Person Detection Model

chipmc · April 7, 2023, 8:32pm

So, I got my hands on an OpenMV Cam H7 Plus. I have updated the latest OpenMV IDE and my firmware is at 4.4.1 (latest). I have been looking at the examples and I watched this video with interest:

I saw in a different post that the person_detection model is not included in the examples. So, I tried building a sketch which would load the person_detection model with this line:

# Load built-in FOMO face detection model
labels, net = tf.load_builtin_model("person_detection")

Unfortunately I am getting an error that the file is not found. I believe this is a built in model as indicated here:

github.com

openmv/openmv/blob/master/src/lib/libtf/README.md#embedding-tensorflow-models-in-the-firmware

# Tensorflow Support
The OpenMV firmware supports loading quantized Tensorflow Lite models. The firmware supports loading external models that reside on the filesystem to memory (on boards with SDRAM), and internal models (embedded into the firmware) in place. To load an external Tensorflow model from the filesystem from Python use [`tf`](https://docs.openmv.io/library/omv.tf.html) Python module. For information on embedding Tensorflow models into the firmware, and loading them, please see the following sections.
  - [Training Tensorflow models](#training-tensorflow-models)
  - [Embedding Tensorflow models in the firmware](#embedding-tensorflow-models-in-the-firmware)
  - [Loading embedded Tensorflow models](#loading-embedded-tensorflow-models)

## Training Tensorflow models
You can use Tensorflow Lite with any high-level API, such as Keras or pytorch, to train and quantize models (for example, see [Training Mobilenet V2 for OpenMV with Keras](https://github.com/SingTown/openmv_tensorflow_training_scripts/blob/main/openmv_mobilenet_v2.ipynb)). However, the officially supported way to train models for OpenMV cameras is using EdgeImpulse. For more information on using EdgeImpulse with OpenMV cameras, please see the [EdgeImpulse tutorial for OpenMV](https://docs.edgeimpulse.com/docs/openmv-cam-h7-plus).

## Embedding Tensorflow models in the firmware
Tensorflow models can be embedded into the firmware for boards that don't have an SDRAM. The firmware ships with a default embedded model, that can be replaced by any other Tensorflow model. Additionally, more models can be embedded in the firmware, as many as the free flash size allows. Once you have a tflite model to replace the default model, or to add to the firmware, it can be embedded in the firmware by placing the model `.tflite` file and its `.txt` labels file in `src/libtf/models`. The model file and labels file must have the same basename, for example:

```bash
models/mask_detection.txt
models/mask_detection.tflite
```

The labels `.txt` file contains model output labels arranged 1 label per line, for example:
```
>>cat mask_detection.txt

This file has been truncated. show original

So, can you please let me know what I am doing wrong? Do I need to load the model onto the microSD card and include a path? Is this model built in as you state in the YouTube video. I am excited about getting started so please excuse all the questions.

Thanks,

Chip

kwagyeman · April 7, 2023, 9:00pm

Hi, the video is out of date. We were shipping the Google person detector model on the camera back then. We just have the FOMO face model on the camera now. If you want the person detection model you can put that on your camera via a TensorFlow Lite file or you can build it into your firmware. I previously helped another user with this on the forums. You should be able to find my post about that.

chipmc · April 7, 2023, 10:01pm

@kwagyeman ,

Thank you - sorry if I did not make my question clear.

I was trying to follow the thread you had on this topic:

From what I saw, this model simply needed to be loaded using the command I referenced above. I have followed the links you provided and I don’t see why the person detection model is not being found.

I will, of course, keep looking. any clues appreciated.

Thanks,

chip

kwagyeman · April 7, 2023, 11:23pm

Hi, you have to put the actual model file and labels in that folder and re-build the firmware. We don’t ship the person model with the firmware anymore.

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Person Detection Model

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