DenseNet-121: Optimized for Mobile Deployment

Imagenet classifier and general purpose backbone

Densenet is a machine learning model that can classify images from the Imagenet dataset. It can also be used as a backbone in building more complex models for specific use cases.

This model is an implementation of DenseNet-121 found here.

This repository provides scripts to run DenseNet-121 on Qualcomm® devices. More details on model performance across various devices, can be found here.

Model Details

Model Type: Image classification
Model Stats:
- Model checkpoint: Imagenet
- Input resolution: 224x224
- Number of parameters: 7.97M
- Model size: 30.5 MB

Model	Device	Chipset	Target Runtime	Inference Time (ms)	Peak Memory Range (MB)	Precision	Primary Compute Unit	Target Model
DenseNet-121	Samsung Galaxy S23	Snapdragon® 8 Gen 2	TFLITE	1.93 ms	0 - 2 MB	FP16	NPU	DenseNet-121.tflite
DenseNet-121	Samsung Galaxy S23	Snapdragon® 8 Gen 2	QNN	2.0 ms	0 - 9 MB	FP16	NPU	DenseNet-121.so
DenseNet-121	Samsung Galaxy S23	Snapdragon® 8 Gen 2	ONNX	1.843 ms	0 - 249 MB	FP16	NPU	DenseNet-121.onnx
DenseNet-121	Samsung Galaxy S24	Snapdragon® 8 Gen 3	TFLITE	1.287 ms	0 - 100 MB	FP16	NPU	DenseNet-121.tflite
DenseNet-121	Samsung Galaxy S24	Snapdragon® 8 Gen 3	QNN	1.332 ms	1 - 21 MB	FP16	NPU	DenseNet-121.so
DenseNet-121	Samsung Galaxy S24	Snapdragon® 8 Gen 3	ONNX	1.322 ms	0 - 107 MB	FP16	NPU	DenseNet-121.onnx
DenseNet-121	Snapdragon 8 Elite QRD	Snapdragon® 8 Elite	TFLITE	1.224 ms	0 - 26 MB	FP16	NPU	DenseNet-121.tflite
DenseNet-121	Snapdragon 8 Elite QRD	Snapdragon® 8 Elite	QNN	1.038 ms	0 - 18 MB	FP16	NPU	Use Export Script
DenseNet-121	Snapdragon 8 Elite QRD	Snapdragon® 8 Elite	ONNX	1.058 ms	0 - 31 MB	FP16	NPU	DenseNet-121.onnx
DenseNet-121	QCS8550 (Proxy)	QCS8550 Proxy	TFLITE	1.919 ms	0 - 2 MB	FP16	NPU	DenseNet-121.tflite
DenseNet-121	QCS8550 (Proxy)	QCS8550 Proxy	QNN	1.789 ms	1 - 2 MB	FP16	NPU	Use Export Script
DenseNet-121	SA8255 (Proxy)	SA8255P Proxy	TFLITE	1.924 ms	0 - 3 MB	FP16	NPU	DenseNet-121.tflite
DenseNet-121	SA8255 (Proxy)	SA8255P Proxy	QNN	1.802 ms	1 - 2 MB	FP16	NPU	Use Export Script
DenseNet-121	SA8775 (Proxy)	SA8775P Proxy	TFLITE	1.933 ms	0 - 2 MB	FP16	NPU	DenseNet-121.tflite
DenseNet-121	SA8775 (Proxy)	SA8775P Proxy	QNN	1.797 ms	1 - 2 MB	FP16	NPU	Use Export Script
DenseNet-121	SA8650 (Proxy)	SA8650P Proxy	TFLITE	1.922 ms	0 - 2 MB	FP16	NPU	DenseNet-121.tflite
DenseNet-121	SA8650 (Proxy)	SA8650P Proxy	QNN	1.792 ms	2 - 3 MB	FP16	NPU	Use Export Script
DenseNet-121	SA8295P ADP	SA8295P	TFLITE	3.317 ms	0 - 26 MB	FP16	NPU	DenseNet-121.tflite
DenseNet-121	SA8295P ADP	SA8295P	QNN	3.294 ms	0 - 6 MB	FP16	NPU	Use Export Script
DenseNet-121	QCS8450 (Proxy)	QCS8450 Proxy	TFLITE	2.601 ms	0 - 101 MB	FP16	NPU	DenseNet-121.tflite
DenseNet-121	QCS8450 (Proxy)	QCS8450 Proxy	QNN	2.687 ms	1 - 21 MB	FP16	NPU	Use Export Script
DenseNet-121	Snapdragon X Elite CRD	Snapdragon® X Elite	QNN	2.074 ms	1 - 1 MB	FP16	NPU	Use Export Script
DenseNet-121	Snapdragon X Elite CRD	Snapdragon® X Elite	ONNX	2.016 ms	18 - 18 MB	FP16	NPU	DenseNet-121.onnx

Installation

This model can be installed as a Python package via pip.

pip install qai-hub-models

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

Sign-in to Qualcomm® AI Hub 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.

qai-hub configure --api_token API_TOKEN

Navigate to 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.

python -m qai_hub_models.models.densenet121.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.densenet121.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.

python -m qai_hub_models.models.densenet121.export

Profiling Results
------------------------------------------------------------
DenseNet-121
Device                          : Samsung Galaxy S23 (13)
Runtime                         : TFLITE                 
Estimated inference time (ms)   : 1.9                    
Estimated peak memory usage (MB): [0, 2]                 
Total # Ops                     : 312                    
Compute Unit(s)                 : NPU (312 ops)

How does this work?

This export script leverages Qualcomm® AI Hub 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.

import torch

import qai_hub as hub
from qai_hub_models.models.densenet121 import 

# Load the model

# Device
device = hub.Device("Samsung Galaxy S23")

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.

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.

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.

Run demo on a cloud-hosted device

You can also run the demo on-device.

python -m qai_hub_models.models.densenet121.demo --on-device

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.densenet121.demo -- --on-device

Deploying compiled model to Android

The models can be deployed using multiple runtimes:

TensorFlow Lite (.tflite export): This tutorial provides a guide to deploy the .tflite model in an Android application.
QNN (.so export ): This sample app provides instructions on how to use the .so shared library in an Android application.

View on Qualcomm® AI Hub

Get more details on DenseNet-121's performance across various devices here. Explore all available models on Qualcomm® AI Hub

License

The license for the original implementation of DenseNet-121 can be found here.
The license for the compiled assets for on-device deployment can be found here

References

Community

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For questions or feedback please reach out to us.