How to use the SageMaker AI Object Detection - TensorFlow algorithm

You can use Object Detection - TensorFlow as an Amazon SageMaker AI built-in algorithm. The following section describes how to use Object Detection - TensorFlow with the SageMaker AI Python SDK. For information on how to use Object Detection - TensorFlow from the Amazon SageMaker Studio Classic UI, see SageMaker JumpStart pretrained models.

The Object Detection - TensorFlow algorithm supports transfer learning using any of the compatible pretrained TensorFlow models. For a list of all available pretrained models, see TensorFlow Models. Every pretrained model has a unique model_id. The following example uses ResNet50 (model_id: tensorflow-od1-ssd-resnet50-v1-fpn-640x640-coco17-tpu-8) to fine-tune on a custom dataset. The pretrained models are all pre-downloaded from the TensorFlow Hub and stored in Amazon S3 buckets so that training jobs can run in network isolation. Use these pre-generated model training artifacts to construct a SageMaker AI Estimator.

First, retrieve the Docker image URI, training script URI, and pretrained model URI. Then, change the hyperparameters as you see fit. You can see a Python dictionary of all available hyperparameters and their default values with hyperparameters.retrieve_default. For more information, see Object Detection - TensorFlow Hyperparameters. Use these values to construct a SageMaker AI Estimator.

This example uses the PennFudanPed dataset, which contains images of pedestriants in the street. We pre-downloaded the dataset and made it available with Amazon S3. To fine-tune your model, call .fit using the Amazon S3 location of your training dataset.

from sagemaker import image_uris, model_uris, script_uris, hyperparameters
from sagemaker.estimator import Estimator

model_id, model_version = "tensorflow-od1-ssd-resnet50-v1-fpn-640x640-coco17-tpu-8", "*"
training_instance_type = "ml.p3.2xlarge"

# Retrieve the Docker image
train_image_uri = image_uris.retrieve(model_id=model_id,model_version=model_version,image_scope="training",instance_type=training_instance_type,region=None,framework=None)

# Retrieve the training script
train_source_uri = script_uris.retrieve(model_id=model_id, model_version=model_version, script_scope="training")

# Retrieve the pretrained model tarball for transfer learning
train_model_uri = model_uris.retrieve(model_id=model_id, model_version=model_version, model_scope="training")

# Retrieve the default hyperparameters for fine-tuning the model
hyperparameters = hyperparameters.retrieve_default(model_id=model_id, model_version=model_version)

# [Optional] Override default hyperparameters with custom values
hyperparameters["epochs"] = "5"

# Sample training data is available in this bucket
training_data_bucket = f"jumpstart-cache-prod-{aws_region}"
training_data_prefix = "training-datasets/PennFudanPed_COCO_format/"

training_dataset_s3_path = f"s3://{training_data_bucket}/{training_data_prefix}"

output_bucket = sess.default_bucket()
output_prefix = "jumpstart-example-od-training"
s3_output_location = f"s3://{output_bucket}/{output_prefix}/output"

# Create an Estimator instance
tf_od_estimator = Estimator(
    role=aws_role,
    image_uri=train_image_uri,
    source_dir=train_source_uri,
    model_uri=train_model_uri,
    entry_point="transfer_learning.py",
    instance_count=1,
    instance_type=training_instance_type,
    max_run=360000,
    hyperparameters=hyperparameters,
    output_path=s3_output_location,
)

# Launch a training job
tf_od_estimator.fit({"training": training_dataset_s3_path}, logs=True)

For more information about how to use the SageMaker AI Object Detection - TensorFlow algorithm for transfer learning on a custom dataset, see the Introduction to SageMaker TensorFlow - Object Detection notebook.