Live From Mars was active July 1996-December 1997.
Remember the old Chinese proverb...something about hearing and forgetting,
seeing and learning, doing and remembering. Well, Imaging in Education
covers two of the three sayings...the sayings that count
the most.
But before you jump into the "Readers Digest"-type condensed version of an
Introduction
to the Concept of Imaging in Education, first, go get the
free software, pick
up the lesson images, lesson plans,
Primer for the Teacher and student handouts.
Well OK, to heck with the lessons go get the software and an image or two.
Grab
the small images of the Great Red Spot on Jupiter (60kb) if you're really
short of
time. And I will see you when you get back. But in any case, please do
play with the stuff.
Who of us involved in teaching has not struggled to make difficult
concepts
simple and easy to understand. And who,
involved in this struggle has not turned time and again to visualizing
information as an obvious solution: a solution that offers a way to see
the
unseen. And this seeing the unseen is a fundamental tenet of Imaging in
education.
The comical retort... "Do I need to draw you a picture?" is an appropriate
example
of a natural tendency of our species to be primarily visual. We start in
Kindergarten with the daily calendar. Day, date and brown leaves for
October.
Hey, it works, so we do it.
The Primary grades are full of visual information conveyances. Big books,
flash
cards, the multiplication tables and clocks; singing, dancing, tying your
shoe
blocks and throw the ball junior. In the middle school years, the skeleton
in
the lab closet, the Mercator effect, atoms (when will it be Gluons?),
stars,
planets, cell models and Newton's law. It is no secret to great teaching
that to see an object does wonders for the transfer of ideas.
At this point I have established that the concept of visualizing
information is
not new to you. This is the point I want to hammer home: visualizing
information is a normal way for the species to go about the business of
discovery. Imaging in Education, the subject I am introducing, simply
adds to
the mix, the capabilities of the computer to manipulate images in the
service of
understanding.
As fascinated as I am with how things work, I am going to give you the
condensed version of the fundamentals of Image Processing
in Education.
If you are inclined to this same fascination, check out the following
book list .
Computers only see what they see digitally. And images,
digital images are no more then a string of numbers. Those numbers
control what the computer displays on your screen. The computer shoots
electrons at the back of the screen. Painted on the back of the screen
is several "colors" of phosphor.
The phosphor gets excited by the electrons and in the excitement becomes
luminous. If it is a red phosphor it glows red, green glows green and I
will
let you guess what blue phosphor glows! Through various ways these three
dots
of color together can be seen as any one of 256 colors. Each dot has a
fancy computer name. These dots are forever more (at least in this
document)
called Pixels. Stands for Picture Element if you have to ask. Enough
with the
techie information, on with the show.
Let me introduce you to a piece of free software (freeware) that works on
the
Apple Macintosh computer. This free program is called NIH Image. And it
does
one job brilliantly. Its mission in life is to help humans analyze
pixels. One
pixel at a time, a group of 9 or an array of 300,000 thousand. It
slices, it
dices, it can graph, plot, measure, create data sets (which you can export
to
your favorite spreadsheet for graphing, by the way). NIH Image can
magnify the image, edit, enhance, apply a new coat of colors and teach an
old dog new tricks.
In fact the guys and gals who invented and maintain the software at the
National
Institute of Health (NIH) (now you know...some...of the rest of the story)
take
no less then 3 pages describing the glorious capabilities of NIH Image.
In this venue I will introduce you to about 9 of these tools for image
analysis.
They are:
And for advanced users there is the opportunity to work with density
profiles
and surface plots, both tools that are "too cool for school" according to
my
students.
Beautiful pictures (eg,GIF,JPEG, PICT) versus
images with Scientific merit for study and analysis (eg, TIFF, PDS,
FITS):
To corrupt an image is to change the original image pixel. This change
is actually seen in mini lesson 1c.
Corrupting the pixel value might happen because a photographer wants to
make the image size smaller. This is done because a smaller image file is
easier to use and can be sent quickly to friends and associates. And it
looks
just as good to the human eye as the original bigger file. Maybe better?
So
no harm is done if the photographer is interested in sharing the pictures
beauty. It is still beautiful. But it no longer can be analyzed for
pixel values that have scientific meaning.
One of the first techniques that was used to move images around the
Internet was designed to make the picture as small as possible. That
technique added three letters to each image file so people would
recognize a picture file from a text file. Those three letters are
"GIF" which means Graphical Information Format (I think). This file
shrinking technique works great for maintaining the beauty of a picture
while making the file as small as possible. But all gif files have
corrupted/changed pixel values. Can you guess what the standard file
formats for images on the world wide web is? Yes, GIFs, and
another great file shrinker called JPEG, are the image files of choice.
Smaller files transfer from one computer to another more quickly. And
this is preferred on the net. If you doubt this go get the 1.8 meg
(1,800Kb) 24 bit TIFF image of Jupiter. It is called jupiterWS.tif
I'll bet you dimes to dollars the time it takes to download the image
will try your patience (unless your name is Job).
OK, OK! For all the tech heads, if a technique to shrink and un-shrink
images corrupts the image, it is known as "LOSSY" ( information is lost).
If it does not corrupt the image when it shrinks it is "LOSSLESS" (no
information is lost).
The Image Processing for Teachers project has some great free sample
lessons.
The one most germane to Live From Hubble Space Telescope is a lesson you
can get that lets the kids image process the Moon IO and its spectacular
Volcanoes.
Bringing Image analysis, digital video and the net to the class.
Introduction to the Concept of Imaging in Education
Written by Scott Coletti, Middle School teacher
Crittenden Middle School, Mtn.View, CA.
Please send suggestions or comments to scolett@quest.arc.nasa.gov
Keep in mind that not all images are created (or modified) equally. The
images I have used in the four mini lessons (1a,1b,1c,1d) have scientific
merit for study. That is, the pixel values represent the brightness of
what the Hubble Space Telescope imaged, dot for dot, in Oct of 1995.
Jupiter's brightness or luminosity values (dot for dot)have scientific
merit because the pixel values have not been corrupted. Because they
are not corrupted what you see when you open the Jupiter images is what
the HST "saw".
(Teachers note- To learn what the HST sees and how it sees, I
recommend the activities for program two pages 18 to 26.)
In lesson 1c you change the pixel values of Jupiter by applying filters
from
the process menu inside the program NIH Image. This corruption or change
in pixel value (remember pixel value is nothing more then the brightness
of
the dot, or luminosity of the pixel) occurs when the filter executes a
mathematical formula on groups of pixels (known as arrays). The end
result
is that individual dots are assigned new brightness values based on values
of
surrounding dots.
(Teachers Note- The standard file format for the Mac is called a PICT
file. Guess what...it is corrupted.
Scott L.
Coletti
415-903-6945x237
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