Image Processing Basics in MATLAB

🖼️ Image Processing Basics in MATLAB

Image Processing involves analyzing, enhancing, and manipulating images to extract useful information or improve visual quality.

MATLAB is widely used for image processing because of its Image Processing Toolbox and simple syntax.
MATLAB is developed by MathWorks.

🔹 What Is an Image?

In MATLAB, an image is a matrix:

Grayscale image → 2D matrix
Color image (RGB) → 3D matrix (Red, Green, Blue)

Each element represents a pixel intensity.

🔹 Types of Images

Image Type	Description
Binary	Black & white (0 or 1)
Grayscale	Shades of gray (0–255)
RGB	Color image (Red, Green, Blue)
Indexed	Uses colormap

1️⃣ Reading & Displaying an Image

🔸 Read Image

🔸 Display Image

📌 imread() reads the image into a matrix
📌 imshow() displays it

2️⃣ Image Information

📌 Shows image dimensions and data type.

3️⃣ Convert Color Image to Grayscale

4️⃣ Convert Image to Binary

📌 Useful for object detection & segmentation.

5️⃣ Accessing Pixel Values

📌 Returns RGB values of a pixel.

6️⃣ Image Resizing

7️⃣ Image Cropping

8️⃣ Image Enhancement

🔸 Adjust Brightness & Contrast

🔸 Histogram Equalization

📌 Improves contrast.

9️⃣ Noise Addition & Removal

🔸 Add Noise

🔸 Remove Noise (Median Filter)

🔟 Edge Detection

📌 Used in object detection & vision systems.

1️⃣1️⃣ Image Histogram

📌 Shows pixel intensity distribution.

⚠️ Important Notes

Images are matrices → matrix operations apply
Pixel values depend on image class (uint8, double)
Image Processing Toolbox is required
Always convert RGB → grayscale when needed

🎯 Interview Questions: Image Processing Basics

🔹 Q1. How is an image represented in MATLAB?

Answer:
As a matrix (2D for grayscale, 3D for RGB).

🔹 Q2. Which function reads an image?

Answer:
imread().

🔹 Q3. How do you display an image?

Answer:
Using imshow().

🔹 Q4. Difference between grayscale and binary image?

Answer:
Grayscale has multiple intensity levels; binary has only 0 or 1.

🔹 Q5. What is histogram equalization?

Answer:
A technique to improve image contrast.

🔹 Q6. Which function is used for edge detection?

Answer:
edge().

✅ Summary

Image processing treats images as matrices
MATLAB provides powerful built-in functions
Common tasks: read, display, enhance, filter
Used in medical imaging, AI, surveillance, robotics

Image Processing Basics in MATLAB