from ..registry import BACKBONES
from .mobilenet_v2 import InvertedResidual, MobileNetV2
from .resnet_tsm import TemporalShift
[docs]@BACKBONES.register_module()
class MobileNetV2TSM(MobileNetV2):
"""MobileNetV2 backbone for TSM.
Args:
num_segments (int): Number of frame segments. Default: 8.
is_shift (bool): Whether to make temporal shift in reset layers.
Default: True.
shift_div (int): Number of div for shift. Default: 8.
**kwargs (keyword arguments, optional): Arguments for MobilNetV2.
"""
def __init__(self, num_segments=8, is_shift=True, shift_div=8, **kwargs):
super().__init__(**kwargs)
self.num_segments = num_segments
self.is_shift = is_shift
self.shift_div = shift_div
[docs] def make_temporal_shift(self):
"""Make temporal shift for some layers."""
for m in self.modules():
if isinstance(m, InvertedResidual) and \
len(m.conv) == 3 and m.use_res_connect:
m.conv[0] = TemporalShift(
m.conv[0],
num_segments=self.num_segments,
shift_div=self.shift_div,
)
[docs] def init_weights(self):
"""Initiate the parameters either from existing checkpoint or from
scratch."""
super().init_weights()
if self.is_shift:
self.make_temporal_shift()