[python] Hand gesture recognition in Python using OpenCV

https://github.com/ishfulthinking/Python-Hand-Gesture-Recognition

https://docs.python.org/ko/3/library/turtle.html

turtle — 터틀 그래픽¶

소스 코드: Lib/turtle.py

소개

Turtle graphics is an implementation of the popular geometric drawing tools introduced in Logo, developed by Wally Feurzeig, Seymour Papert and Cynthia Solomon in 1967.

Turtle star

turtle은 간단한 움직임을 반복하는 프로그램을 사용하여 복잡한 모양을 그릴 수 있습니다.

In Python, turtle graphics provides a representation of a physical “turtle” (a little robot with a pen) that draws on a sheet of paper on the floor.

It’s an effective and well-proven way for learners to encounter programming concepts and interaction with software, as it provides instant, visible feedback. It also provides convenient access to graphical output in general.

Turtle drawing was originally created as an educational tool, to be used by teachers in the classroom. For the programmer who needs to produce some graphical output it can be a way to do that without the overhead of introducing more complex or external libraries into their work.

Tutorial

New users should start here. In this tutorial we’ll explore some of the basics of turtle drawing.

Starting a turtle environment

In a Python shell, import all the objects of the turtle module:

from turtle import *

If you run into a No module named '_tkinter' error, you’ll have to install the Tk interface package on your system.

Basic drawing

Send the turtle forward 100 steps:

forward(100)

You should see (most likely, in a new window on your display) a line drawn by the turtle, heading East. Change the direction of the turtle, so that it turns 120 degrees left (anti-clockwise):

left(120)

Let’s continue by drawing a triangle:

forward(100)
left(120)
forward(100)

Notice how the turtle, represented by an arrow, points in different directions as you steer it.

Experiment with those commands, and also with backward() and right().

펜 제어

Try changing the color - for example, color('blue') - and width of the line - for example, width(3) - and then drawing again.

You can also move the turtle around without drawing, by lifting up the pen: up() before moving. To start drawing again, use down().

The turtle’s position

Send your turtle back to its starting-point (useful if it has disappeared off-screen):

home()

The home position is at the center of the turtle’s screen. If you ever need to know them, get the turtle’s x-y co-ordinates with:

pos()

Home is at (0, 0).

And after a while, it will probably help to clear the window so we can start anew:

clearscreen()

Making algorithmic patterns

Using loops, it’s possible to build up geometric patterns:

for steps in range(100):
    for c in ('blue', 'red', 'green'):
        color(c)
        forward(steps)
        right(30)

- which of course, are limited only by the imagination!

Let’s draw the star shape at the top of this page. We want red lines, filled in with yellow:

color('red')
fillcolor('yellow')

Just as up() and down() determine whether lines will be drawn, filling can be turned on and off:

begin_fill()

Next we’ll create a loop:

while True:
    forward(200)
    left(170)
    if abs(pos()) < 1:
        break

abs(pos()) < 1 is a good way to know when the turtle is back at its home position.

Finally, complete the filling:

end_fill()

(Note that filling only actually takes place when you give the end_fill() command.)

How to…

This section covers some typical turtle use-cases and approaches.

Get started as quickly as possible

One of the joys of turtle graphics is the immediate, visual feedback that’s available from simple commands - it’s an excellent way to introduce children to programming ideas, with a minimum of overhead (not just children, of course).

The turtle module makes this possible by exposing all its basic functionality as functions, available with from turtle import *. The turtle graphics tutorial covers this approach.

It’s worth noting that many of the turtle commands also have even more terse equivalents, such as fd() for forward(). These are especially useful when working with learners for whom typing is not a skill.

You’ll need to have the Tk interface package installed on your system for turtle graphics to work. Be warned that this is not always straightforward, so check this in advance if you’re planning to use turtle graphics with a learner.

Use the turtle module nam

1. Pandas

Pandas is a software library written for the python programming language for data manipulation and analysis.

Pandas is well suited for many different kinds of data:

• Tabular data with heterogeneously-types columns.
• Ordered and unordered time series data.
• Arbitrary matrix data with row and column labels.
• Any other form of observational / statistical data sets.

 The data actually need not be labeled at all to be placed into a pandas data structure.

2. NumPy

Numpy is the core library for scientific computing in Python. It provides a high-performance multidimensional array object, and tools for working with these arrays.

3. Matplotlib

Matplotlib is a Python package used for 2D graphics.

• Bar graph
• Histograms
• Scatter Plot
• Pie Plot
• Hexagonal Bin Plot
• Area Plot

4. Selenium

The selenium package is used to automate web browser interaction from Python.

5. OpenCV

OpenCV- Python is a library of Python designed to solve computer vision problems.

6. SciPy

Scipy is a free and open-source Python library used for scientific computing and technical computing.

7. Scikit-Learn

Scikit-learn (formerly scikits.learn) is a free software machine learning library for the Python programming language. It features various classification, regression and clustering algorithms.

8.  PySpark

The Spark Python API (PySpark) exposes the Spark programming model to Python.

9. Django

Diango is a Python web framework. A framework provides a structure and common methods to make the life of a web application developer much easier for building flexible, scalable and maintainable web applications

• Django is a high-level and has a MVC-MVT styled architecture.
• Django web framework is written on quick and powerful Python language.
• Django has a open-source collection of libraries for building a fully functioning web application.

10. Tensor Flow

TensorFlow is a Python library used to implement deep networks. In TensorFlow, computation is approached as a dataflow graph.

https://www.geeksforgeeks.org/stack-in-python/

A stack is a linear data structure that stores items in a Last-In/First-Out (LIFO) or First-In/Last-Out (FILO) manner. In stack, a new element is added at one end and an element is removed from that end only. The insert and delete operations are often called push and pop.

The functions associated with stack are:

• empty() – Returns whether the stack is empty – Time Complexity: O(1)
• size() – Returns the size of the stack – Time Complexity: O(1)
• top() / peek() – Returns a reference to the topmost element of the stack – Time Complexity: O(1)
• push(a) – Inserts the element ‘a’ at the top of the stack – Time Complexity: O(1)
• pop() – Deletes the topmost element of the stack – Time Complexity: O(1)

Implementation:

There are various ways from which a stack can be implemented in Python. This article covers the implementation of a stack using data structures and modules from the Python library. 
Stack in Python can be implemented using the following ways: 

• list
• Collections.deque
• queue.LifoQueue

# Python program to
# demonstrate stack implementation
# using list
 
stack = []
 
# append() function to push
# element in the stack
stack.append('a')
stack.append('b')
stack.append('c')
 
print('Initial stack')
print(stack)
 
# pop() function to pop
# element from stack in
# LIFO order
print('\nElements popped from stack:')
print(stack.pop())
print(stack.pop())
print(stack.pop())
 
print('\nStack after elements are popped:')
print(stack)
 
# uncommenting print(stack.pop())
# will cause an IndexError
# as the stack is now empty

Create a Video Chat/Video Steaming App using Python

https://medium.com/geekculture/creating-video-chat-app-using-python-9da0a9c386ba

Server.py

from pyfiglet import Figlet
os.system("clear")
pyf = Figlet(font='puffy')
a = pyf.renderText("Video Chat App without Multi-Threading")
b = pyf.renderText("Server")
os.system("tput setaf 3")
print(a)
import socket, cv2, pickle,struct
# Socket Create
server_socket = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
host_name  = socket.gethostname()
host_ip = socket.gethostbyname(host_name)
print('HOST IP:',host_ip)
port = 9999
socket_address = (host_ip,port)
# Socket Bind
server_socket.bind(socket_address)
# Socket Listen
server_socket.listen(1)
print("Listening at:",socket_address)
# Socket Accept
while True:
 client_socket,addr = server_socket.accept()
 print('Connected to:',addr)
 if client_socket:
  vid = cv2.VideoCapture(0)
  
  while(vid.isOpened()):
   ret,image = vid.read()
   img_serialize = pickle.dumps(image)
   message = struct.pack("Q",len(img_serialize))+img_serialize
   client_socket.sendall(message)
   
   cv2.imshow('Video from Server',image)
   key = cv2.waitKey(10) 
   if key ==13:
    client_socket.close()

Client.py

from pyfiglet import Figlet
os.system("clear")
pyf = Figlet(font='puffy')
a = pyf.renderText("Video Chat App without Multi-Threading")
b = pyf.renderText("Client")
os.system("tput setaf 3")
print(a)
import socket,cv2, pickle,struct
# create socket
client_socket = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
#  server ip address here
host_ip = '<IP>' 
port = 9999
client_socket.connect((host_ip,port)) 
data = b""
metadata_size = struct.calcsize("Q")
while True:
 while len(data) < metadata_size:
  packet = client_socket.recv(4*1024) 
  if not packet: break
  data += packet
 packed_msg_size = data[:metadata_size]
 data = data[metadata_size:]
 msg_size = struct.unpack("Q",packed_msg_size)[0]
 
 while len(data) < msg_size:
  data += client_socket.recv(4*1024)
  frame_data = data[:msg_size]
  data  = data[msg_size:]
  frame = pickle.loads(frame_data)
  cv2.imshow("Receiving Video ",frame)
  key = cv2.waitKey(10) 
  if key  == 13:
   break
client_socket.close()

PyAudio

https://pypi.org/project/PyAudio/

PyAudio는 크로스 플랫폼 오디오 I/O 라이브러리인 PortAudio v19에 대한 Python 바인딩을 제공합니다. PyAudio를 사용하면 Python을 사용하여 GNU/Linux, Microsoft Windows 및 Apple macOS와 같은 다양한 플랫폼에서 오디오를 쉽게 재생하고 녹음할 수 있습니다.

pip install PyAudio