Python OpenCV Transforms Traditional Picture Format to base64

Base64 is one of the most common encoding methods for transmitting 8Bit bytecode on the network, and it is a method to represent binary data based on 64 printable characters. Transmitting pictures through http often converts picture data into base64 before transmission.

Introduction to Base64

Base64 is one of the most common encoding methods for transmitting 8Bit bytecode on the network, and Base64 is a method for representing binary data based on 64 printable characters. See RFC2045 to RFC2049 for detailed specifications for MIME.

Base64 encoding is a binary-to-character process that can be used to convey longer identification information in an HTTP environment. For example, in the Java Persistence system Hibernate, Base64 is used to encode a long 1-only identifier (UUID of 128-bit) into a string, which is used as a parameter in HTTP form and HTTP GET URL. In other applications, it is often necessary to encode binary data in a form suitable for URL (including hidden form fields). At this time, Base64 encoding is unreadable and needs to be decoded before reading.

Transfer the picture to base64 in Python

# -*- coding: utf-8 -*-   
import base64   
with open(" / home/chaowei/1.png","rb") as f: 
# b64encode It's coding, b64decode Is decoding  
base64_data = base64.b64encode(f.read()) 
# base64.b64decode(base64data) 
print(base64_data)

Calling base64 encoding in front-end html

<img src="data:image/jpg;base64, This is base64 Code of "/>

In addition, many websites provide API conversion, online encoding and decoding

base64 Convert to Picture

import os,base64 
 
with open("C:\\Users\\wonai\\Desktop\\1.txt","r") as f:
#str = "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"
    imgdata = base64.b64decode(f.read())
    file = open('1.jpg','wb')
    file.write(imgdata)
    file.close()

Python converts base64 to Mat format of opencv

import cv2
import base64
imgData = base64.b64decode(base64_data)
nparr = np.fromstring(imgData, np.uint8)
img_np = cv2.imdecode(nparr, cv2.IMREAD_COLOR)
#cv2.imshow("test",img_np)
#cv2.waitKey(0)

Python converts Mat format of opencv to base64

import cv2
import base64
imgData = base64.b64decode(base64_data)
nparr = np.fromstring(imgData, np.uint8)
img_np = cv2.imdecode(nparr, cv2.IMREAD_COLOR)
 
image = cv2.imencode('.jpg', img_np)[1]
base64_data = str(base64.b64encode(image))[2:-1])