From this Wikipedia link, the fastest fequency for digital frequency is 0.5cycle/sample. It can be rewritten as 1cycle/2sample.
- What does it mean?
- Does it mean that at least two pixles are required to form one cycle?
- Is there any requirement on the values of two samples?
- One must be 0 and the other must be 255? If so, why?
Edit: The reason I have such question is that different cutoff frequencies result in different blurring degree for filtering in frequency domain.
From the link:http://www.imagemagick.org/Usage/fourier/#fft_partial The figure shows the comparison. I hope to estimate blurring degree from cutoff frequency in digital frequency. Maybe I can estimate corresponding standard deviation of Gaussian filter from cutoff frequency.