  Deep SORT\cite{wojke2017simple} is a tracking-by-detetion approach to
multiple object tracking with a detector and a RE-ID model.
  Both separately training and inference with the two model is time-comsuming.
  In this paper, we unify the detector and RE-ID model into an end-to-end
network, by adding an additional track branch for tracking in Faster RCNN
architecture. With a unified network, we are able to train the whole model
end-to-end with multi loss, which has shown much benefit in other recent works.
  The RE-ID model in Deep SORT needs to use deep CNNs to extract feature map
from detected object images, However, track branch in our proposed network
straight make use of
  the RoI feature vector in Faster RCNN baseline, which reduced the amount of
calculation.
  Since the single image lacks the same object which is necessary when we use
the triplet loss to optimizer the track branch, we concatenate the neighbouring
frames in a video to construct our training dataset.
  We have trained and evaluated our model on AIC19 vehicle tracking dataset,
experiment shows that our model with resnet101 backbone can achieve 57.79 \%
mAP and track vehicle well.
