How to Read Image in MATLAB: Syntax and Example

In MATLAB, you can read an image using the imread function by passing the image file name as a string, like img = imread('filename.jpg'). This loads the image into a matrix variable for further processing.

Syntax

The basic syntax to read an image in MATLAB is:

• img = imread(filename): Reads the image file specified by filename and stores it in the variable img.
• filename is a string with the image file name and extension, e.g., 'photo.png'.
• The output img is a matrix representing the image pixels.

matlab

img = imread('example.jpg');

Example

This example reads an image file named peppers.png (a sample image included with MATLAB) and displays it using imshow.

matlab

img = imread('peppers.png');
imshow(img);

Output

A window opens displaying the colorful peppers image.

Common Pitfalls

• Make sure the image file is in the current folder or provide the full path.
• Use correct file extension and spelling in the filename string.
• Trying to read unsupported or corrupted files will cause errors.
• Remember that imread returns different data types depending on the image format.

matlab

 % Wrong: missing quotes around filename
img = imread(peppers.png);

 % Right:
img = imread('peppers.png');

Quick Reference

Summary tips for reading images in MATLAB:

• Use imread('filename.ext') to load images.
• Supported formats include PNG, JPG, BMP, GIF, TIFF.
• Check current folder or specify full path.
• Use imshow(img) to display the image.

Key Takeaways

Use imread('filename') to load an image file into MATLAB as a matrix.

Ensure the image file is accessible in the current folder or provide full path.

Use imshow(imageMatrix) to display the loaded image.

Always include quotes around the filename string in imread.

Supported image formats include PNG, JPG, BMP, GIF, and TIFF.