Using SMART - Help

clanmurderUrban and Civil

Nov 15, 2013 (4 years and 8 months ago)



A quick guide to using the SMART (
nalysis and
esting) Macro in
conjunction with SCION Image or NIH Image to
measure SEM resolution, imaging performance and

Problems, questions, suggestions for improvements ?

please let me know ……...

Version 6.0 gamma

What does SMART do?

SMART currently provides three options

(1) Manual and Automatic Fourier analysis
resolution testing

(2) An alternative Autocorrelation mode to
measure image resolution

(3) A superposition diffractogram mode for
precision resolution measurement including time
dependent drift and instabilities

An implementation of the Frank and Al Ali
algorithm to measure signal to noise ratios

and please note...

Although the MACRO language of IMAGE is good
there are some things I could not make it do. If
you can help improve the interface and usability
of SMART please let me know how.

This is a work in progress so check back on our
website for periodic improvements

The code is copyright 2001 to the author. Feel
free to use it and modify it as you wish. If you
use it in a publication a citation or an
acknowledgement would be welcome

Go forth and magnify…….

Setting up SCION or NIH Image

Before using SMART you must
set up SCION or NIH Image

Go to the Options menu and
click on Preferences

Edit the “Undo &Clipboard
Buffer Size” to
at least 2000k
ideally 4000k, then click OK.
Unless this is done
this macro
may not work properly

may even fail completely

Go to File and Exit the Image
program. This saves the
preference setting to disc

Then restart Image

Loading SMART

Go to the Special menu and
click on “Load Macros”

Navigate your way to the
folder where you stored
SMART and click Open in the
dialog box



it is a good idea to
store SMART in the MACRO
folder of Image

all output data
appears in the INFO box. It
is also a good idea to try and
position this box some
where it is always visible.

Ready to go

If you click on the
Special menu item
again then the drop
down menu will now
show the new options
that are offered by the
SMART macro

Clicking on any of
these new entries in
the menu will start
that function

Automeasure resolution



Load the micro
graph you wish to analyze
(using the File menu).
NIH and SCION image can use
almost any standard image
file format. The number of
pixels in the image is not

Go to the SPECIAL menu
and select an ROI (128 up
to 512). Position the ROI
by clicking and dragging.

Automeasure Resolution

Go to SPECIAL menu and
click the first option

AutoMeasure Resolution.

A dialog box appears and
asks for the width of

this is is width of
the field of view of the
entire image in microns.
Calculate or measure this
value from the micron

Enter the data and click OK

Total image width (microns)

Calculate width from the scale marker

The FFT display

After some processing the
screen now shows the FFT



if the dialog box
covers the FFT drag it out
of the way, but don’t click
OK until you are ready

The program has
attempted to separate the
signal from the noise. In
many cases the guess that
is made is good but you
can adjust the result to
your own needs...

The threshold toolbar

Click on the Threshold tool

Then put the cursor in the
LUT window and drag the
cursor up and down to
change the threshold level

Too low a value of the
threshold will reveal the
noise in the background,
too high a value may cut
off some of the signal and
give a pessimistic result

When satisfied click OK

Threshold tool

LUT window

Threshold too low

Resolution result

The info box now shows the
computed resolution (in nm)
determined from the average
of the length of the major
and minor axes of the ellipse
fitted to the FFT.

The eccentricity of the FFT is
a measure of the stigmatic
error in the beam. Ideally the
value should be zero

anything less than about 0.1
is evidence of good

Manual Resolution Mode

A manual mode is also

The initial steps in this are
identical with the automatic

Instead of relying on fitting
an ellipse to the signal region
calibrated rings are
superimposed on the power
transform so the user can
visually determine resolution

In cases where the signal
transform is not circular this
is more accurate

0.35nm resolution

Mode 2


This mode does an auto
correlation of the FFT of
the image to determine the
information cut
off. No
user intervention is needed

Load the image then go to
the Special menu and
select your ROI

When the ROI is set then
go to the Special menu
again and select the
AutoCorrelation mode


step 2

After you answer the
question about the image
width the program will
display the 2
D Auto
Correlation plot as shown

The macro measures the
width of the correlation
peak at 20% of maximum

This width gives the

of the image at
the information cut

Line profile across correlation

Mode 3

Two Image Analysis

This part of SMART uses
two images to give an
accurate measure of
resolution and drift

The two images should be
recorded one directly after
the other. Do not adjust
the stage, focus, gun etc..

Load the two images then
go to the SPECIAL menu
select and position the ROI
on the top image.
must be smaller than the
image size

Image 1

Image 2

Mode 3

step 2

After you calibrate the
image size as usual the
Macro copies the image in
the ROI from image 1,
puts the same ROI on
image 2 but shifted
horizontally by 16 pixels,
copies that image area,
then forms a composite
image from these two
fragments. The 2
D power
spectrum is then
calculated and displayed

D power spectrum from
composite image

Resolution analysis


present on a pixel
by pixel basis in both images
appears modulated by the
fringes in the FFT. Noise is
unmodulated and so is
readily distinguished from
image detail

Calibrated rings are
superimposed over the
fringed FFT so that the
resolution can be visually

Here fringes can be seen
extending to below 2.5 nm

Measuring Drift

The fringes should be
vertical because the
images are offset
horizontally by 16 pixels

If drift or instability
occurs the fringes will
rotate through some angle
. The actual drift direction
is then in the indicated





Note that…….

The resolution result given by this mode averages over the
time interval required to record both images and so is a
good test of real world resolution.

This routine has failed to work on some computers,
apparently because of screen driver problems with the
SWITCH command. If the macro fails to work for you, load
both images as usual, position the ROI on image 1, then
manually put the ROI in position on image 2 as well, then
run the Two Image routine.

On small monitor screens, or when using big images, the
INFO box may sometimes be hidden. Try and move it to a
convenient corner of the screen before starting an analysis.

S/N ratio measurement

To use this mode, load the
image of choice then select
S/N mode. The Frank and Al
Ali algorithm is used on
alternate line pairs of data

The computation takes a few
seconds so please be patient

The result appears in the


This works best when the
detail in an image is large
compared to the pixel size
(i.e. images with empty