Skip to content

Open In Colab

Getting Started with Keypoint Detection using IceVision

Introduction

This tutorial walk you through the different steps of training the biwi dataset. the IceVision Framework is an agnostic framework. As an illustration, we will train our model using both the fastai library, and pytorch-lightning libraries.

For more information about how the biwi dataset as well as its corresponding parser check out the biwi folder in icedata.

Installing IceVision and IceData

# IceVision - IceData - MMDetection - YOLO v5 Installation
!wget https://raw.githubusercontent.com/airctic/icevision/master/install_colab.sh
!chmod +x install_colab.sh && ./install_colab.sh

Imports

from icevision.all import *

Model

To create a model, we need to:

  • Choose one of the models supported by IceVision
  • Choose one of the backbones corresponding to a chosen model
  • Determine the number of the object classes: This will be done after parsing a dataset. Check out the Parsing Section

Choose a model and backbone

TorchVision

model_type = models.torchvision.keypoint_rcnn
backbone = model_type.backbones.resnet34_fpn()

Datasets : Biwi

Biwi dataset is tiny dataset that contains 200 images of 1 class Nose.

We will use icedata to download the dataset and get it with pre-defined transforms for training and validation.

Note: If you want a more challenging dataset take a look at OCHuman.

# Loading Data
data_dir = icedata.biwi.load_data()
train_ds, valid_ds = icedata.biwi.dataset(data_dir)

Displaying the same image with different transforms

Note:

Transforms are applied lazily, meaning they are only applied when we grab (get) an item. This means that, if you have augmentation (random) transforms, each time you get the same item from the dataset you will get a slightly different version of it.

samples = [train_ds[0] for _ in range(3)]
show_samples(samples, ncols=3)

png

DataLoader

# DataLoaders
train_dl = model_type.train_dl(train_ds, batch_size=8, num_workers=4, shuffle=True)
valid_dl = model_type.valid_dl(valid_ds, batch_size=8, num_workers=4, shuffle=False)
model_type.show_batch(first(valid_dl), ncols=4)

png

Model

Now that we determined the number of classes (num_classes) and number of keypoints (num_keypoints), we can create our model object.

# TODO: Better flow for train_ds
model = model_type.model(backbone=backbone, num_keypoints=1, num_classes=icedata.biwi.NUM_CLASSES) 

Metrics

Metrics for keypoint are a work in progress

# metrics = [COCOMetric(metric_type=COCOMetricType.keypoint)]

Training

IceVision is an agnostic framework meaning it can be plugged to other DL framework such as fastai2, and pytorch-lightning.

You could also plug to oth DL framework using your own custom code.

Training using fastai

learn = model_type.fastai.learner(dls=[train_dl, valid_dl], model=model)
learn.lr_find()
SuggestedLRs(lr_min=8.317637839354575e-05, lr_steep=0.00010964782268274575)

png

learn.fine_tune(10, 3e-5, freeze_epochs=1)
epoch train_loss valid_loss time
0 8.645806 7.013292 00:28
epoch train_loss valid_loss time
0 6.684147 6.487582 00:26
1 6.277197 5.731036 00:26
2 5.836541 5.114465 00:26
3 5.408250 4.583161 00:20
4 4.996461 4.225419 00:23
5 4.657006 3.987719 00:21
6 4.335581 3.832931 00:20
7 4.114164 3.862228 00:20
8 3.902603 3.697594 00:20
9 3.768973 3.694008 00:21

Training using Lightning

class LightModel(model_type.lightning.ModelAdapter):
    def configure_optimizers(self):
        return SGD(self.parameters(), lr=3e-5)

light_model = LightModel(model)
trainer = pl.Trainer(max_epochs=2, gpus=1)
trainer.fit(light_model, train_dl, valid_dl)

Show Results

model_type.show_results(model, valid_ds, detection_threshold=.5)

png

Inference

Predicting a batch of images

Instead of predicting a whole list of images at one, we can process small batches at the time: This option is more memory efficient.

NOTE: For a more detailed look at inference check out the inference tutorial

infer_dl = model_type.infer_dl(valid_ds, batch_size=4, shuffle=False)
preds = model_type.predict_from_dl(model, infer_dl, keep_images=True)
show_preds(preds=preds[:4])

png

Happy Learning!

If you need any assistance, feel free to join our forum.