Image Enhancement: Techniques to Improve Picture Quality
The objective of image enhancement is to improve picture quality by increasing contrast, reducing blur and noise, and correcting geometric distortions, while image restoration is a technique that estimates the original image assuming known models of blur or noise. Image enhancement methods are categorized into frequency domain and spatial domain approaches. Frequency domain methods treat images as 2D signals and employ 2D Fourier transform for signal enhancement, with low-pass filtering to remove noise and high-pass filtering to sharpen edges. Spatial domain algorithms include local averaging and median filtering (using the median pixel value in a local neighborhood) for noise reduction.