CV2 in Python --- 1 part of 5

🧠 Getting Started with OpenCV in Python

Part 1: Introduction & Essential Functions

📌 Series Overview

• Part 1: Introduction & Essential Functions ✅
• Part 2: Reading, Displaying, and Writing Images
• Part 3: Image Processing Basics – Resizing, Cropping, and Color Spaces
• Part 4: Drawing Shapes and Putting Text on Images
• Part 5: Real-time Video Capture and Simple Filters with Webcam

🔑 Essential OpenCV Functions (with Examples)

Function	Description	Example
cv2.imread(path)	Reads an image from a file	image = cv2.imread("sample.jpg")
cv2.imshow(window, image)	Displays the image	cv2.imshow("Image", image) cv2.waitKey(0) cv2.destroyAllWindows()
cv2.waitKey(0)	Waits for a key press	cv2.waitKey(0)
cv2.destroyAllWindows()	Closes OpenCV windows	cv2.destroyAllWindows()
cv2.imwrite(path, image)	Saves the image	cv2.imwrite("output.jpg", image)
cv2.cvtColor(image, flag)	Converts color spaces	gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
cv2.resize(image, (w, h))	Resizes the image	resized = cv2.resize(image, (300, 200))
cv2.GaussianBlur(image, (k, k), 0)	Applies blur	blurred = cv2.GaussianBlur(image, (7, 7), 0)

🧪 Full Example: Combined Use

import cv2

# Load image
image = cv2.imread("sample.jpg")

# Convert to grayscale
gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)

# Resize
resized = cv2.resize(gray, (300, 200))

# Blur
blurred = cv2.GaussianBlur(resized, (7, 7), 0)

# Show and save
cv2.imshow("Processed", blurred)
cv2.imwrite("processed_output.jpg", blurred)

cv2.waitKey(0)
cv2.destroyAllWindows()

🧠 This example combines all the essential OpenCV functions step-by-step. Try it with your own image named sample.jpg!

⌨️ Made with Python & ❤️ by Champak Roy | Part 1 of 5