add box selector

[Can-Zhao]

Signed-off-by: Can Zhao [email protected]

Fixes #3576. Fix #4416.

Description

split box selection in detection inference out into BoxSelector
make box coder more general (not used in retinanet, but might be used in faster rcnn)
add batch nms

Status

Ready/Work in progress/Hold

Types of changes

• Non-breaking change (fix or new feature that would not break existing functionality).
• Breaking change (fix or new feature that would cause existing functionality to change).
• New tests added to cover the changes.
• Integration tests passed locally by running ./runtests.sh -f -u --net --coverage.
• Quick tests passed locally by running ./runtests.sh --quick --unittests --disttests.
• In-line docstrings updated.
• Documentation updated, tested make html command in the docs/ folder.

[wyli]

utilities for selecting candidate boxes

[wyli]

/build

[wyli]

/build

[Nic-Ma]

/build