# Spatial wavelength

I was reading a paper on motion magnification, Eulerian Video Magnification for Revealing Subtle Changes in the World by MIT CSAIL researchers,

where the equation (14) of the paper uses spatial wavelength. I was going through the source code and the wavelength is calculated by:

$$\lambda = \frac{\sqrt{\text{vidHeight}^2+\text{vidWidth}^2}}{N}$$ where $$N$$ is an experimental constant.

Can anyone explain where the formula for spatial wavelength came from?

• I can't tell you, but you do realize that the $\sqrt{\cdots}$ term is the length of the diagonal of a square of dimension $\text{vidHeight}\times\text{vidWidth}$, and that this is probably just the length of something whose width and height can be measured? – Marcus Müller Mar 27 at 11:51
• @MarcusMüller Yes I realize that... I just want to know why it's called the spatial wavelength – DSP Novice Mar 27 at 12:00
• because it's the inverse of a spatial frequency. – Marcus Müller Mar 27 at 12:02
• @MarcusMüller Doesnt Fourier analysis give spatial frequency? Is it just the inverse of the above equation? Sorry, I am new to image processing – DSP Novice Mar 27 at 12:17