The first experiment of Flask introduction

Flask is a Web application development framework based on Python. It is very small but has rich functions. Because it is designed as an extensible framework from the beginning of development, it only has a robust core containing basic services, and other functions can be realized through extension.

The two main dependencies of Flask are: routing, debugging and Web server gateway interface provided by Werkzeug; Jinjia2 provides the template system.

I used pycharm in the experiment. Flash can be installed through file - > Settings - > Project: XX - > Python interpreter - > "+"

When using flash, you need to create a program instance to process all requests received from the client.

from flask import Flask

The next step is to define the route, which is used to deal with the relationship between the url and the function. This function is called the view function. It returns the response to the url, which can be a simple HTML string or a form. Because of the requirements of the job, I used it in the view function

Render in flash_ Template(), which renders the HTML file that has been written, and generates HTML efficiently and flexibly.

@app.route("/",methods=['GET', 'POST'])
#View function
def index():
    return render_template("index.html")

There are also requirements for the placement of html and other files. When creating a project, you should create a new static and Templates folder under the project. Static places static files such as pictures and css, and templates places html files.

Finally, you need to start the server

if __name__=='__main__':
    #Start method

Click the running website to see the experimental results.  

The above is my most basic understanding of flash. Next is my experiment:

In this experiment, I linked MySQL database to read CET4 vocabulary and output it in form; And using pytorch for face detection and comparison.

Click the following two links to jump to the corresponding experimental results respectively.



There are too many face feature vectors, so it's a hasty screenshot.

(the specific html will not be put up, which is very simple) the following is the flash program code, including the link use of the database.

from flask import Flask, render_template
from face import  Face
import pymysql
import torch
from facenet_pytorch import MTCNN, InceptionResnetV1
from torch import device

#Create instance

@app.route("/",methods=['GET', 'POST'])
#View function
def index():
    return render_template("index.html")

@app.route('/word',methods=['GET', 'POST'])
def word():
    with db.cursor() as cursor:
        sql = 'select * from map_enword;'
        result = cursor.fetchall()
        result = list(result)
    return render_template("word.html", result=result)

@app.route('/face_recognition',methods=['GET', 'POST'])
def face_recognition():
    import cv2
    import numpy as np
    import torch
    from facenet_pytorch import MTCNN, InceptionResnetV1

    # Get face feature vector
    def load_known_faces(dstImgPath, savePath, mtcnn, resnet):
        aligned = []
        knownImg = cv2.imread(dstImgPath)  # Read picture
        face = mtcnn(knownImg)  # Use mtcnn to detect faces and return [face array]
        # New face detection
        from torchvision.transforms import ToPILImage
        show = ToPILImage()  # Tensor can be converted into Image to facilitate visualization

        if face is not None:
        aligned = torch.stack(aligned).to(device)
        with torch.no_grad():
            known_faces_emb = resnet(aligned).detach().cpu()  # resnet model is used to obtain the feature vector corresponding to the face
        return known_faces_emb, knownImg

    # Calculate the Euclidean distance between face feature vectors, set the threshold, and judge whether it is the same face
    def match_faces(faces_emb, known_faces_emb, threshold):
        isExistDst = False
        distance = (known_faces_emb[0] - faces_emb[0]).norm().item()
        print("Distance:", round(distance, 2))
        print("Face feature vector\n", known_faces_emb[0], faces_emb[0])
        if (distance < threshold):
            isExistDst = True
        return isExistDst, distance

    device = torch.device('cuda:0' if torch.cuda.is_available() else 'cpu')
    # mtcnn model loading [set network parameters for face detection]
    mtcnn = MTCNN(min_face_size=12, thresholds=[0.2, 0.2, 0.3], keep_all=True, device=device)
    # Used to load face feature vector
    resnet = InceptionResnetV1(pretrained='vggface2').eval().to(device)
    MatchThreshold = 0.8  # Face feature vector matching threshold setting

    known_faces_emb, _ = load_known_faces('static/huge1.jpg', 'static/new_huge1.jpg', mtcnn, resnet)  # Known figure
    # bFaceThin.png  lyf2.jpg
    faces_emb, img = load_known_faces('static/huge2.jpg', 'static/new_huge2.jpg', mtcnn, resnet)  # Figure to be tested
    isExistDst ,distance= match_faces(faces_emb, known_faces_emb, MatchThreshold)  # Face matching
    if isExistDst:
        boxes, prob, landmarks = mtcnn.detect(img, landmarks=True)  # Return face box, probability, 5 face key points
        result = 'matching'
        result = 'Mismatch'

    return render_template("face_recognition.html", result=result, known_faces_emb=known_faces_emb, faces_emb=faces_emb, distance=distance)
if __name__=='__main__':
    #Start method

# if __name__ == '__main__':
#     from gevent import pywsgi
#     server = pywsgi.WSGIServer(('', 5000), app)
#     server.serve_forever()

Tags: Python Flask

Posted by mikejohnston on Thu, 19 May 2022 02:40:12 +0300