1. The problem statement, all variables and given/known data I am given 4 files containing the intensities of a fringe pattern with phase-steps of [tex] \pi/2 [/tex]. I need to do a mesh plot (on MATLAB) of the intensities and phase. 2. Relevant equations [tex] I=A+Bcos(\phi) [/tex] 3. The attempt at a solution I came up with the following equations: [tex] I_1=A+Bcos(\phi) [/tex] [tex] I_2=A+Bcos(\phi+\pi/2) [/tex] [tex] I_3=A+Bcos(\phi+\pi) [/tex] [tex] I_4=A+Bcos(\phi+3\pi/2) [/tex] After the math I get either: [tex] I_4-I_3+I_2-I_1 = 0 [/tex] or [tex] 0.5(I_4-I_3-I_2+I_1) = B(sin\phi + cos\phi) [/tex] Obviously the first is not usable because I can't create a plot and the second contains 'B' in it - which doesn't help since I don't know what B is. Any suggestions at all?