Digital Images: From Yohkoh to the Internet

  A printable version of this lesson can be found here
Overview: Written as a lesson plan for teachers, students completing this activity will learn about digital images and how satellites orbiting Earth send information and pictures to us over the Internet.

Learning Objectives:

By completing these activities over a one week period, the learner will:

Materials Needed:

Anticipatory Set (Day One):

Take pictures of students or your school and observe them on the computer (use either a digital camera or scan images taken with a conventional camera). Ask students how the picture or information to make the picture got inside the computer. Students should be shown other electronic pictures, such as daily weather satellite images. Tell students that the class is going to learn how electronic information is transferred over the Internet and displayed on computers.
 

Show students magnified images of their pictures on the computer. Extreme magnification will show that an electronic picture is composed of little squares, called picture elements or pixels. Ask students to examine the image and count the number of pixels wide various features are. For example, how many pixels wide is your face, your nose, your chair, etc.

Exploration (Day Two):

Direct students to create an image of their name by blacking-out individual squares on rectangular graph paper. There should be no shading or "half-squares" colored in. First color in the squares; second, add numbers to identify colors. Provide students an example, such as the one shown below.

Two Color Image ( 0 = White; 1 = Black)

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(rows are horizontal and columns are vertical)


Concept Introduction (Day 3):

Computers often record and transfer information using a series of ones (1) and zeros (0). This is called a "binary system." In the images that students created, a computer would often record each box or PICTURE ELEMENT (pixel) as being a zero for white and a one for black.  

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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Ask students to create a "mystery word" or "mystery picture" on graph paper and "tell" fellow student how to recreate exactly the same WITHOUT showing students the picture. Call white squares zero and black squares one. Suggest to students that they start in the upper left hand corner of the paper and read numbers (one and zeros) all of the way across the page to the end of the line, then, go back to the left side and read the second row.

Students should pay attention to, and create if possible, ways to speed up the process of telling someone how to create the picture. Speeding up this process is called FILE COMPRESSION.

Concept Application (Day 4):

Satellites send images from space to Earth by radio waves using a series of ones and zeros. In this activity students will decode an actual image from the Yohkoh satellite. The process of sending data from a telescope to the Internet is called TELEMETRY.
   

Four Color Key 

Zero = white 
One = light gray pencil 
Two = dark gray pencil  Three = black marker 

 
Divide students into four or eight NASA imaging teams. Each team needs one of four attached data sheets, a sheet of graph paper, a black marker, and a pencil. IMPORTANT: Students should read across rows, one row at a time. Encourage students to figure out ways to make the process go faster, but keep in mind it is very important to be as accurate as possible.
 

Team Two

Team One

Team Three

Team Four

Overlay the teams' images as at right with no gaps in the data. These four quadrants should combine to create an actual image of our Sun taken by the X-Ray telescope on board the NASA and Japanese Yohkoh satellite. The black spots show the most active regions of our Sun that generate X-Rays. These energetic regions are places where sunspots can often be observed. Additionally, these areas are high energy regions that release particles that can be observed on Earth as the Northern Lights.

Lesson Debriefing:

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.
 

1 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
1 1 0 0 1 0 0 1 1 0 0 1 1 1 1 0 0 1 1 0
1 1 0 0 1 0 1 0 0 1 0 1 0 0 0 0 1 0 0 1
1 0 1 0 1 0 1 0 0 1 0 1 0 0 0 0 1 0 0 1
1 0 1 0 1 0 1 1 1 1 0 0 1 1 0 0 1 1 1 1
1 0 0 1 1 0 1 0 0 1 0 0 0 0 1 0 1 0 0 1
1 0 0 1 1 0 1 0 0 1 0 0 0 0 1 0 1 0 0 1
1 0 0 0 1 0 1 0 0 1 0 1 1 1 1 0 1 0 0 1

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.
 

Attached: Four Parts of the SXT Imaging Team Pixel Map

Hand Out for Team 1, Hand Out for Team 2, Hand Out for Team 3, Hand Out for Team 4 (print as portrait)

SXT Imaging Team 01

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0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 2 2 2 1 0 0 0 0

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 2 2 2 0 0 0 0

1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 2 2 1 0 0 0 0

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0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 2 3 3 2 2 2 3 2 2 2 2 2

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 2 3 2 2 2 2 2 2 2 2 2

1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 2 2 2 2 1 2 2 2 2 1

1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 0 1 2 2 1 2 2 2 2 1 1

SXT Imaging Team 02

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1

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0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

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0 0 0 0 0 0 0 0 0 0 1 1 1 0 0 1 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 1 1 1 1 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0

0 0 0 0 0 0 1 1 1 1 1 2 0 0 0 1 1 0 0 0 1 2 2 2 2 1 1 1 1 0 0

0 0 0 0 0 1 1 1 1 1 2 1 1 1 1 1 1 1 0 1 1 2 2 2 2 2 2 2 1 1 0

0 0 0 0 0 1 1 1 1 1 2 2 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 1 1 0

0 0 0 0 1 1 1 1 1 2 2 1 2 1 1 1 2 2 2 1 2 2 2 2 2 2 2 2 2 1 0

0 0 0 1 1 1 1 1 2 2 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 2 2 1 1 0

0 0 1 1 2 2 2 2 2 2 1 1 2 1 1 1 2 2 2 2 2 2 2 3 3 2 2 2 0 0 0

0 1 1 1 2 2 2 2 2 2 1 1 1 1 1 1 2 2 2 2 2 2 3 3 2 2 1 1 0 0 0

1 1 1 1 2 2 2 2 2 2 1 1 1 0 0 1 2 2 2 2 2 2 3 3 3 3 2 2 1 0 0

0 0 1 2 1 2 2 2 2 1 0 1 0 0 0 0 1 1 2 2 2 2 3 3 3 3 3 3 2 2 2

0 0 1 2 1 2 2 2 2 0 0 0 0 0 0 1 1 1 2 1 1 1 2 2 2 2 2 3 3 3 2

0 0 1 1 1 2 2 2 2 1 0 1 1 0 0 0 1 1 2 2 1 1 1 2 2 2 2 3 3 2 2

SXT Imaging Team 03

0 0 1 1 1 2 2 2 2 1 1 1 1 1 0 0 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2

0 1 0 0 1 2 2 2 3 2 1 1 1 1 1 0 1 0 1 1 1 0 0 1 2 2 2 2 2 2 1

0 0 0 0 1 2 2 3 3 2 1 1 1 1 0 0 1 0 1 1 0 0 0 0 1 2 1 1 1 1 1

0 0 0 1 1 1 2 3 3 3 2 1 1 1 1 0 0 0 1 1 0 0 0 0 1 1 1 1 1 2 1

0 0 0 1 1 1 2 2 3 3 2 1 1 1 1 1 0 1 1 0 0 0 0 0 0 0 0 0 1 1 2

0 0 0 1 1 1 2 2 2 2 2 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1

0 0 1 1 1 1 2 2 2 2 2 2 1 2 2 0 0 0 0 0 1 0 0 0 0 0 0 1 0 1 0

0 0 0 0 0 0 1 1 2 2 2 2 2 2 1 0 0 0 0 0 1 1 0 0 0 0 0 0 1 0 0

0 0 0 0 0 0 1 1 2 2 2 2 2 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

0 0 0 0 0 1 1 2 2 2 2 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

0 0 0 0 1 1 1 2 2 2 2 2 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1

0 0 0 0 1 1 1 1 2 2 2 2 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1

0 0 0 0 1 1 1 1 2 2 2 2 2 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1

0 0 0 0 1 1 1 1 2 2 2 2 2 1 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1

0 0 0 0 0 1 1 1 2 2 2 2 2 2 1 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 1

0 0 0 0 0 0 1 1 1 2 2 2 2 2 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 1 1 2 1 1 2 2 2 2 1 1 0 1 1 1 0 1 0 0 0 0 0 0 0 0

0 0 0 0 0 0 1 1 1 2 1 1 2 2 2 2 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 1 1 1 1 2 1 1 2 2 2 2 0 0 0 0 0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 1 1 1 1 1 2 1 1 1 2 1 1 0 0 0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 2 1 1 1 0 0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 2 1 1 1 1 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0 0 0 0 0 1 2 1 2 1 1 2 1 1 1 1 1 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

SXT Imaging Team 04

1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 1 1 2 1 1 0 1 2 2 1 1

2 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 0 0 1 1 1 1 1

1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 1 1 2 1 0

1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 2 1 0

1 0 0 0 0 0 0 0 0 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 2 1 1 0 0

0 0 0 0 0 0 0 0 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 2 1 1 0 0

0 0 0 0 0 0 0 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 2 1 0 1 1 1 1 0 0

0 0 0 0 0 0 1 2 2 1 1 1 1 0 0 0 0 0 0 0 0 0 2 2 0 1 1 1 0 0 0

0 1 0 0 1 2 2 2 2 1 1 1 1 0 0 0 0 0 0 0 0 0 1 2 1 1 1 0 0 0 0

1 0 0 0 2 2 2 2 2 2 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 0 0 0 0

1 1 0 1 3 3 2 2 2 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 0 0 0 0

1 1 1 2 3 2 2 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

1 1 2 2 3 2 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

1 1 2 2 2 2 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0

1 1 2 2 2 2 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0

1 1 1 2 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0

0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Lesson designed by the YPOP Team

For questions about this lesson, please contact Tim Slater