HuygensMTF

R2026b

Huygens modulation transfer function result

Since R2026b

Description

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

A HuygensMTF object stores a wave-optics modulation transfer function (MTF) result for one field point in an optical system. A Huygens MTF is computed from a Huygens point spread function (PSF), including diffraction and phase effects. Use a Huygens MTF when the optical system operates near the diffraction limit or when wave-optics effects are important.

Creation

Create a HuygensMTF object by using the mtf object function of an opticalSystem object. To return a HuygensMTF object, specify the Method name-value argument as "Huygens".

Properties

Tangential — Tangential MTF data

Read-only: structure

This property is read-only.

Tangential MTF data, represented as a structure with spatial frequency and MTF values for the tangential direction. The spatial frequency values are in cycles per millimeter, and the MTF values are stored for each wavelength specified when computing the MTF.

Sagittal — Sagittal MTF data

Read-only: structure

This property is read-only.

Sagittal MTF data, represented as a structure with spatial frequency and MTF values for the sagittal direction. The spatial frequency values are in cycles per millimeter, and the MTF values are stored for each wavelength specified when computing the MTF.

FieldPoint — Field point for MTF computation

Read-only: FieldAngle object | FieldPosition object

This property is read-only.

Field point for which the MTF is computed, represented as a FieldAngle object or a FieldPosition object.

Wavelengths — Wavelengths for MTF computation

Read-only: M-element numeric vector

This property is read-only.

Wavelengths used to compute the MTF, represented as an M-element numeric vector. Each element is a wavelength in nanometers.

Data Types: double

FFTLength — FFT size for MTF computation

Read-only: 1-by-2 vector of positive integers

This property is read-only.

FFT size used to compute the optical transfer function from the internal Huygens PSF, represented as a 1-by-2 vector of positive integers. The first element is the number of rows and the second element is the number of columns.

Data Types: double

Object Functions

contrastAtFrequency	Compute MTF contrast at spatial frequencies
frequencyAtContrast	Compute spatial frequency at MTF contrast level
show	Plot analysis result

Examples

Create Huygens MTF Object

Load the sample Double Gauss lens system using zmximport.

opsys = zmximport("DoubleGaussLens.zmx");

Compute the Huygens MTF across all default system field points and wavelengths. Set the Method name-value argument to "Huygens" to enable wave-optics propagation modeling.

mtfr = mtf(opsys, Method="Huygens")

mtfr = 1×3 HuygensMTF array with properties:
    Tangential
    Sagittal
    FieldPoint
    Wavelengths
    FFTLength

Because mtfr is an array of objects, access a single field point by its index before querying nested structural data. Extract the tangential spatial frequency and its corresponding multi-wavelength contrast matrix for the first field point.

% Isolate the MTF result object for the first field point (e.g., on-axis field)
targetFieldMTF = mtfr(1);

% Access the nested properties of the single result object
spatialFreqTan = targetFieldMTF.Tangential.SpatialFrequency;
tangentialMTF  = targetFieldMTF.Tangential.MTF;

Plot Huygens MTF Curves

Load the sample Double Gauss lens system using zmximport. Compute the Huygens MTF across all preconfigured field points in the system. Set MaximumFrequency to 150 cycles/mm to restrict the evaluation domain, and specify an FFTLength of 512 to achieve denser, high-resolution frequency sampling for smoother curve rendering.

opsys = zmximport("DoubleGaussLens.zmx");
mtfr = mtf(opsys, Method="Huygens", MaximumFrequency=150, FFTLength=512);

Visualize the complete spatial frequency performance using the show method. Because mtfr contains data for multiple field points, the function automatically generates a tiled layout with linked axes, displaying one subplot per field point.

hMTF = show(mtfr);
hMTF.Title = "Double Gauss System: Huygens MTF Performance";
hMTF.Grid = "major";

More About

Huygens MTF

A Huygens MTF is a wave-optics modulation transfer function computed from a Huygens PSF. Compared to a Geometric MTF, a Huygens MTF includes diffraction and phase effects.

The mtf object function computes a Huygens PSF, transforms the normalized PSF to an optical transfer function, and returns the magnitude as the MTF. Use this result type for diffraction-aware image quality analysis.

Version History

Introduced in R2026b