficient with the number of labels, but will be significantly slower.