How to Install TensorFlow Lite on the Raspberry Pi?

TensorFlow Lite is an optimized framework for deploying machine learning models on edge devices like the Raspberry Pi. By installing TensorFlow Lite, you can run trained ML models for image classification, object detection, speech recognition, and more on your Pi.

Benefits of Running TensorFlow Lite on the Pi

There are several benefits to installing TensorFlow Lite on a Raspberry Pi:

• Enables on-device machine learning inferencing – you can run ML models directly on the Pi instead of relying on the cloud. This improves privacy, reduces latency, and works offline.
• Utilizes the Pi’s capabilities – TensorFlow Lite is optimized to run efficiently on ARM-based systems like the Pi. It can take advantage of the Pi’s hardware acceleration options.
• Smaller model size – TensorFlow Lite models are up to 10x smaller which is important given the Pi’s limited storage.
• Lower power consumption – optimized performance means TensorFlow Lite has a lower power draw which is crucial for battery-powered Pi projects.

With TensorFlow Lite handling machine learning workloads, the Pi can focus on fetching sensor data, controlling electronics, interacting with users, and more.

Prerequisites

Before installing TensorFlow Lite, make sure your Raspberry Pi setup meets these requirements:

• Raspberry Pi OS installed. A 64-bit OS is recommended for better performance.
• Active internet connection for installation.
• MicroSD card with at least 8 GB storage is preferable.
• Power supply for the Pi.
• Keyboard, mouse, monitor for initial setup.

While not mandatory, having a fan or heatsink for the Pi will help during processor intensive ML inferencing.

Installation Guide

Follow these steps to get TensorFlow Lite running on your Pi:

Step 1: Update Package List and Install Prerequisites

Log in to your Pi and open the terminal application. Update your package list and install some prerequisites with these commands:

sudo apt update

sudo apt install libatlas-base-dev libjpeg-dev libtiff5-dev libjasper-dev libpng12-dev libavcodec-dev libavformat-dev libswscale-dev libhdf5-dev libhdf5-103

This will install packages like libatlas, libjpeg libpng, etc. which some TensorFlow Lite operations rely on.

Step 2: Activate the Python 3 Virtual Environment

It’s best practice to install Python packages in a virtual environment. Create and activate one with:

python3 -m venv tflite

source tflite/bin/activate

The virtual environment will keep TensorFlow Lite and its dependencies isolated from the system Python.

Step 3: Install TensorFlow Lite

Inside the activated virtual environment, install the tensorflow-lite package:

pip install tensorflow-lite

This will download and install the latest version of TensorFlow Lite and its dependencies like Numpy.

Step 4: Test the Installation

To validate your installation, open the Python interpreter and try importing TensorFlow Lite:

python

import tflite_runtime.interpreter as tflite

If no errors show up, you have successfully installed TensorFlow Lite!

Optimizing Performance

Here are some tips for getting the best performance out of TensorFlow Lite models on your Pi:

• Choose an optimized model – Use TFLite models designed specifically for ARM devices or mobile apps. They’ll include optimizations for faster inference.
• Limit model size – Smaller models process faster. Aim to keep models under 50 MB.
• Use model quantization – Quantized models (UINT8 and INT8) run faster than floating point models, albeit with slightly lower accuracy.
• Enable hardware acceleration – The Pi’s GPU and NEON SIMD can speed up model execution. Set these to be used in TensorFlow Lite.
• Monitor thermals – High processor utilization causes the SoC to throttle. Use heatsinks, fans or lower clock speeds accordingly.
• Avoid bottlenecks – Profile script execution to prevent I/O routines or software delays from bottlenecking ML performance.

Running a TensorFlow Lite Model

To actually use an ML model, follow these steps:

1. Obtain a model – You’ll need to either train or download a TensorFlow Lite model. The model file will have a .tflite extension. Some pre-trained image classification models are available in this repo.
2. Copy model to Pi – Upload the .tflite file onto your Pi. Faster external storage is preferable over SD card.
3. Import TFLite interpreter – The interpreter interface handles loading models and running inference:

python

import tflite_runtime.interpreter as tflite

interpreter = tflite.Interpreter(model_path="modelname.tflite")

Allocate tensors – Invoke the interpreter to allocate memory for model parameters and input/output buffers:

python

interpreter.allocate_tensors()

Get input/output details – Now query the interpreter to get input/output tensor metadata:

python

input_index = interpreter.get_input_details()[0]["index"]

output_index = interpreter.get_output_details()[0]["index"]

Preprocess input data – Reshape and quantize any input image, audio or other data to match what the model expects:

python

test_image = load_image()  

input_data = preprocess(test_image)

Set input tensor – Copy this data into the interpreter’s input tensor buffer:

python

interpreter.set_tensor(input_index, input_data)

Run inference - Invoke execution:

python

interpreter.invoke()

Get predictions – Fetch the predicted probabilities, classes, bounding boxes etc. from model’s output tensor:

python

predictions = interpreter.get_tensor(output_index)

print(predictions)

See TensorFlow Lite’s documentation for advanced techniques like on-device training, metadata usage, and delegates for acceleration.

Key Takeaways

To recap, the key points about installing TensorFlow Lite on a Raspberry Pi are:

• TensorFlow Lite enables on-device ML inferencing on the Raspberry Pi
• It is optimized to leverage the Pi’s ARM SoC and available hardware acceleration
• Quantized, smaller models deliver the best performance
• The tflite_runtime interpreter API handles loading and running TFLite models
• Proper tensor allocation, input processing, and output parsing are needed
• Optimization techniques like using efficient models, monitoring thermals, and removing bottlenecks are important

So with TensorFlow Lite set up, you can deploy high-performance ML models on your Raspberry Pis! The low power requirements combined with ML acceleration using the GPU/NPU make it an ideal platform for edge AI and embedded IoT applications.

Conclusion

Installing TensorFlow Lite breathes new AI capabilities into the Raspberry Pi. It transforms the tiny single-board computer from a basic Linux box into an on-device machine learning platform able to run customized CNNs, speech recognition systems, anomaly detection, and other neural network models requiring fast low-power inferencing. The optimized TFLite framework maximizes what the Pi’s ARM chipset can offer while minimizing resource usage so complex ML tasks can run even on $35 boards. With the developer-friendly Python API for loading and running models, programmers can easily integrate machine learning into their Pi apps and automation systems. So by combining the flexibility of Pi and the power-efficiency of TFLite, innovative IoT, industrial, medical, financial use cases utilizing embedded AI on the edge become a reality.

Frequently Asked Questions

Q: Does TensorFlow Lite work on all versions of the Pi OS?
A: TensorFlow Lite works best on the 64-bit Raspbian OS. It may install on older 32-bit OSes like Raspberry Pi OS Stretch but has sub-optimal performance due to missing optimizations.

Q: Can I run multiple TFLite models in parallel on the Pi?
A: Yes, multiple Interpreter instances can be created to run separate TFLite models concurrently. However, they will be computationally intensive so adequate cooling is required.

Q: I only have Raspberry Pi 4. Can it still run TensorFlow Lite models?
A: Absolutely! In fact, the Raspberry Pi 4 has better thermals, CPU performance and more RAM making it very suitable for ML workloads. Just make sure to install the 64-bit OS.

Q: Can I train TensorFlow Lite models directly on the Raspberry Pi?
A: While technically possible, training complex neural networks requires significant compute and memory which the Raspberry Pi lacks. It’s better to train models on the cloud and convert them to TFLite format for deployment.

Q: How do I optimize latency and throughput for real-time applications?
A: Using TensorFlow Lite’s experimental delegates like the GPU delegate can lower latency. Reducing model size, batch size 1, INT8 quantization all help. Running at higher clock speeds lowers latency but increases power consumption.

Q: Can I still use TensorFlow Lite if I don’t have an active internet connection?
A: Yes, TensorFlow Lite doesn’t require an internet connection to run models after installation. The models and execution code runs fully offline. Only the initial pip install step needs internet access.

Q: Is there an easy way to convert Keras or TensorFlow models to TFLite?
A: Yes, TensorFlow provides APIs and conversion scripts to easily convert TF or Keras models into the TFLite format. You can also optimize and quantize models during this conversion process.

Q: Can I use a Coral TPU or Google Edge TPU with TensorFlow Lite on the Pi?
A: Yes, the Coral Edge TPU is fully compatible with TensorFlow Lite. It provides hardware acceleration that can speed up inference by 10x or more with supported model operations.

Q: How do I profile TensorFlow Lite model performance on the Pi?
A: TensorFlow Lite provides tracing and profiling tools to measure runtime performance. You can analyze total runtimes, operator execution times, input/output shapes and pinpoint bottlenecks.

Q: Is there detailed documentation available for TensorFlow Lite?
A: Yes, the TensorFlow website has extensive guides on installation, conversion, optimization, model deployment, debugging techniques and much more regarding TensorFlow Lite.

Q: Why is TensorFlow Lite better optimized for embedded devices compared to TensorFlow?
A: TensorFlow Lite only implements a subset of useful operators, has model optimization techniques like quantization and pruning built-in, supports FixedPoint math, and has a smaller binary size overall.