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[Python] Implementing TCP image socket(Server, Client)
Sun Mar 21 2021
python
OpenCV
image socket
socket
TCP
1. Introdution
I implemented a TCP image socket between Raspberry pi 4 and an artificial intelligence server in an intersection pedestrian safety notification project last year. We implement a socket that sends and receives real-time and video images on a per-frame basis using OpenCV. If you use Raspberry Pi, the OpenCV installation method is a bit complicated, so please refer to here.
2. TCP image socket Server
When sending and receiving images with TCP socket, the most important thing is to send the same size of the image data from the client to the server. Since the size of the data that can be sent at once using TCP socket is limited, it is important to convert the image data to string and send it. Therefore, it is necessary to receive the size of the image first and receive data from the socket only that size and convert it back to the form of image data.
class ServerSocket:
def __init__(self, ip, port):
self.TCP_IP = ip
self.TCP_PORT = port
self.socketOpen()
self.receiveThread = threading.Thread(target=self.receiveImages)
self.receiveThread.start()
def socketClose(self):
self.sock.close()
print(u'Server socket [ TCP_IP: ' + self.TCP_IP + ', TCP_PORT: ' + str(self.TCP_PORT) + ' ] is close')
def socketOpen(self):
self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
self.sock.bind((self.TCP_IP, self.TCP_PORT))
self.sock.listen(1)
print(u'Server socket [ TCP_IP: ' + self.TCP_IP + ', TCP_PORT: ' + str(self.TCP_PORT) + ' ] is open')
self.conn, self.addr = self.sock.accept()
print(u'Server socket [ TCP_IP: ' + self.TCP_IP + ', TCP_PORT: ' + str(self.TCP_PORT) + ' ] is connected with client')
def receiveImages(self):
try:
while True:
length = self.recvall(self.conn, 64)
length1 = length.decode('utf-8')
stringData = self.recvall(self.conn, int(length1))
stime = self.recvall(self.conn, 64)
print('send time: ' + stime.decode('utf-8'))
now = time.localtime()
print('receive time: ' + datetime.utcnow().strftime('%Y-%m-%d %H:%M:%S.%f'))
data = numpy.frombuffer(base64.b64decode(stringData), numpy.uint8)
decimg = cv2.imdecode(data, 1)
cv2.imshow("image", decimg)
cv2.waitKey(1)
except Exception as e:
print(e)
self.socketClose()
cv2.destroyAllWindows()
self.socketOpen()
self.receiveThread = threading.Thread(target=self.receiveImages)
self.receiveThread.start()
def recvall(self, sock, count):
buf = b''
while count:
newbuf = sock.recv(count)
if not newbuf: return None
buf += newbuf
count -= len(newbuf)
return buf
def main():
server = ServerSocket('localhost', 8080)
if __name__ == "__main__":
main()3. TCP image socket Client
3-1. Sending images(Client)
When sending image data to the server, the Client must hand over the size information of the image data together.
class ClientSocket:
def __init__(self, ip, port):
self.TCP_SERVER_IP = ip
self.TCP_SERVER_PORT = port
self.connectCount = 0
self.connectServer()
def connectServer(self):
try:
self.sock = socket.socket()
self.sock.connect((self.TCP_SERVER_IP, self.TCP_SERVER_PORT))
print(u'Client socket is connected with Server socket [ TCP_SERVER_IP: ' + self.TCP_SERVER_IP + ', TCP_SERVER_PORT: ' + str(self.TCP_SERVER_PORT) + ' ]')
self.connectCount = 0
self.sendImages()
except Exception as e:
print(e)
self.connectCount += 1
if self.connectCount == 10:
print(u'Connect fail %d times. exit program'%(self.connectCount))
sys.exit()
print(u'%d times try to connect with server'%(self.connectCount))
self.connectServer()
def sendImages(self):
cnt = 0
capture = cv2.VideoCapture(0)
capture.set(cv2.CAP_PROP_FRAME_WIDTH, 480)
capture.set(cv2.CAP_PROP_FRAME_HEIGHT, 315)
try:
while capture.isOpened():
ret, frame = capture.read()
resize_frame = cv2.resize(frame, dsize=(480, 315), interpolation=cv2.INTER_AREA)
now = time.localtime()
stime = datetime.utcnow().strftime('%Y-%m-%d %H:%M:%S.%f')
encode_param=[int(cv2.IMWRITE_JPEG_QUALITY),90]
result, imgencode = cv2.imencode('.jpg', resize_frame, encode_param)
data = numpy.array(imgencode)
stringData = base64.b64encode(data)
length = str(len(stringData))
self.sock.sendall(length.encode('utf-8').ljust(64))
self.sock.send(stringData)
self.sock.send(stime.encode('utf-8').ljust(64))
print(u'send images %d'%(cnt))
cnt+=1
time.sleep(0.095)
except Exception as e:
print(e)
self.sock.close()
time.sleep(1)
self.connectServer()
self.sendImages()
def main():
TCP_IP = 'localhost'
TCP_PORT = 8080
client = ClientSocket(TCP_IP, TCP_PORT)
if __name__ == "__main__":
main()3-2. Sending local video
When sending image data to the server, the Client must hand over the size information of the image data together.
class ClientVideoSocket:
def __init__(self, ip, port, video_path):
self.TCP_SERVER_IP = ip
self.TCP_SERVER_PORT = port
self.video_path = video_path
self.connectCount = 0
self.connectServer()
def connectServer(self):
try:
self.sock = socket.socket()
self.sock.connect((self.TCP_SERVER_IP, self.TCP_SERVER_PORT))
print(u'Client socket is connected with Server socket [ TCP_SERVER_IP: ' + self.TCP_SERVER_IP + ', TCP_SERVER_PORT: ' + str(self.TCP_SERVER_PORT) + ' ]')
self.connectCount = 0
self.sendImages()
except Exception as e:
print(e)
self.connectCount += 1
if self.connectCount == 10:
print(u'Connect fail %d times. exit program'%(self.connectCount))
sys.exit()
print(u'%d times try to connect with server'%(self.connectCount))
time.sleep(1)
self.connectServer()
def sendImages(self):
cnt = 0
capture = cv2.VideoCapture(self.video_path)
capture.set(cv2.CAP_PROP_FRAME_WIDTH, 480)
capture.set(cv2.CAP_PROP_FRAME_HEIGHT, 315)
try:
while capture.isOpened():
ret, frame = capture.read()
resize_frame = cv2.resize(frame, dsize=(480, 315), interpolation=cv2.INTER_AREA)
now = time.localtime()
stime = datetime.utcnow().strftime('%Y-%m-%d %H:%M:%S.%f')
encode_param=[int(cv2.IMWRITE_JPEG_QUALITY),90]
result, imgencode = cv2.imencode('.jpg', resize_frame, encode_param)
data = numpy.array(imgencode)
stringData = base64.b64encode(data)
length = str(len(stringData))
self.sock.sendall(length.encode('utf-8').ljust(64))
self.sock.send(stringData)
self.sock.send(stime.encode('utf-8').ljust(64))
print(u'send images %d'%(cnt))
cnt+=1
time.sleep(0.02)
except Exception as e:
print(e)
self.sock.close()
time.sleep(1)
self.connectServer()
self.sendImages()
def main():
TCP_IP = 'localhost'
TCP_PORT = 8080
video_path = './big_buck_bunny_720p_10mb.mp4'
client = ClientVideoSocket(TCP_IP, TCP_PORT, video_path)
if __name__ == "__main__":
main()