README.md

---
library_name: pytorch
license: bsd-3-clause
tags:
- android
pipeline_tag: unconditional-image-generation

---

![](https://qaihub-public-assets.s3.us-west-2.amazonaws.com/qai-hub-models/models/simple_bev_cam/web-assets/model_demo.png)

# Simple-Bev: Optimized for Mobile Deployment
## Construct a bird’s eye view from sensors mounted on a vehicle


Simple_bev is a machine learning model for generating a birds eye view represenation from the sensors(cameras) mounted on a vehicle. It uses the ResNet-101 as the backbone and segnet as a segmentation model for specific use cases.

This model is an implementation of Simple-Bev found [here](https://github.com/aharley/simple_bev/blob/main/nets/segnet.py).


This repository provides scripts to run Simple-Bev on Qualcomm® devices.
More details on model performance across various devices, can be found
[here](https://aihub.qualcomm.com/models/simple_bev_cam).


### Model Details

- **Model Type:** Image generation
- **Model Stats:**
  - Model checkpoint: model-000025000.pth
  - Input resolution: 448 x 800
  - Number of parameters: 42M
  - Model size: 505 MB

| Model | Device | Chipset | Target Runtime | Inference Time (ms) | Peak Memory Range (MB) | Precision | Primary Compute Unit | Target Model
|---|---|---|---|---|---|---|---|---|
| Simple-Bev | Snapdragon 8 Elite QRD | Snapdragon® 8 Elite | TFLITE | 1533.805 ms | 1235 - 1552 MB | FP32 | CPU | [Simple-Bev.tflite](https://huggingface.co/qualcomm/Simple-Bev/blob/main/Simple-Bev.tflite) |
| Simple-Bev | SA8295P ADP | SA8295P | TFLITE | 1908.015 ms | 1249 - 1560 MB | FP32 | CPU | [Simple-Bev.tflite](https://huggingface.co/qualcomm/Simple-Bev/blob/main/Simple-Bev.tflite) |
| Simple-Bev | SA8775P ADP | SA8775P | TFLITE | 3593.07 ms | 1249 - 1546 MB | FP32 | CPU | [Simple-Bev.tflite](https://huggingface.co/qualcomm/Simple-Bev/blob/main/Simple-Bev.tflite) |
| Simple-Bev | QCS9075 (Proxy) | QCS9075 Proxy | TFLITE | 3593.07 ms | 1249 - 1546 MB | FP32 | CPU | [Simple-Bev.tflite](https://huggingface.co/qualcomm/Simple-Bev/blob/main/Simple-Bev.tflite) |




## Installation


Install the package via pip:
```bash
pip install qai-hub-models
```


## Configure Qualcomm® AI Hub to run this model on a cloud-hosted device

Sign-in to [Qualcomm® AI Hub](https://app.aihub.qualcomm.com/) with your
Qualcomm® ID. Once signed in navigate to `Account -> Settings -> API Token`.

With this API token, you can configure your client to run models on the cloud
hosted devices.
```bash
qai-hub configure --api_token API_TOKEN
```
Navigate to [docs](https://app.aihub.qualcomm.com/docs/) for more information.



## Demo off target

The package contains a simple end-to-end demo that downloads pre-trained
weights and runs this model on a sample input.

```bash
python -m qai_hub_models.models.simple_bev_cam.demo
```

The above demo runs a reference implementation of pre-processing, model
inference, and post processing.

**NOTE**: If you want running in a Jupyter Notebook or Google Colab like
environment, please add the following to your cell (instead of the above).
```
%run -m qai_hub_models.models.simple_bev_cam.demo
```


### Run model on a cloud-hosted device

In addition to the demo, you can also run the model on a cloud-hosted Qualcomm®
device. This script does the following:
* Performance check on-device on a cloud-hosted device
* Downloads compiled assets that can be deployed on-device for Android.
* Accuracy check between PyTorch and on-device outputs.

```bash
python -m qai_hub_models.models.simple_bev_cam.export
```
```
Profiling Results
------------------------------------------------------------
Simple-Bev
Device                          : Snapdragon 8 Elite QRD (15)
Runtime                         : TFLITE                     
Estimated inference time (ms)   : 1533.8                     
Estimated peak memory usage (MB): [1235, 1552]               
Total # Ops                     : 397                        
Compute Unit(s)                 : GPU (191 ops) CPU (206 ops)
```


## How does this work?

This [export script](https://aihub.qualcomm.com/models/simple_bev_cam/qai_hub_models/models/Simple-Bev/export.py)
leverages [Qualcomm® AI Hub](https://aihub.qualcomm.com/) to optimize, validate, and deploy this model
on-device. Lets go through each step below in detail:

Step 1: **Compile model for on-device deployment**

To compile a PyTorch model for on-device deployment, we first trace the model
in memory using the `jit.trace` and then call the `submit_compile_job` API.

```python
import torch

import qai_hub as hub
from qai_hub_models.models.simple_bev_cam import Model

# Load the model
torch_model = Model.from_pretrained()

# Device
device = hub.Device("Samsung Galaxy S24")

# Trace model
input_shape = torch_model.get_input_spec()
sample_inputs = torch_model.sample_inputs()

pt_model = torch.jit.trace(torch_model, [torch.tensor(data[0]) for _, data in sample_inputs.items()])

# Compile model on a specific device
compile_job = hub.submit_compile_job(
    model=pt_model,
    device=device,
    input_specs=torch_model.get_input_spec(),
)

# Get target model to run on-device
target_model = compile_job.get_target_model()

```


Step 2: **Performance profiling on cloud-hosted device**

After compiling models from step 1. Models can be profiled model on-device using the
`target_model`. Note that this scripts runs the model on a device automatically
provisioned in the cloud.  Once the job is submitted, you can navigate to a
provided job URL to view a variety of on-device performance metrics.
```python
profile_job = hub.submit_profile_job(
    model=target_model,
    device=device,
)
        
```

Step 3: **Verify on-device accuracy**

To verify the accuracy of the model on-device, you can run on-device inference
on sample input data on the same cloud hosted device.
```python
input_data = torch_model.sample_inputs()
inference_job = hub.submit_inference_job(
    model=target_model,
    device=device,
    inputs=input_data,
)
    on_device_output = inference_job.download_output_data()

```
With the output of the model, you can compute like PSNR, relative errors or
spot check the output with expected output.

**Note**: This on-device profiling and inference requires access to Qualcomm®
AI Hub. [Sign up for access](https://myaccount.qualcomm.com/signup).




## Deploying compiled model to Android


The models can be deployed using multiple runtimes:
- TensorFlow Lite (`.tflite` export): [This
  tutorial](https://www.tensorflow.org/lite/android/quickstart) provides a
  guide to deploy the .tflite model in an Android application.


- QNN (`.so` export ): This [sample
  app](https://docs.qualcomm.com/bundle/publicresource/topics/80-63442-50/sample_app.html)
provides instructions on how to use the `.so` shared library  in an Android application.


## View on Qualcomm® AI Hub
Get more details on Simple-Bev's performance across various devices [here](https://aihub.qualcomm.com/models/simple_bev_cam).
Explore all available models on [Qualcomm® AI Hub](https://aihub.qualcomm.com/)


## License
* The license for the original implementation of Simple-Bev can be found
  [here](https://github.com/aharley/simple_bev/blob/main/LICENSE).
* The license for the compiled assets for on-device deployment can be found [here](https://qaihub-public-assets.s3.us-west-2.amazonaws.com/qai-hub-models/Qualcomm+AI+Hub+Proprietary+License.pdf)



## References
* [Simple-BEV: What Really Matters for Multi-Sensor BEV Perception?](https://arxiv.org/abs/2206.07959)
* [Source Model Implementation](https://github.com/aharley/simple_bev/blob/main/nets/segnet.py)



## Community
* Join [our AI Hub Slack community](https://aihub.qualcomm.com/community/slack) to collaborate, post questions and learn more about on-device AI.
* For questions or feedback please [reach out to us](mailto:[email protected]).