v1.2.1

Bug fixes and cleanup

Fixes:

• lpgm_circshift() now supports in-place operation
• bit_reverse_copy() now supports in-place operation
• lpgm_zero_padding_signal() now supports in-place operation

Cleanup:

• Removed 38 generated PGM files from repository
• Updated .gitignore to exclude output*.pgm
• Low pass example now shows proper blur effect

v1.1.0

Filters and noise functions

New:

• lpgm_convolve() - NxN kernel convolution
• lpgm_median_filter() - Median filter
• lpgm_add_salt_pepper_noise() - Add noise
• lpgm_gamma() - Gamma correction

Examples:

• examples/filters/ - Gaussian blur
• examples/noise/ - Denoise with median

Each example folder has homework assignments.

Piciem v1.0.0 - First Stable Release

Piciem v1.0.0 - First Stable Release

A lightweight image processing library in C with zero external dependencies.

Features

• Brightness/Contrast adjustment
• Image inversion (negative)
• Binary and Otsu thresholding
• Histogram equalization
• Sobel edge detection
• DFT and FFT (Cooley-Tukey, ~200× faster)
• PGM file I/O (P2 ASCII, P5 binary)

Bug Fixes

• Fixed critical index bug in pgm_io.c
• Added NULL pointer safety checks
• Fixed VLA stack overflow risk

Performance (512×512)

DFT	FFT
4.39 s	0.02 s