YOLOv2 in PyTorch

NOTE: This project is no longer maintained and may not compatible with the newest pytorch (after 0.4.0).

This is a PyTorch implementation of YOLOv2. This project is mainly based on darkflow and darknet.

I used a Cython extension for postprocessing and multiprocessing.Pool for image preprocessing. Testing an image in VOC2007 costs about 13~20ms.

For details about YOLO and YOLOv2 please refer to their project page and the paper: YOLO9000: Better, Faster, Stronger by Joseph Redmon and Ali Farhadi.

NOTE 1: This is still an experimental project. VOC07 test mAP is about 0.71 (trained on VOC07+12 trainval, reported by @cory8249). See issue1 and issue23 for more details about training.

NOTE 2: I recommend to write your own dataloader using torch.utils.data.Dataset since multiprocessing.Pool.imap won’t stop even there is no enough memory space. An example of dataloader for VOCDataset: issue71.

NOTE 3: Upgrade to PyTorch 0.4: https://github.com/longcw/yolo2-pytorch/issues/59

Installation and demo

Clone this repository

git clone [email protected]:longcw/yolo2-pytorch.git

Build the reorg layer (tf.extract_image_patches)
```
cd yolo2-pytorch
./make.sh
```
Download the trained model yolo-voc.weights.h5 and set the model path in demo.py
Run demo python demo.py.

Training YOLOv2

You can train YOLO2 on any dataset. Here we train it on VOC2007/2012.

Download the training, validation, test data and VOCdevkit

wget http://host.robots.ox.ac.uk/pascal/VOC/voc2007/VOCtrainval_06-Nov-2007.tar
wget http://host.robots.ox.ac.uk/pascal/VOC/voc2007/VOCtest_06-Nov-2007.tar
wget http://host.robots.ox.ac.uk/pascal/VOC/voc2007/VOCdevkit_08-Jun-2007.tar

Extract all of these tars into one directory named VOCdevkit

tar xvf VOCtrainval_06-Nov-2007.tar
tar xvf VOCtest_06-Nov-2007.tar
tar xvf VOCdevkit_08-Jun-2007.tar

It should have this basic structure

$VOCdevkit/                           # development kit
$VOCdevkit/VOCcode/                   # VOC utility code
$VOCdevkit/VOC2007                    # image sets, annotations, etc.
# ... and several other directories ...

Since the program loading the data in yolo2-pytorch/data by default, you can set the data path as following.
```
cd yolo2-pytorch
mkdir data
cd data
ln -s $VOCdevkit VOCdevkit2007
```
Download the pretrained darknet19 model and set the path in yolo2-pytorch/cfgs/exps/darknet19_exp1.py.
(optional) Training with TensorBoard.

To use the TensorBoard, set use_tensorboard = True in yolo2-pytorch/cfgs/config.py and install TensorboardX (https://github.com/lanpa/tensorboard-pytorch). Tensorboard log will be saved in training/runs.
Run the training program: python train.py.

Evaluation

Set the path of the trained_model in yolo2-pytorch/cfgs/config.py.

cd faster_rcnn_pytorch
mkdir output
python test.py

Training on your own data

The forward pass requires that you supply 4 arguments to the network:

im_data – image data.
- This should be in the format C x H x W, where C corresponds to the color channels of the image and H and W are the height and width respectively.
- Color channels should be in RGB format.
- Use the imcv2_recolor function provided in utils/im_transform.py to preprocess your image. Also, make sure that images have been resized to 416 x 416 pixels
gt_boxes – A list of numpy arrays, where each one is of size N x 4, where N is the number of features in the image. The four values in each row should correspond to x_bottom_left, y_bottom_left, x_top_right, and y_top_right.
gt_classes – A list of numpy arrays, where each array contains an integer value corresponding to the class of each bounding box provided in gt_boxes
dontcare – a list of lists