detection

Object Detection Models on TensorFlow 2.0

Note: The repo is still under construction. More features and instructions will be added soon.

Prerequsite

To get started, make sure to use Tensorflow 2.1+ on Google Cloud. Also here are a few package you need to install to get started:

sudo apt-get install -y python-tk && \
pip install Cython matplotlib opencv-python-headless pyyaml Pillow && \
pip install 'git+https://github.com/cocodataset/cocoapi#egg=pycocotools&subdirectory=PythonAPI'

Next, download the code from TensorFlow models github repository or use the pre-installed Google Cloud VM.

git clone https://github.com/tensorflow/models.git

Train RetinaNet on TPU

Train a vanilla ResNet-50 based RetinaNet.

TPU_NAME="<your GCP TPU name>"
MODEL_DIR="<path to the directory to store model files>"
RESNET_CHECKPOINT="<path to the pre-trained Resnet-50 checkpoint>"
TRAIN_FILE_PATTERN="<path to the TFRecord training data>"
EVAL_FILE_PATTERN="<path to the TFRecord validation data>"
VAL_JSON_FILE="<path to the validation annotation JSON file>"
python ~/models/official/vision/detection/main.py \
  --strategy_type=tpu \
  --tpu="${TPU_NAME?}" \
  --model_dir="${MODEL_DIR?}" \
  --mode=train \
  --params_override="{ type: retinanet, train: { checkpoint: { path: ${RESNET_CHECKPOINT?}, prefix: resnet50/ }, train_file_pattern: ${TRAIN_FILE_PATTERN?} }, eval: { val_json_file: ${VAL_JSON_FILE?}, eval_file_pattern: ${EVAL_FILE_PATTERN?} } }"

Train a custom RetinaNet using the config file.

First, create a YAML config file, e.g. my_retinanet.yaml. This file specifies the parameters to be overridden, which should at least include the following fields.

# my_retinanet.yaml
type: 'retinanet'
train:
  train_file_pattern: <path to the TFRecord training data>
eval:
  eval_file_pattern: <path to the TFRecord validation data>
  val_json_file: <path to the validation annotation JSON file>

Once the YAML config file is created, you can launch the training using the following command.

TPU_NAME="<your GCP TPU name>"
MODEL_DIR="<path to the directory to store model files>"
python ~/models/official/vision/detection/main.py \
  --strategy_type=tpu \
  --tpu="${TPU_NAME?}" \
  --model_dir="${MODEL_DIR?}" \
  --mode=train \
  --config_file="my_retinanet.yaml"

Train RetinaNet on GPU

Training on GPU is similar to that on TPU. The major change is the strategy type (use "mirrored" for multiple GPU and "one_device" for single GPU).

Multi-GPUs example (assuming there are 8GPU connected to the host):

MODEL_DIR="<path to the directory to store model files>"
python3 ~/models/official/vision/detection/main.py \
  --strategy_type=mirrored \
  --num_gpus=8 \
  --model_dir="${MODEL_DIR?}" \
  --mode=train \
  --config_file="my_retinanet.yaml"

MODEL_DIR="<path to the directory to store model files>"
python3 ~/models/official/vision/detection/main.py \
  --strategy_type=one_device \
  --num_gpus=1 \
  --model_dir="${MODEL_DIR?}" \
  --mode=train \
  --config_file="my_retinanet.yaml"

An example with inline configuration (YAML or JSON format):

python3 ~/models/official/vision/detection/main.py \
  --model_dir=<model folder> \
  --strategy_type=one_device \
  --num_gpus=1 \
  --mode=train \
  --params_override="eval:
 eval_file_pattern: <Eval TFRecord file pattern>
 batch_size: 8
 val_json_file: <COCO format groundtruth JSON file>
predict:
 predict_batch_size: 8
architecture:
 use_bfloat16: False
retinanet_parser:
 use_bfloat16: Flase
train:
 total_steps: 1
 batch_size: 8
 train_file_pattern: <Eval TFRecord file pattern>
use_tpu: False
"

Note: The JSON groundtruth file is useful for COCO dataset and can be downloaded from the COCO website. For custom dataset, it is unncessary because the groundtruth can be included in the TFRecord files.

References

1. Focal Loss for Dense Object Detection. Tsung-Yi Lin, Priya Goyal, Ross Girshick, Kaiming He, and Piotr Dollár. IEEE International Conference on Computer Vision (ICCV), 2017.