psifit: Phase Shifting Interferometry

In mlpeck/zernike: Zernike Polynomials and Fringe Analysis tools

Phase Shifting Interferometry

Description

High level function for Least squares analysis of phase shifted interferograms.

Usage

psifit(images, phases, cp = NULL, satarget = NULL, psialg = "ls", options = psfit_options())

Arguments

images	An array containing the interferogram images
phases	A vector of phase shifts
cp	A list describing the pupil boundary, as returned by pupil.pars
satarget	Target 4th and 6th order SA coefficients in non-null tests of aspheres
psialg	String identifying the PSI algorithm to use
options	a list of options

Details

images is a 3 dimensional array with dimensions nrow x ncol x length(phases), where nrow and ncol are the number of rows and columns in the individual interferogram images.

The current values recognized for psialg are

ls

least squares with known phase shifts

aia

the “advanced iterative algorithm“ aiapsi

pc1

pca with pcalg="pc1"

pc2

pca with pcalg="pc2"

pc3

pca with pcalg="pc3"

gpc

my generalized PC algorithm in gpcapsi

pc1thenaia

first pcapsi then aiapsi

pc1thentilt

first pcapsi then tiltpsi

gpcthentilt

first gpcapsi then tiltpsi

tilt

tiltpsi

Value

A list with the following components

phi	wrapped phase estimate
mod	modulation estimate
phases	phase shifts
cp	the interferogram boundary
wf.net	net, unfiltered wavefront (see wf_net)
wf.smooth	Zernike fit wavefront
wf.residual	the difference
fit	Coefficients of Zernike fit to wavefront
zcoef.net	Net Zernike coefficients
extras	any extra data returned by low level functions

Author(s)

M.L. Peck [e-mail]

See Also

lspsi, aiapsi, tiltpsi, gpcapsi, pcapsi

Examples

  ## reuse the files from the demo for an example of two stage fitting
  ## using gpca then tiltpsi
require(zernike)
fpath <- file.path(find.package(package="zernike"), "psidata")
files <- scan(file.path(fpath, "files.txt"), what="character")
for (i in 1:length(files)) files[i] <- file.path(fpath, files[i])

# load the images into an array

images <- load.images(files)

# parameters for this run

source(file.path(fpath, "parameters.txt"))

# phase shifts

phases <- wrap((0:(dim(images)[3]-1))/frames.per.cycle*2*pi)
phases <- switch(ps.dir, ccw = -phases, cw = phases, phases)

# target SA coefficients for numerical null.

sa.t <- sconic(diam,roc,lambda=wavelength)
zopt <- psfit_options()
zopt$satarget <- sa.t
zopt$ptol <- 0.01
tfit <- psifit(images, phases, psialg="gpcthentilt", options=zopt)

mlpeck/zernike documentation built on Dec. 29, 2024, 7:41 p.m.