Hand Detection Tutorial

This is a tutorial on how to train a 'hand detector' with TensorFlow object detection API. This README outlines how to set up everything and train the object detection model locally. You could refer to the following blog post for more detailed description about the steps within.

• Training a Hand Detector with TensorFlow Object Detection API
• Adapting the Hand Detector Tutorial to Your Own Data

Table of contents

• Setup
• Training
• Evaluating the trained model
• Testing the trained model with an image
• Deploying the trained model onto Jetson TX2

Setup

Just for reference, the code in this repository has been tested on a desktop PC with:

• NVIDIA GeForce GTX-1080Ti
• Ubuntu 16.04.5 LTS (x86_64)
• CUDA 9.2
• cuDNN 7.1.4
• TensorFlow 1.10.0

This tutorial uses python3 for training and testing the TensorFlow object detection models. Follow the steps below to set up the environment for training the models. Make sure tensorflow-gpu or tensorflow (python3 packages) has been installed on the system already.

1. Clone this repository.

   $ cd ~/project
   $ git clone https://github.com/jkjung-avt/hand-detection-tutorial.git
   $ cd hand-detection-tutorial

2. Install required python3 packages.

   $ sudo pip3 install -r requirements.txt

   In case you are having trouble with sudo, you can do pip3 install --user -r requirements.txt instead.

3. Run the installation script. Make sure the last step in the script, Running model_builder_test.py, finishes without error, before continuing on.

   $ ./install.sh

4. Download pretrained models from TensorFlow Object Detection Model Zoo.

   $ ./download_pretrained_models.sh

Training

1. Prepare the 'egohands' dataset.

   $ python3 prepare_egohands.py

   The prepare_egohands.py script downloads the 'egohands' dataset and convert its annotations to KITTI format. When finished, the following files should be present in the folder. Note there are totally 4,800 jpg images in the 'egohands' dataset.

   ./egohands_data.zip
   ./egohands
     ├── (egohands dataset unzipped)
     └── ......
   ./egohands_kitti_formatted
     ├── images
     │   ├── CARDS_COURTYARD_B_T_frame_0011.jpg
     │   ├── ......
     │   └── PUZZLE_OFFICE_T_S_frame_2697.jpg
     └── labels
         ├── CARDS_COURTYARD_B_T_frame_0011.txt
         ├── ......
         └── PUZZLE_OFFICE_T_S_frame_2697.txt
   

2. Create the TFRecord files (train/val) needed to train the object detection model. The create_tfrecords.py script would split the jpg images into 'train' (4,300) and 'val' (500) sets, and then generate data/egohands_train.tfrecord and data/egohands_val.tfrecord. This process might take a few minutes. The resulting TFRecord files are roughly 1.1GB and 132MB in size.

   $ ./create_tfrecords.sh

3. (Optional) Review and modify the model config file if necessary. For example, open the file configs/ssd_mobilenet_v1_egohands.config with an editor and do some editing.

4. Start training the model by invoking ./train.sh <model_name>. For example, to train the detector based on ssd_mobilenet_v1. Do this:

   $ ./train.sh ssd_mobilenet_v1_egohands

   The training is set to run for 20,000 iterations. It takes roughly 2 hours to finish on the desktop PC listed above.

   If you have multiple GPUs, you could specify which GPU to use for the training with the CUDA_VISIBLE_DEVICES environment variable. For example, the following command starts a training session for the faster_rcnn_inception_v2_egohands model on the 2nd GPU (GPU #1).

   $ CUDA_VISIBLE_DEVICES=1 ./train.sh faster_rcnn_inception_v2_egohands

5. Monitor the progress of training with TensorBoard, by executing tensorboard in another terminal.

   $ cd ~/project/hand-detection-tutorial
   $ tensorboard --logdir=ssd_mobilenet_v1_egohands

   Then open http://localhost:6006 with a browser locally. (You could also replace localhost with IP address of the training PC, and do the monitoring remotely.)

   

Evaluating the trained model

• The trained model could be evaluated by simply executing the ./eval.sh script. For example,

  # similar to train.sh, use 'CUDA_VISIBLE_DEVICES' to specify GPU
  $ ./eval.sh ssd_mobilenet_v1_egohands

  Here's an example output of the evaluation output. Among all the numbers, the author would pay most attention to the 'AP @ IoU=0.50' value (0.967).

    Average Precision  (AP) @[ IoU=0.50:0.95 | area=   all | maxDets=100 ] = 0.681
    Average Precision  (AP) @[ IoU=0.50      | area=   all | maxDets=100 ] = 0.967
    Average Precision  (AP) @[ IoU=0.75      | area=   all | maxDets=100 ] = 0.809
    Average Precision  (AP) @[ IoU=0.50:0.95 | area= small | maxDets=100 ] = 0.079
    Average Precision  (AP) @[ IoU=0.50:0.95 | area=medium | maxDets=100 ] = 0.313
    Average Precision  (AP) @[ IoU=0.50:0.95 | area= large | maxDets=100 ] = 0.717
    Average Recall     (AR) @[ IoU=0.50:0.95 | area=   all | maxDets=  1 ] = 0.258
    Average Recall     (AR) @[ IoU=0.50:0.95 | area=   all | maxDets= 10 ] = 0.736
    Average Recall     (AR) @[ IoU=0.50:0.95 | area=   all | maxDets=100 ] = 0.742
    Average Recall     (AR) @[ IoU=0.50:0.95 | area= small | maxDets=100 ] = 0.118
    Average Recall     (AR) @[ IoU=0.50:0.95 | area=medium | maxDets=100 ] = 0.466
    Average Recall     (AR) @[ IoU=0.50:0.95 | area= large | maxDets=100 ] = 0.774
  

  In addition, you could run tensorboard to inspect details of the evaluation. Note logdir points to the 'eval' subdirectory below.

  $ cd ~/project/hand-detection-tutorial
  $ tensorboard --logdir=ssd_mobilenet_v1_egohands_eval

  Again, open http://localhost:6006 or http://<IP.addr>:6006 with a browser. Click on the 'IMAGES' tab. You can then browse through all images in the validation set and check how well your trained model performs on those images.

  

Testing the trained model with an image

• This repo also includes scripts to test the trained model with your own image file. For example, the following commands would convert a trained ssdlite_mobilenet_v2_egohands model into a frozen graph (saved under model_exported/), and then use the graph to detect hands in data/jk-son-hands.jpg. The output image, with bounding boxes overlaid, would be saved as detection_output.jpg.

  $ CUDA_VISIBLE_DEVICES=0 ./export.sh ssdlite_mobilenet_v2_egohands
  $ CUDA_VISIBLE_DEVICES=0 ./detect_image.sh data/jk-son-hands.jpg 

  You can then check out the output image by, say,

  $ display detection_output.jpg

  

Deploying the trained model onto Jetson TX2/Nano

Please refer to the following GitHub repos and blog posts.

• Demo #3 ('ssd') of jkjung-avt/tensorrt_demos -> The trained 'ssd_mobilenet_v1_egohands' model could run as fast as ~31 frames per seconds (FPS) on Jetson Nano using 'trt_ssd_async.py'!
• jkjung-avt/tf_trt_models
• Deploying the Hand Detector onto Jetson TX2
• TensorFlow/TensorRT (TF-TRT) Revisited
• Testing TF-TRT Object Detectors on Jetson Nano