Teach you how to realize pynq-z2 bar code recognition

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1. Preface

It took nearly a week to realize a two-dimensional code recognition , In this article, I will introduce in detail the pit I have walked through during this period , The code is attached at the end of the text , If you are in urgent need, just turn to the end

2. linux To configure

To achieve this project , First solve the following problems Three main points , It really wastes a lot of time

2.1 solve pynq Connected to the Internet

pynq There are many online tutorials , But I did it for a long time . First, at home , I use

The method shown , And then success ping Internet access In school, this method could not solve , I've tried many methods on the Internet that can't be solved （ Maybe I'm too good ）, Finally, after re burning the image for several times, I found ： Connect the network cable directly to the router in the dormitory Connect to the Internet ...

For details on how to change the download source into an image source, please refer to other blogs

2.2 solve pyzbar Library Download

This library is recommended for download

pip3 install pyzbar

The installation path of this library should also be noted , Type... On the command line

pip3 show pyzbar

Mine is here :

<center> chart 2.2.1. pyzbar The location of </center>

Many say , Below zbar Let me use it

sudo apt-get install python-zbar

obtain , Why not pip3, because pip3 Downloading this always reports an error , Even if it's

pip3 upgrade

Not good either. , No pip3 Version problem . my linux The mirror is v2.3 Version of , I don't know that we all adopt v2.5 Or is it better to be higher

<center> chart 2.2.2. zbar The location of </center>

2.3 solve jupyter Import library

2.3.1 First, explain the origin of the problem

I found the use of

pip3 install pillow

PIL stay jupyter You can import , But it cannot be imported pyzbar Again, I found that on the command line, I entered python3 after , You can import pyzbar, But cannot import zbar

<center> chart 2.3.1. python3 Import pyzbar success , Import zbar You don't succeed </center>

I type... On the command line pyhton Unable to import... Found under the interpreter pyzbar, But you can import zbar And that got my attention , Finally I found out that pip3 To the pyzbar There is a separate storage path ,apt-get Empathy As for why python and python3 Cannot import the same package Then we have to

import syssys.path

Use sentences to observe , Found inconsistent reference paths . I think I know the crux ：

<center> chart 2.3.2. A less smooth explanation </center>

$\color{#FF3030}{ The scarlet letter }$ Not very smooth , Translate into People words Namely ： jupyter To set up for Support quoting Storage pyzbar The path of the package

2.3.2 Method 1 ：

<center> Modify environment variables </center>

explain , Here's a quote ：

Article source address : https://blog.csdn.net/c20081052/article/details/79715132

Linux There are three ways to set environment variables under , One for the current terminal , One for the current user , One for all users ： One ： For the current terminal ： Enter... In the current terminal ：export PATH=$PATH:< Your path to join > However, the above method is only applicable to the current terminal , Once the current terminal is closed or in another terminal , It doesn't work .

  export NDK_ROOT=/home/jiang/soft/Android-ndk-r8e 

It can only be used at the current terminal . Two ： For the current user ： In the user's home directory, there is a .bashrc Hidden files , You can add... To this file PATH The settings are as follows ：

$ gedit ~/.bashrc

Join in ：

export PATH=< Your path to join >:$PATH

If you want to join multiple paths , as long as ：

export PATH=< The path you want to join 1>:< The path you want to join 2>: ...... :$PATH

Each path should be separated by a colon .

This will take effect every time you log in

add to PYTHONPATH The same is true of , stay .bashrc Add

export PYTHONPATH=/home/zhao/setup/caffemaster/python:/home/zhao/setup/mypy:$PYTHONPATH 

After saving, input... At the terminal $ source ~/.bashrc Make environment variables effective immediately

3、 ... and ： For all users ：

$ sudo gedit /etc/profile 

Join in ：

export PATH=< The path you want to join >:$PATH

That's all right. . The input terminal ：echo $PATH You can view the environment variables

Be careful , After modifying the environment variables , Except that the first method takes effect immediately , The second and third method should take effect immediately , Sure source ~/.bashrc Or log out and log in again ！

End of reference

2.3.3 Method 2 ：

<center> Add statements to your code </center>

import syssys.pathsys.path.append('/home/xilinx/.local/lib/python3.6/site-packages')

sys.path Yes view jupyter Library lookup path for , Can view your jupyter Whether the path of your package is included Generally speaking, library import fails for this reason ——jupyter The library path This is the way to set the extra reference path ：

sys.path.append('')

Please refer to this article ： https://www.cnblogs.com/mandy-study/p/7735801.html

3. Provide code

#  Key identification code barcodes = decode(image)def decode (image,barcodes):        # loop over the detected barcodes        for barcode in barcodes:                # extract the bounding box location of the barcode and draw the        # bounding boxr surrounding the barcode on the image        (x, y, w, h) = barcode.rect        cv2.rectangle(image, (x, y),(x + w,y + h), (255, 0, 0), 5)        # the barcode data is a bytes object so if we want to draw it on        # our output image wre need to convert it to a string first        barcodeData = barcode.data.decode("utf-8")        barcodeType = barcode.type        # draw the barcode data and barcode type on the image        text ="{} ({})". format(barcodeData,barcodeType)        cv2.putText(image,text,(x, y - 10), cv2.FONT_HERSHEY_SIMPLEX,.8, (255, 0, 0), 2)         # print the barcode type and data to the terminal        print("[INFO] Found {} barcode: {}".format(barcodeType,barcodeData))            plt.figure(figsize=(10,10))        plt.imshow(image)        plt.show()    # Decoding barcodesdecode(image,barcodes)

final result , I found that the frame didn't fit very well , It may be the problem of taking photos . But the result of identification is completely correct

For the complete code, please refer to the connection ： https://download.csdn.net/download/weixin_44360347/15816188

Open is .ipynb Format .

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