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Plot spatial frequency response of edge


plotSFR(sharpnessMeasurements) plots the spatial frequency response (SFR) measurement of slanted edge ROIs.


plotSFR(sharpnessMeasurements,Name=Value) plots the SFR, specifying additional parameters to control aspects of the display.


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This example shows how to display the spatial frequency response (SFR) plot of a specified subset of the 60 slanted edge ROIs on an Imatest® eSFR chart.

Read an image of an eSFR chart into the workspace.

I = imread("eSFRTestImage.jpg");

Create an esfrChart object, then display the chart with ROI annotations. The 60 slanted edge ROIs are labeled with green numbers.

chart = esfrChart(I);

Measure the edge sharpness in all ROIs and return the measurements in sharpnessTable.

sharpnessTable = measureSharpness(chart);

Display the SFR plot of ROIs 26 and 27 only.

plotSFR(sharpnessTable,ROIIndex=[26 27]);

Input Arguments

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SFR measurements of edges, specified as a table. The plotSFR function supports two types of measurements as described in the following table. You can get both types of sharpness measurements by using the measureSharpness function.

Sharpness of individual ROIs

sharpnessMeasurements has one row for each sampled ROI.

Average sharpness over all ROIs with a particular orientation

sharpnessMeasurements has one row for the average sharpness measurement of all horizontally oriented ROIs, and one row for the average sharpness measurements of all vertically oriented ROIs.

When sharpnessMeasurements is an aggregate sharpness table, m is either 1 or 2, corresponding to the number of sampled orientations.

Data Types: table

Name-Value Arguments

Specify optional pairs of arguments as Name1=Value1,...,NameN=ValueN, where Name is the argument name and Value is the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.

Before R2021a, use commas to separate each name and value, and enclose Name in quotes.

Example: plotSFR(myTable,"ROIIndex",2) displays the measured sharpness only of ROI 2.

ROI indices to display, specified as an integer or vector of integers.

  • When sharpnessMeasurements represents the sharpness measurements of individual ROIs, by default plotSFR creates only one figure, showing the SFR plot from the first row of the table.

  • When sharpnessMeasurements is represents the average sharpness of all ROIs with a particular orientation, plotSFR ignores the specified ROIIndex. Instead, plotSFR creates one figure for each orientation.

Example: 29:32

Data Types: single | double | int8 | int16 | int32 | uint8 | uint16 | uint32

Display plot legend, specified as a numeric or logical 1 (true) or 0 (false). When displayLegend is true, the SFR plot shows a legend that identifies the different curves on the plot.

Display plot title, specified as a numeric or logical 1 (true) or 0 (false). When displayTitle is true, the SFR plot shows a title that indicates the individual ROI index or the orientation of the averaged ROIs.

Parent of the displayed image object, specified as an Axes object.

Version History

Introduced in R2017b

See Also