Maixll dock QR code recognition

I don't need to say more about QR code recognition

Salted fish products , Just use it. ~
Choose version ：v831-m2dock-maixpy3-0.5.0-20220601

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Two dimensional bar code / QR code （2-dimensional bar code）
Use a specific geometric figure to move on the plane according to a certain law （ Two dimensional ） Distributed black and white graphics record data symbol information ; A number of geometric shapes corresponding to binary are used to represent literal numerical information , Through image input device or photoelectric scanning device to read automatically to achieve automatic information processing ：
It has some common features of bar code technology ：

• Each code system has its own specific character set ; Each character has a certain width ; It has certain verification function, etc .
• At the same time, it also has the function of automatic identification of different information 、 And processing the rotation change point of the graph .

image modular ：find_qrcodes

One 、 The import module

from maix import image

Two 、 Basic usage

from maix import image
x=image.find_qrcodes()
print(x)

Get the outline coordinates ： Read find_qrcodes() The key value in the dictionary returned by the function is : x , y , w , h The value of is used as the coordinate information of the outline of the QR code ( Blue box ). > Get the coordinates of the inner frame ： Read find_qrcodes() The key value in the dictionary returned by the function is : corners The values in the list of are used as the coordinates of the inner box of the QR code ( Green box ).
Get QR code information ： Read find_qrcodes() The key value in the dictionary returned by the function is : payload As QR code information .
The key values of the dictionary are as follows ：‘x’ , ‘y’ , ‘w’ , ‘h’ , ‘payload’ , ‘version’ , ‘ecc_level’ , ‘mask’ , ‘data_type’ , ‘eci’ , ‘corners’.

Key value	explain
x	Returns the bounding box of the QR code x coordinate (int).
y	Returns the bounding box of the QR code y coordinate (int).
w	Returns the bounding box of the QR code w coordinate (int).
h	Returns the bounding box of the QR code h coordinate (int).
payload	Returns the string of QR code payload , for example URL .
version	Returns the version number of the QR code (int).
ecc_level	Return QR code ECC level (int).
mask	Returns the mask of the QR code (int).
data_type	Return the data type of QR code
eci	Return QR code ECI.ECI Stored QR The code in which data bytes are stored .
qrcode.corners	Returns a four tuple consisting of the four corners of the object (x,y) A list of . The four corners are usually returned clockwise from the upper left corner .

Case study ： Identify QR code

see find_qrcodes() Return information

from maix import display, camera 

while True:
    t = camera.capture()
    mks = t.find_qrcodes()
    print(mks)   #  Output information 
    display.show(t)

The information obtained is as follows ： It's a dictionary

[{‘x’: 49, ‘y’: 41, ‘w’: 168, ‘h’: 160, ‘payload’: ‘xianyujun’, ‘version’: 1, ‘ecc_level’: 3, ‘mask’: 1, ‘data_type’: 4, ‘eci’: 0, ‘corners’: [[49, 52], [211, 41], [217, 201], [69, 196]]}]

After getting the dictionary, we will understand the following code .

Identify QR code

from maix import display, camera 

while True:
    t = camera.capture()
    mks = t.find_qrcodes()
    for mk in mks:
      # Outline data 
      X = mk['x']
      Y = mk['y']
      W = mk['w']
      H = mk['h']
      
      # QR code information 
      string = mk['payload']

      # Inner frame data 
      x1,y1 = mk['corners'][0]   # Access the list of dictionaries 
      x2,y2 = mk['corners'][1]
      x3,y3 = mk['corners'][2]
      x4,y4 = mk['corners'][3]
      
      # Draw frame 
      t.draw_rectangle(X, Y, X + W, Y + H, color=(0, 0, 255), thickness = 2) 
      # Print information 
      t.draw_string(int(X) , int(Y - 35) , str(string), scale = 2.0, color = (255, 0, 0), thickness = 2)  # Inner frame ID
      # Draw the inner frame 
      t.draw_line(x1, y1, x2, y2, color = (0, 255, 0), thickness = 3)  
      t.draw_line(x2, y2, x3, y3, color = (0, 255, 0), thickness = 3)  
      t.draw_line(x3, y3, x4, y4, color = (0, 255, 0), thickness = 3)  
      t.draw_line(x4, y4, x1, y1, color = (0, 255, 0), thickness = 3)  

    display.show(t)

design sketch ：（ Can't recognize complex QR code , The gorgeous one doesn't work .）