A fast C++ implementation of TensorFlow Lite classification  on a bare Raspberry Pi 4.
Once overclocked to 1950 MHz, your app runs an amazing 33 FPS without any hardware accelerator.
Special made for a bare Raspberry Pi 4 see Q-engineering deep learning examples 
Papers: https://arxiv.org/pdf/1712.05877.pdf 
Training set: COCO with 1000 objects
Size: 224x224 
Frame rate Mobile_V1 Lite : 33 FPS (RPi 4 @ 1950 MHz - 32 bits OS) 
Frame rate Mobile_V2 Lite : 36.2 FPS (RPi 4 @ 1950 MHz - 32 bits OS) 
Frame rate Inception_V2 Lite : 8.9 FPS (RPi 4 @ 1950 MHz - 32 bits OS) 
Frame rate Inception_V4Lite : 1.6 FPS (RPi 4 @ 1950 MHz - 32 bits OS) 
With a 64 bits OS you get higher frame rates see: https://github.com/Qengineering/TensorFlow_Lite_Classification_RPi_64-bits 
To run the application, you have to:
- TensorFlow Lite framework installed. Install TensorFlow Lite 
- OpenCV installed. Install OpenCV 4.5 
- Code::Blocks installed. ($ sudo apt-get install codeblocks)
To extract and run the network in Code::Blocks 
$ mkdir MyDir 
$ cd MyDir 
$ wget https://github.com/Qengineering/TensorFlow_Lite_Classification_RPi_32-bits/archive/refs/heads/master.zip 
$ unzip -j master.zip 
Remove master.zip and README.md as they are no longer needed. 
$ rm master.zip 
$ rm README.md 
 
Your MyDir folder must now look like this: 
tabby.jpeg 
schoolbus.jpg 
grace_hopper.bmp 
Labels.txt 
TensorFlow_Lite_Mobile.cpb 
TensorFlow_Lite_Class.cpp
Next, choose your model from TensorFlow: https://www.tensorflow.org/lite/guide/hosted_models 
Download a quantized model, extract the .tflite from the tarball and place it in your MyDir. 
 
Now your MyDir folder may contain: mobilenet_v1_1.0_224_quant.tflite. 
Or: inception_v4_299_quant.tflite. Or both of course. 
 
Enter the .tflite file of your choice on line 54 in TensorFlow_Lite_Class.cpp 
The image to be tested is given a line 84, also in TensorFlow_Lite_Class.cpp 
 
Run TestTensorFlow_Lite.cpb with Code::Blocks. More info or
if you want to connect a camera to the app, follow the instructions at Hands-On.

