[AI tutorials] - create tutorials for YOLOv7

Author: eleapttn

pages/platform/ai/deploy_tuto_13_streamlit_yolov7/guide.en-gb.md

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+---
+title: AI Deploy - Tutorial - Create a web service to recognize sign language with YOLOv7
+slug: deploy/tuto-streamlit-yolov7-sign-language
+excerpt: How to build a sign language recognition app with Streamlit
+section: AI Deploy - Tutorials
+order: 13
+updated: 2023-03-31
+---
+
+**Last updated 31th March, 2023.**
+
+## Objective
+
+The purpose of this tutorial is to show how to deploy a web service to recognize **Amercian Sign Language letters** using YOLOv7 model.
+
+In order to do this, you will use [Streamlit](https://streamlit.io/), a Python framework that turns scripts into a shareable web application. You will also learn how to build and use a custom Docker image for a Streamlit application.
+
+For more information on how to train YOLOv7 on a custom dataset, refer to the following [documentation](https://docs.ovh.com/gb/en/publiccloud/ai/notebooks/yolov7-sign-language/).
+
+Overview of the Sign Language recognition app:
+
+![Overview](images/overview-streamlit-yolov7-asl.png){.thumbnail}
+
+## Requirements
+
+- access to the [OVHcloud Control Panel](https://www.ovh.com/auth/?action=gotomanager&from=https://www.ovh.co.uk/&ovhSubsidiary=GB)
+- an AI Deploy project created inside a Public Cloud project
+- a [user for AI Deploy](https://docs.ovh.com/gb/en/publiccloud/ai/users)
+- [Docker](https://www.docker.com/get-started) installed on your local computer
+- some knowledge about building image and [Dockerfile](https://docs.docker.com/engine/reference/builder/)
+- your weights obtained from training YOLOv7 model on the [ASL letters dataset](https://public.roboflow.com/object-detection/american-sign-language-letters/1) (refer to the *"Export trained weights for future inference"* part of the [notebook for YOLOv7](https://github.com/ovh/ai-training-examples/blob/main/notebooks/computer-vision/object-detection/miniconda/yolov7/notebook_object_detection_yolov7_asl.ipynb)
+
+## Instructions
+
+You are going to follow different steps to build your Streamlit application.
+
+- More information about Streamlit capabilities can be found [here](https://docs.streamlit.io/en/stable/).
+- Direct link to the full Python script can be found [here](https://github.com/ovh/ai-training-examples/blob/main/apps/streamlit/sign-language-recognition-yolov7-app/main.py).
+
+> **Warning**
+> You must have previously created an `asl-volov7-model` Object Storage container when training your model via [AI Notebooks](https://docs.ovh.com/gb/en/publiccloud/ai/notebooks/yolov7-sign-language/).
+>
+> Check that this container contains your **YOLOv7 custom weights**. They will be necessary for the deployment of the app!
+
+Here we will mainly discuss how to write the `main.py` code, the `requirements.txt` file and the `Dockerfile`. If you want to see the whole code, please refer to the [GitHub](https://github.com/ovh/ai-training-examples/tree/main/apps/streamlit/sign-language-recognition-yolov7-app) repository.
+
+### Write the Streamlit application
+
+Create a Python file named `main.py`.
+
+Inside that file, import your required modules:
+
+```python
+import streamlit as st
+from PIL import Image
+import numpy as np
+import torch
+import cv2
+import io
+import os
+```
+
+Load the **YOLOv7** model and your own weights. Put this function it in **cache**:
+
+```python
+@st.cache
+def load_model():
+
+    custom_yolov7_model = torch.hub.load("WongKinYiu/yolov7", 'custom', '/workspace/asl-volov7-model/yolov7.pt')
+
+    return custom_yolov7_model
+```
+
+Create the inference function to get prediction:
+
+```python
+def get_prediction(img_bytes, model):
+
+    img = Image.open(io.BytesIO(img_bytes))
+    results = model(img, size=640)
+
+    return results
+```
+
+Write the image analysis function:
+
+```python
+def analyse_image(image, model):
+
+    if image is not None:
+
+        img = Image.open(image)
+        bytes_data = image.getvalue()
+        img_bytes = np.asarray(bytearray(bytes_data), dtype=np.uint8)
+        result = get_prediction(img_bytes, model)
+        result.render()
+
+        for img in result.imgs:
+            RGB_img = cv2.cvtColor(img, cv2.COLOR_BGR2RGB)
+            im_arr = cv2.imencode('.jpg', RGB_img)[1]
+            st.image(im_arr.tobytes())
+
+        result_list = list((result.pandas().xyxy[0])["name"])
+
+    else:
+        st.write("no asl letters were detected!")
+        result_list = []
+
+    return result_list
+```
+
+Define the Python function that displays the letters and forms a word:
+
+```python
+def display_letters(letters_list):
+
+    word = ''.join(letters_list)
+    path_file = "/workspace/word_file.txt"
+    with open(path_file, "a") as f:
+        f.write(word)
+
+    return path_file
+```
+
+Define the main and start your app:
+
+```python
+if __name__ == '__main__':
+
+    st.image("/workspace/head-asl-yolov7-app.png")
+    st.write("## Welcome on your ASL letters recognition app!")
+
+    model = load_model()
+
+    img_file_buffer = st.camera_input("Take your picture in real time:")
+
+    result_list = analyse_image(img_file_buffer, model)
+    path_file = display_letters(result_list)
+
+    if st.button("Clear result"):
+        if os.path.isfile(path_file):
+            os.remove(path_file)
+            print("File has been deleted")
+        else:
+            print("File does not exist")
+
+    if (os.path.exists(path_file)==True):
+        with open(path_file, "r") as f:
+            content = f.read()
+            st.write(content)
+            f.close()
+    else:
+        pass
+```
+
+### Write the requirements.txt file for the application
+
+The `requirements.txt` file will allow us to write all the modules needed to make our application work. This file will be useful when writing the `Dockerfile`.
+
+```console
+torchvision==0.14.0
+numpy==1.23.4
+pandas==1.5.1
+matplotlib==3.6.2
+pillow==9.3.0
+opencv-python-headless==4.6.0.66
+streamlit==1.14.0
+tqdm==4.64.1
+seaborn==0.12.1
+scipy==1.9.3
+ipython==8.6.0
+psutil==5.9.4
+pyyaml==6.0
+```
+
+### Write the Dockerfile for the application
+
+Your Dockerfile should start with the the `FROM` instruction indicating the parent image to use. In our case we choose to start from a `python:3.8` image:
+
+```console
+FROM python:3.8
+```
+
+Create the home directory and add your files to it:
+
+```console
+WORKDIR /workspace
+ADD . /workspace
+```
+
+Install the `requirements.txt` file which contains your needed Python modules using a `pip install ...` command:
+
+```console
+RUN pip install -r requirements.txt
+```
+
+Define your default launching command to start the application:
+
+```console
+CMD [ "streamlit" , "run" , "/workspace/main.py", "--server.address=0.0.0.0" ]
+```
+
+Give correct access rights to **ovhcloud user** (`42420:42420`):
+
+```console
+RUN chown -R 42420:42420 /workspace
+ENV HOME=/workspace
+```
+
+### Build the Docker image from the Dockerfile
+
+Launch the following command from the **Dockerfile** directory to build your application image:
+
+```console
+docker build . -t yolov7-streamlit-asl-recognition:latest
+```
+
+> **Note**
+> The dot `.` argument indicates that your build context (place of the **Dockerfile** and other needed files) is the current directory.
+
+> **Note**
+> The `-t` argument allows you to choose the identifier to give to your image. Usually image identifiers are composed of a **name** and a **version tag** `<name>:<version>`. For this example we chose **yolov7-streamlit-asl-recognition:latest**.
+
+### Test it locally (optional)
+
+Launch the following **Docker command** to launch your application locally on your computer:
+
+```console
+docker run --rm -it -p 8501:8051 --user=42420:42420 yolov7-streamlit-asl-recognition:latest
+```
+
+> **Note**
+> The `-p 8501:8501` argument indicates that you want to execute a port redirection from the port **8501** of your local machine into the port **8501** of the Docker container. The port **8501** is the default port used by **Streamlit** applications.
+
+> **Note**
+> Don't forget the `--user=42420:42420` argument if you want to simulate the exact same behaviour that will occur on **AI Deploy apps**. It executes the Docker container as the specific OVHcloud user (user **42420:42420**).
+
+Once started, your application should be available on `http://localhost:8501`.
+
+### Push the image into the shared registry
+
+> **Warning**
+> The shared registry of AI Deploy should only be used for testing purpose. Please consider attaching your own Docker registry. More information about this can be found [here](https://docs.ovh.com/gb/en/publiccloud/ai/training/add-private-registry).
+
+Find the adress of your shared registry by launching this command:
+
+```console
+ovhai registry list
+```
+
+Login on the shared registry with your usual openstack credentials:
+
+```console
+docker login -u <user> -p <password> <shared-registry-address>
+```
+
+Push the compiled image into the shared registry:
+
+```console
+docker tag yolov7-streamlit-asl-recognition:latest <shared-registry-address>/yolov7-streamlit-asl-recognition:latest
+docker push <shared-registry-address>/yolov7-streamlit-asl-recognition:latest
+```
+
+### Launch the AI Deploy app
+
+The following command starts a new app running your Streamlit application:
+
+```console
+ovhai app run <shared-registry-address>/yolov7-streamlit-asl-recognition:latest \
+	   --gpu 1 \
+	   --default-http-port 8501 \
+	   --volume asl-volov7-model@GRA/:/workspace/asl-volov7-model:RO
+```
+
+> **Note**
+> `--default-http-port 8501` indicates that the port to reach on the app URL is the `8501`.
+
+> **Note**
+> `--gpu 1` indicates that we request 4 CPUs for that app.
+
+> **Note**
+> Consider adding the `--unsecure-http` attribute if you want your application to be reachable without any authentication.
+
+## Go further
+
+- You can imagine deploying an app using YOLO models with an other Python framework: **Flask**. Refer to this [tutorial](https://docs.ovh.com/gb/en/publiccloud/ai/deploy/web-service-yolov5/).
+- Feel free to use **Streamlit** for other AI tasks! Deploy a Speech-to-Text app [here](https://docs.ovh.com/gb/en/publiccloud/ai/deploy/tuto-streamlit-speech-to-text-app/).