findings, conclusions, or recommendations expressed in this material are
those of the developer, PASSPORT TO KNOWLEDGE, and do not necessarily
reflect those of the National Science Foundation.
PASSPORT TO THE SOLAR SYSTEM: Educators Imaging Lessons
An Introduction to the Concept of Imaging in Education
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.
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. This revealing
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. These points establish the concept of visualizing information as a common educational technique.
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.
in Education, the subject I am introducing, simply adds to the mix, the
capabilities of the computer to manipulate images in the service of
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 are 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) take no less than three pages describing the
glorious capabilities of NIH Image.
Beautiful pictures (e.g., GIF, JPEG) versus images with scientific
for study and
analysis (e.g., TIFF, FITS):
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 the Viking Orbiter Mars Data.
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 image is
what the Viking "saw."
To corrupt an image is to change the original image pixel values. 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 for many reasons. The end result is that individual dots are assigned new brightness values based on values of surrounding dots.
Corrupting the pixel value might happen because a photographer wants to make the image file 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 picture's 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. All files using this technique adds 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.
OK, OK! For all the tech heads, if a technique to shrink and unshrink
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).
Note for Windows 3.1 and Windows 95 users: Scion Corporation is making NIH
Image work on Wintel Computers. The program is called Image PC. Recently out of
alpha testing, it is available at http://www.scioncorp.com.
PC users be aware of the following three facts:
This lesson was created and tested on Macs.
All new software is buggy and may cause your machine to crash.
Tracking and reporting your crashes to Scion will improve the product.
Let me know if you successfully used this lesson on a Wintel
SETTING UP THE MAC DESKTOP FOR A QUICK START
When I introduce a new lab to my students, I often use the Mac alias capability for ease of use.
To create Aliases of any file, take the following steps:
Click one time on any file to select.
Go to the word File in the Command line.
Go to the menu Item in File called Make Alias, and let go
In this lesson I created an alias of the image. I drag this alias to the
bottom of the desktop. I have kids double click on the alias of the image
for the anticipatory set. The Mac automatically launches
the application and loads the image to the screen.
Scott Coletti (firstname.lastname@example.org)
Creator of this activity
Bringing Image analysis, digital video and the net to the class.
Scott L. Coletti