Storing OpenCV Image in SQLite3 with Python - GeeksforGeeks

24 Jun, 2021
OpenCV is a huge open-source library for computer vision, machine learning, and image processing. OpenCV supports a wide variety of programming languages like Python, C++, Java, etc. It can process images and videos to identify objects, faces, or even the handwriting of a human. When it is integrated with various libraries, such as Numpy. Which is a highly optimized library for numerical operations, then the number of weapons increases in your Arsenal i.e whatever operations one can do in Numpy can be combined with OpenCV.
SQLite is a self-contained, high-reliability, embedded, full-featured, public-domain, SQL database engine. It is the most used database engine on the World Wide Web. Python has a library to access SQLite databases, called sqlite3, intended for working with this database which has been included with Python package since version 2.5.
In this article, we will store an OpenCV image in sqlite3 database with Python. Let’s take this image “gfg.png” as an example:
First import the necessary libraries.
Python3
# import necessary librariesimport cv2import sqlite3import pandas as pd
  
Connect to the sqlite3 database.
 
Python3
# connect to databaseconn = sqlite3.connect("gfg.db")
Create a cursor object and get the current cursor location :
Python3
cursorObject = conn.cursor()
  
Create a new table and commit it to the database.
 
Python3
# create a tablecursorObject.execute("CREATE TABLE imgfg(id string, img blob)")conn.commit()
  
Open the image with open() in read mode.
 
Python3
im = open( 'gfg.png', 'rb' ).read()
Insert the image into the table.
Python3
# open the image you want to store in read moreim = open('gfg.png', 'rb').read()conn.execute("INSERT INTO imgfg VALUES(?,?)",             ("pattern", sqlite3.Binary(im)))
The above statement opens the image and then converts it into a pattern by simply interpreting the binary BLOB context. Finally, it stores that pattern into the table.
Commit to the database.
Python3
conn.commit()
Store the sqlite3 table as a CSV file with pandas.
Python3
# Use pandas to create a dataframe from# the table and save it as a csvtable = pd.read_sql_query("SELECT * FROM imgfg", conn)table.to_csv("imgfg" + '.csv', index_label='index')
The content is stored in the table variable and then it is converted to a CSV file and is saved into the system.
Display the content of the table.
Python3
# display tableprint(table)
Below is the complete program:
Python3
# import necessary librariesimport cv2import sqlite3import pandas as pd # connect to databaseconn = sqlite3.connect("gfg.db")cursorObject = conn.cursor() # create a tablecursorObject.execute("CREATE TABLE imgfg(id string, img blob)")conn.commit() # open the image you want to store in read moreim = open('gfg.png', 'rb').read()conn.execute("INSERT INTO imgfg VALUES(?,?)",             ("pattern", sqlite3.Binary(im)))conn.commit() # Use pandas to create a dataframe from# the table and save it as a csvtable = pd.read_sql_query("SELECT * FROM imgfg", conn)table.to_csv("imgfg" + '.csv', index_label='index') # display tableprint(table)
Output:
CSV generated:
arorakashish0911
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Python-OpenCV
Python-SQLite
Python
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