Image Enhancement

Hello readers... this week we are back with new topic in Image Processing which is: Image Processing in Spatial Domain and Frequency Domain.

Why we need to enhance image???
It is because  it improves the interpret-ability or perception of information in images for human viewers. It is also providing better input for other automated image processing techniques

Now, let's take a look about what it is all about with these two different domains..

Spatial Domain	Frequency Domain
2D function f(x,y) represents pixel values	2D function f(x,y) represents frequency values
Techniques that operate directly on pixels	Techniques are based on modifying the Fourier Transform (FT) of an image.
The computational cost of filtering depends on filter size	Cost-filtering is fixed (not-dependant on size of the equivalent spatial domain convolution filter)
Changes in pixel positions correspond to changes in scene.	Changes in image position correspond to changes into spatial frequency
General model: g(x,y) = h(x,y) * f(x,y) + n(x,y) g(x,y) = Degraded image h(x,y) = Degradation function f(x,y) = Original image n(x,y) = Additive noise function	General model: G(u,v) = H(u,v) *F(u,v) + N(u,v) G(u,v) = FT of degraded image H(u,v) = FT of degradation function F(u,v) = FT of original image N(u,v) = FT of noise function

Do you ever know how to determine the frequency of one particular image???
What do frequencies mean in an image ??