How to know the frequency components of an image

hi all,

I am learning matlab newly. Can anybody help me in knowing the following may a few lines of code..

1. read an image. 2. convert to grayscale 3. See the frequency components of that image. In pictorial view and in numbers. 4. Choosing a linear or non-linear filter to remove specific frequency components.

I have another question like how to know which pixels falls under which frequency or I can ask like how to know which areas in the image are high frequency and which are low frequency...

Answer 1

[Walter Roberson]

Please read the documentation for abs axes fft2 imag imagesc imread imshow real rgb2gray uitable

All pixels in an image partake of every frequency. There are no portions of the image which are more high frequency or low frequency than any other. Frequency analysis of an image involves removing the spacial information.

You could, though, subdivide an image into pieces, and look at the frequency properties of the subsections, thus keeping some spacial information.