image.fitprofile - Function

Fit 1-dimensional profile with functional forms

Synopsis
fitprofile(values, resid, region, axis, mask, estimate, ngauss, poly, fit, sigma)

Arguments

values	out	Output fitted or estimated profile
		Allowed:	Numeric Glish array
		Default:	None
resid	out	Output residual profile
		Allowed:	Numeric Glish array
region	in	The region of interest
		Allowed:	Region tool
		Default:	Whole image
axis	in	The profile axis
		Allowed:	Integer or unset
		Default:	Spectral
mask	in	OTF mask
		Allowed:	Boolean LEL expression or mask region
		Default:	None
estimate	in	Initial estimate
		Allowed:	Record
		Default:	Unset
ngauss	in	Number of Gaussian elements
		Allowed:	Int
		Default:	1
poly	in	Order of polynomial element
		Allowed:	Int
		Default:	Unset
fit	in	Do fit or get estimate
		Allowed:	T or F
		Default:	T
sigma	in	Weights image
		Allowed:	String or unset
		Default:	unset

Returns
Record or fail

Description
This function fits 1-dimensional models to profiles. All data in the specified region (except along the fitting axis) are averaged.

The behaviour is primarily controlled by argument fit.

If fit==T then you need an estimate. If estimate is unset, then that estimate is automatically provided by fitting ngauss gaussians. If estimate is set then it is used to provide the initial estimate.

The functional form that is actually fit for will be any polynomial specified by the poly argument, plus the number of gaussians present in the estimate.

If fit==F then an estimate is created and returned. If estimate is empty, than an estimate for ngauss gaussians is made. If estimate is not empty, then it is just evaluated.

After calling this function, argument values holds the fitted or estimated profile values, and argument resid holds the fitted or estimated residual profile values.

The output mask is a copy of the default input pixel mask (if any); the OTF mask does not contribute. Any other input pixel masks will not be copied. Use function maskhandler if you need to copy other masks too. Use function calcmask if you need to apply the OTF mask to the output.

Example

- myim := image('gc.small')
- local values, resid
- fit := myim.fitprofile(values, resid, axis=3, fit=T)     # Auto-est and fit

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	Package	general
	Module	images
	Tool	image