strehlRatio

R2026b

Compute Strehl ratio of Huygens PSF

Since R2026b

Syntax

sr = strehlRatio(psfr)

Description

Add-On Required: This feature requires the Optical Design and Simulation Library for Image Processing Toolbox add-on.

sr = strehlRatio(psfr) computes the Strehl ratio of each Huygens point spread function (PSF) intensity distribution in psfr. The function returns a Strehl ratio for each PSF object and wavelength.

Examples

Compute Strehl Ratio of Huygens PSF

Load the sample Double Gauss lens system using zmximport. Define a field point at an angle of 4 degrees along the x-axis, specify a wavelength of 587.56 nm, and compute the Huygens PSF by setting the Method name-value argument to "Huygens".

opsys = zmximport("DoubleGaussLens.zmx");
fp = fieldPoint(Angles=[4 0]);
lambda = 587.56;
psfr = psf(opsys, FieldPoints=fp, Wavelengths=lambda, Method="Huygens");

Calculate the Strehl ratio of the computed Huygens PSF using the strehlRatio function. The resulting value indicates how closely the optical system approaches ideal, diffraction-limited performance.

sr = strehlRatio(psfr)

sr = 
0.0716

Compute Strehl Ratio for Multiple Wavelengths

Load the sample Double Gauss lens system using zmximport. Define a field point at an angle of 4 degrees along the x-axis and specify an array of three wavelengths (486.13 nm, 587.56 nm, and 656.28 nm).

opsys = zmximport("DoubleGaussLens.zmx");
fp = fieldPoint(Angles=[4 0]);
lambdas = [486.13 587.56 656.28];

Compute the Huygens PSF across all specified wavelengths by setting the Method name-value argument to "Huygens". Use the strehlRatio function to return the performance metrics for each wavelength result.

psfr = psf(opsys, FieldPoints=fp, Wavelengths=lambdas, Method="Huygens");
sr = strehlRatio(psfr)

sr = 1×3

    0.0229    0.0716    0.0451

Input Arguments

psfr — Huygens point spread function results

HuygensPSF object | array of HuygensPSF objects

Huygens point spread function results, specified as a HuygensPSF object or an array of HuygensPSF objects. Create these objects by using the psf object function with the Method name-value argument set to "Huygens".

When you specify an array of Huygens PSF result objects, all objects in the array must use the same wavelengths.

Output Arguments

sr — Strehl ratios

N-by-M numeric array

Strehl ratios, returned as an N-by-M numeric array. N is the number of Huygens PSF objects in psfr, and M is the number of wavelengths. Each value is the ratio of the peak Huygens PSF intensity to the ideal diffraction-limited peak intensity for the same wavelength.

Values close to 1 indicate performance close to the ideal diffraction-limited system.

If a Huygens PSF object contains an empty Image value, the corresponding Strehl ratio values are NaN.

Data Types: double

More About

Strehl Ratio

The Strehl ratio compares the peak intensity of an actual PSF to the peak intensity of an ideal diffraction-limited PSF. For HuygensPSF objects, the stored Image values are already normalized to the ideal diffraction-limited peak intensity.

The strehlRatio object function is available for HuygensPSF objects. It is not a method of GeometricPSF objects.

Version History

Introduced in R2026b