Image Enhancement

2. Image Enhancement: Image enhancement, also known as image sharpening, aims to strengthen detail information such as contour edges in images. Similar to image smoothing, image enhancement can be performed in both spatial and frequency domains. For spatial domain sharpening: subtracting the original image from a processed version yields the sharpened image g(i,j), i.e., g(i,j) = f(i,j) - α[f(i+1,j) + f(i-1,j) + f(i,j+1) + f(i,j-1) - 4f(i,j)] = f(i,j) + 4α[f(i,j) - avg]. Here α is an adjustable factor controlling sharpening intensity, where 1/4 represents the average gray value of the 4 neighboring points around the sharpened pixel.