Image Processing in MIPS Assembly

Overview

This project demonstrates low-level image processing using MIPS assembly.
It performs thresholding, matrix transformations, and basic cryptographic blurring on grayscale images stored in the .pgm (Portable GrayMap) format.

By working directly with pixel data, it shows how image transformations can be achieved through manual memory management, matrix arithmetic, and file I/O syscalls in MIPS.

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Features

• Thresholding — Converts grayscale images to binary (black and white) using a set intensity threshold.
• Matrix Transformations — Performs scaling, rotation, and shearing via affine transformation matrices.
• Cryptography / Blur Simulation — Manipulates pixel data for encryption-like visual distortion.
• File I/O in MIPS — Reads and writes .pgm image files using syscalls 13–16.
• Automated Testing — Built-in test data for each function (threshold, transform, cryptography).

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Technologies

• Language: MIPS Assembly
• Simulator: MARS MIPS Simulator
• Image Format: PGM (P5, binary)
• Files Used:
  • lenna.pgm — sample input image
  • textfile.pgm — text-based input image for blur/encryption tests

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Project Structure

Image-Processing-MIPS ImageProcessing.s # MIPS assembly source code lenna.pgm # Test input image (512x512 grayscale) textfile.pgm # Text-based PGM file used for blur/encryption tests README.md # Project documentation

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How to Run

1. Open ImageProcessing.s in MARS.
2. Make sure lenna.pgm and textfile.pgm are in the same directory.
3. Assemble (F3) and run (F5).

Output Files Generated

• lenna_thresh.pgm – result of thresholding
• lenna_rotation.pgm – rotated image
• lenna_scale.pgm – scaled image
• lenna_shear.pgm – sheared image
• text_crypt.pgm – blurred or encrypted text file

Viewing Results

Open the output .pgm files in an image viewer such as GIMP, IrfanView, or Visual Studio Code with an image preview extension.

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Concepts Demonstrated

• Image buffer manipulation in memory
• Affine matrix transformations in assembly
• Loop and branch optimization
• File handling syscalls (13–16: open, read, write, close)
• Threshold-based pixel classification

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Example Workflow

1. Input: textfile.pgm (renders readable English text)
2. Operation: Apply cryptography function (custom blur)
3. Output: text_crypt.pgm (blurred or distorted text)

The visual output should show blurred or altered text depending on the implemented algorithm.

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Author

Calvin Poruthur Raju
Email: [calvinpraju@gmail.com]
LinkedIn / GitHub: [https://www.linkedin.com/in/calvin-raju/]

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Keywords

MIPS Assembly, Image Processing, PGM, Affine Transform, Thresholding, Cryptography, Low-Level Programming