Support Image, 2D bounding box and segmentation as Arrow extension types

[eddyxu]

Problem Statement

To support rich semantic types, we can utilize Arrow's extension types. It will help us to reach to the feature parity to Rikai storage format.

Questions to answers:

• Do we want to only implement the data type in Lance?
• How should we consolidate with Rikai's type system?
• How to make the type system extensible?
• Or should we keep the extension types out of the lance data format. Lance just accepts extension types?

Desired Behavior

• Support Image type
• Bounding Box
• Segmentation
• Label?
• These objects can be SerDe transparently without manually providing schema.

[changhiskhan]

does “only implement the data type in lance” mean whether to implement arrow extension type? Or whether to implement python classes in pylance (like in rikai)?

[changhiskhan]

• Start with just image/box2d
• Separate dir and branch in lance
• Figure out whether to create separate repo/project for this
• How to not confuse early adopters but also not turn lance into a kitchen sink project like Rikai

[changhiskhan]

going to make a separate issue for Segmentation etc