SyntheOcc

SyntheOcc: Synthesize Geometric-Controlled Street View Images through 3D Semantic MPIs
Leheng Li, Weichao Qiu, Yingjie Cai, Xu Yan, Qing Lian, Bingbing Liu, Ying-Cong Chen

SyntheOcc is a project focused on synthesizing image data under geometry control (occupancy voxel). This repository provides tools and scripts to process, train, and generate synthetic image data in the nuScenes dataset, using occupancy control.

Project Page

Code: https://github.com/EnVision-Research/SyntheOcc

Installation
Prepare Dataset
Prepare Checkpoint
Train
Inference

Installation

To get started with SyntheOcc, follow these steps:

Clone the repository:

git clone https://github.com/Len-Li/SyntheOcc.git
cd SyntheOcc

Set up a environment :

pip install torch torchvision transformers
pip install diffusers==0.26.0.dev0 
# We use a old version of diffusers, please take care of it.

Prepare Dataset

To use SyntheOcc, follow the steps below:

Download the NuScenes dataset:
- Register and download the dataset from the NuScenes website.
- Download the train/val pickle files from OpenOccupancy and put them in data/nuscenes folder.
After preparation, you will be able to see the following directory structure:
```
SyntheOcc/
├── data/
│   ├── nuscenes/
│   │   ├── samples/
│   │   ├── sweeps/
|   |   ├── v1.0-trainval/
|   |   ├── nuscenes_occ_infos_train.pkl
|   |   ├── nuscenes_occ_infos_val.pkl
```
Download occupancy annotation from SurroundOcc

You need to generate the high resolution 0.2m occupancy from mesh vertices and put them in data/nuscenes folder.

You can also download the 0.5m occupancy. The precision may be limited compared with 0.2m.
Run the script to convert occupancy to 3D semantic multiplane images:
```
torchrun utils/gen_mtp.py
```
It will generate the 3D semantic MPI and save them in data/nuscenes/samples_syntheocc_surocc/ folder.

Prepare Checkpoint

Our model is based on stable-diffusion-v2-1. Please put them at ./SyntheOcc/ckp/.

Our checkpoint of SyntheOcc is released in huggingface. If you want to use our model to run inference. Please also put them at ./SyntheOcc/ckp/.

Train

bash train.sh

The details of the script are as follows:

export WANDB_DISABLED=True
export HF_HUB_OFFLINE=True

export MODEL_DIR="./ckp/stable-diffusion-v2-1"

export EXP_NAME="train_syntheocc"
export OUTPUT_DIR="./ckp/$EXP_NAME"
export SAVE_IMG_DIR="vis_dir/$EXP_NAME/samples"
export DATA_USED="samples_syntheocc_surocc"

accelerate launch --gpu_ids 0, --num_processes 1  --main_process_port 3226  train.py \
    --pretrained_model_name_or_path=$MODEL_DIR \
    --output_dir=$OUTPUT_DIR \
    --width=800 \
    --height=448 \
    --learning_rate=2e-5 \
    --num_train_epochs=6 \
    --train_batch_size=1 \
    --mixed_precision="fp16" \
    --num_validation_images=2 \
    --validation_steps=1000 \
    --checkpointing_steps=5000 \
    --checkpoints_total_limit=10 \
    --ctrl_channel=257 \
    --enable_xformers_memory_efficient_attention \
    --report_to='wandb' \
    --use_cbgs=True \
    --mtp_path='samples_syntheocc_surocc' \
    --resume_from_checkpoint="latest"

The training process will take 1~2 days to complete, depending on the hardware. We use a fixed batchsize=1, image resolution = (800, 448), which will take 25GB memory for each GPU.

Inference

bash infer.sh

You will find generated images at ./ckp/$EXP_NAME/samples. The image is shown as follows:

Acknowledgment

Additionally, we express our gratitude to the authors of the following opensource projects:

SurroundOcc (Occupancy annotation)
OpenOccupancy (Occupancy annotation)
MagicDrive (Cross-view and cross-frame attention implementation)
Diffusers controlnet example (Diffusion model implementation)

BibTeX

@inproceedings{li2024SyntheOcc,
              title={SyntheOcc: Synthesize Geometric Controlled Street View Images through 3D Semantic MPIs},
              author={Li, Leheng and Qiu, Weichao and Chen, Ying-Cong et.al.},
              booktitle={arxiv preprint},
              year={2024}
            }

This project is licensed under the MIT License - see the LICENSE file for details.

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SyntheOcc