How Do You Calculate the Contrast of a Sinusoidal Grating?

[isabelle87]

Homework Statement

Sorry if this comes out the wrong way, but I have to translate my problem from norwegian to english... but I'll give it a shot ;)

Task 1a was to find some maximal and minimal amplitudes.
Those I found: max 30 units and min 10s unit.

Task 1b is to use these amplitudes to find the contrast of the sinusoidal grating.
This I have no idea how to do.
Can someone please show me what to do - and also explain what you do and why you do it?

Homework Equations

perhaps: h sin ø = lamda ?
But then again, what has lamda to do with any of this? :S

The Attempt at a Solution

 

[member 553083]

The contrast of a sinusoidal grating can be calculated using the following formula:Contrast = (Max amplitude - Min amplitude) / (Max amplitude + Min amplitude)In this case, the max amplitude is 30 units and the min amplitude is 10 units. Therefore, the contrast is:Contrast = (30 - 10) / (30 + 10) = 20 / 40 = 0.5This means that the contrast of the sinusoidal grating is 0.5.