Recent content by Shaddyab

How can I find the correlation length of an auto-correlation? Is it the distance to the first zero of the auto-correlation? Is it the distance to the first min. of the auto-correlation? Is it the distance to the first max. of the auto-correlation? or should I integrate? Thank you

I think I am more confused right now. I am trying to fit a biquardatic surface to my data and I would like to know what is the definition of such a surface Thanks

What is the definition of 2D biquardatic surface? is it: ax^2 + by^2 +cx^2y + dxy^2 +exy +fx +gy +h + ix^2y^2 or is it simpler than this.

I am running a Matlab code to solve the problem. The rank and Determinant are estimated using Matlab commands 'rank' and 'det' By saying that "the determinant is not zero BUT it is almost -Inf" I mean that the result of det(A) is around -1e24. I am solving the following problem...

the determinant is not zero BUT it is almost -Inf.

Det(A) is NOT equal to zero. I thought that I can solve it using SVD or pseudo-inverse, but I do not know how to implement this solution. I am trying to find the least square phase ( Phi ) fit to a given slopes slopes. Ax, Ay, and Axy are derivative matrix operators. Can I Impose a B.C to...

I have the following problem: A * Phi = Ax' * Sx + Ay' * Sy where, A= Ax' * Ax + Ay' * Ay + Axy' * Axy and I would like to solve for Phi. Matrix A is: 1)symmetric 2) [89x89] 3) Rank(A)=88 ( I guess it means that there is no unique solution ) 4) Det(A)~=0 ( I guess it means...

As I already mentioned, I am trying to run a very simple case of linear line (X= a1*V+a0) because I already know how to find the uncirtinty in a0 and a1 for this case ( based on the three equations that I have in my first post where var X = SSE/(N-2) ) While: Var(A*) = Z' Var(X) Z =...

I am running a test where I start by preforming a calibration to fit the following linear line V= a * X + b where: X is Displacement, and V is Voltage reading. Then, I acquire my data where I measure V and find X based on X = V/a ( the b drops down ), and find an angle Theta = X/f...

Once again I would like to thank you for your valuable help. I am using what you mentioned in your previous posts to solve the following system of equations for a very simple linear case. X= a1*V+a0 where, X = UA U = [V 1] and A = [a1 a0]'. Defining Z = ((U'U)^-1)U'. and solving the...

1) I disagree with that: if I fit a line as V=m1 * X + b1 and X= m2* V + b2; Then m2 IS NOT equal to 1/m1 and b2 is NOT equal to -b1/m2 you can run a simple Matlab code and see this.2) Can you please re-write the equation to find the Var of A ( Var[A] ) I was not able to understand...

1) Linear fit I am running an experiment to find the linear relation between displacement (X) and voltage reading (V) of the measurement, when fitting a linear line to my measured data, such that: V= m*X + b; Based on the following links...

What is the difference between Auto-correlation and auto-variance? The same for cross-correlation and cross-variance?

I do not think it is only a diagram, they are driving an example.

Thank you for your answer. What is confusing me is that according to this document from Melles Griot http://www.mellesgriot.com/pdf/CatalogX/X_01_27-28.pdf" they should be aligned in a different way ( see figure 1.32 ) So what way reduces the spherical aberration better? Thanks