dic_postprocess.analysisRun.makeStrainOverlay

Inputs

referenceImage

Numeric grayscale or RGB image used as the background.

strainMap

Two-dimensional numeric strain field on the DIC grid.

mask

Logical display mask. It is resized to referenceImage by nearest neighbor before blending.

roiMask

Optional logical mask on the strain grid. When nonempty, it determines valid strain samples together with finite strainMap values; otherwise a resized form of mask is used.

opts

Scalar overlay option struct described below.

Required Options

alpha

Strain-color blend fraction; 0 shows the reference and 1 shows the color map inside the overlay mask.

colorRange

Two-element [minimum maximum] strain range mapped to the first and last colormap rows. Values outside the range are clipped.

colormap

N-by-3 RGB colormap.

oversample

Positive strain-grid enlargement factor, rounded to an integer before linear resize. Values below 1 use 1.

sigmaSmooth

Gaussian smoothing sigma on the extended strain grid. Values at or below 0 disable smoothing.

brightness

Additive reference-image brightness adjustment.

contrast

Multiplicative contrast around normalized intensity 0.5.

gamma

Exponent applied after brightness and contrast adjustment.

saturation

Multiplier for the HSV saturation channel.

rgbGain

Three-element red, green, and blue gain vector.

Optional Options

edgeTrim

Nonnegative number of valid-mask edge pixels removed before interpolation. Default: 1 when the field is absent.

Outputs

overlay

Double RGB image with the reference height and width. Reference pixels remain unchanged outside the intersection of mask and valid resized strain data.

Description

The reference is normalized and enhanced first. Valid strain values are extended into their ROI, optionally smoothed, linearly resized, clipped to colorRange, and blended only where both masks permit. The function creates image data only and performs no plotting or file output.

Failure Behavior

referenceImage, strainMap, masks, and every required option must have compatible numeric shapes. Missing fields, an invalid color range or colormap, and incompatible mask/image sizes propagate the originating App helper or MATLAB indexing/conversion error.

Typical Call

opts = struct("alpha", 0.55, "colorRange", [-0.02 0.02], ...
"colormap", jet(256), "oversample", 2, "sigmaSmooth", 1, ...
"edgeTrim", 1, "brightness", 0, "contrast", 1, ...
"gamma", 1, "saturation", 1, "rgbGain", [1 1 1]);
overlay = dic_postprocess.analysisRun.makeStrainOverlay( ...
referenceImage, strainMap, displayMask, roiMask, opts);