Digital images are recorded and transferred as pixels. The more pixels
that are used, the better or more clear the image is (this is often referred
to as RESOLUTION). However, the more pixels that are
used to create an image, the more memory is required. Many images found
on the Internet are 256 pixels long by 256 pixels wide.
|How many pixels in a 256 by 256 image?||256 * 256 = 65,536 pixels|
|Many satellite images are 512 pixels long by 512 pixels wide. How many pixels is that?||512 * 512 = 262,144|
|How long would it take you to read that many data points over the telephone?||262,144 seconds is more than 3 days working 24 hours a day non-stop|
This is one reason that scientists must work in teams - to split up the work so the final product can be finished faster.
NASA scientists are always trying to figure out ways to increase the speed at which digital information can be converted into pictures. Hopefully, your students were able to come up with strategies to increase the speed of the process - have your students share these DATA COMPRESSION ROUTINES. For example, students can say the next 20 pixels are all white instead of saying "white" twenty times. Be creative!
Extensions and Investigations:
Investigate the software program that came with your scanner and/or digital camera. These programs will often let you INVERT pixels, change the number of colors allowed, and even MORPH pictures to change their shape. These are powerful programs that might already be on your computer.
Any digital image from the Internet, scanner, or camera can be converted
to a GRID of pixels. (Before you begin, use a graphic converter program
(such as GraphicConverter for MAC or PaintShopPro for PC) to convert the
image to PICT or TIF format if necessary.) Open the file using an image
processing program (NIH Image for MAC or Scion ImagePC for PC) and EXPORT
the file as TEXT. Then, the file can be opened in a spreadsheet program
such as MS EXCEL.
Alternatively, any grid of numbers can be drawn in MS EXCEL by plotting
a 3-D surface plot or by saving the data as TEXT and IMPORTing the data
into your image processing program.
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Lesson designed by the YPOP Team
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