Image capture using Python - Flask application programming interface(API) | Python

Image capture using Python - Flask application programming interface(API)

Article Creation Date : 19-Nov-2021 10:53:59 AM
Code to record the screen for a duration of 60 seconds. The recording is saved in the form of frames in .jpg format into the destination file. Flask is used to build web-application in the code.The project requires libraries like Flask, cv2 library from OpenCV used to perform image processing, datetime for creating stamps and storing the .jpg files without replacement for a duration of 60 seconds.

#Sadasivuni Durga
from flask import Flask, render_template, Response, requestimport cv2
import datetime, time
global capture,rec_frame,rec, out 
capture=0
switch=1
rec=0

#instatiate flask app  
global app
app = Flask(__name__, template_folder='./templates')
camera = cv2.VideoCapture(0)

# record with interval of 0.05 seconds
def record(out):
    
    while(rec):
        time.sleep(0.05)
        out.write(rec_frame)

# generate frames 

def gen_frames():
    global out, rec_frame
    # generate frames and read it
    
    while True:
        success, frame = camera.read() 
        if success:
           
            if(rec):
                rec_frame=frame
                frame= cv2.putText(cv2.flip(frame,1),"Shots begin...", (0,25), cv2.FONT_HERSHEY_SIMPLEX, 1, (0,0,255),4)
                frame=cv2.flip(frame,1)
 
            try:
                ret, buffer = cv2.imencode('.jpg', cv2.flip(frame,1))
                frame = buffer.tobytes()
                yield (b'--frame\r\n'
                       b'Content-Type: image/jpeg\r\n\r\n' + frame + b'\r\n')
            except Exception as e:
                pass
                
        else:
            pass

# index.html is required to render template
@app.route('/')
def index():
    return render_template('index.html')


@app.route('/video_feed')
def video_feed():
    return Response(gen_frames(), mimetype='multipart/x-mixed-replace; boundary=frame')

# GET or POST requests made to HTML
@app.route('/requests',methods=['POST','GET'])
def tasks():
    global out
   
    if request.method == 'POST':

        if  request.form.get('rec') == 'Start Recording':
            global rec
            rec= not rec
            capture_duration=1
            cap = cv2.VideoCapture(0)
            rec, frame = cap.read()
            start_time = time.time()
            count=0
            
            if(rec):
                while( int(time.time() - start_time) < capture_duration ):                   
                    rec, frame = cap.read()
                    now=datetime.datetime.now()
                    out = cv2.imwrite('img_{}.jpg'.format(str(now).replace(":",'')),frame)
                    
                    count+=1
        camera.release()
    return 'Task Done!'


# main program                

if __name__ == '__main__':
    app.run()

The "index.html" file plays the front end role part. The visible webpage needs to get data from the camera and save the same to the destination folder. The function of getting data from the camera is done by "POST" method using a submit button named " Start Recording". The entire HTML code is depicted below:

<body>
<div class="container">
    <div class="row">
        <div class="col-lg-8  offset-lg-2">
			<form method="post" action="{{ url_for('tasks') }}">
			<input type="submit" value="Start Recording" name="rec" />
			</form>
            <img src="{{ url_for('video_feed') }}" height="60%">

			<li>Start Recording..</li>	
			
        </div>
    </div>
</div>
</body>

 The output on python IDLE running is shown below

Copy and paste the URL into the web browser. This will redirect to index.html page.

Once you click the start recording  button, the screen will be recorded and output is saved in the form of frames.