Imaging

Background:  

Spacecraft, such as the Mars Global Surveyor and the Hubble Space Telescope, send images to the Earth by radio signals. These radio signals transmit a long string of numbers that tell the brightness and location of each pixel in an image. Pixels are small dots of color or light. You can see pixels by looking closely at your computer or TV screen. Computers retranslate the numbers into pixels to form an image.  Images of Mars, such as the one at left, are studied to determine suitable landing sites that will meet a rover's safety, communication, and power needs. To be acceptable for scientific experiments testing an early warm and wet climate hypothesis, the site should exhibit surface features showing accessibility to rocks, water channels, and layered deposits.

Activity: 
Students can simulate the process of encoding/decoding pictures of a planet by converting a string of numerical data into the image of an object in space. 

Materials:

Procedure:

  1. Divide the class into 10 teams.
  2. Give each team a strip of graph paper 28 squares wide by 4 squares high. Each 28 x 4 grid will compose one portion of the picture to be deciphered from space.
  3. Give each team a set of "data stream" numbers from the list below. Each number in the data stream represents the brightness of one pixel.
  4. Begin to encode the image by placing the first digit of the data stream in the upper left box in the 28 x 4 strip of graph paper.  Place the second number in the data stream in the box to the right on the same line.  Place numbers in the boxes until the first line is complete.  Fill in the second, third, and fourth lines of the grid, from left to right, until the entire grid is filled.
  5. The four sheets of colored paper correspond to the numbers sent down by the spacecraft with 0 representing white, 1 yellow, 2 orange, and 3 red.  Cut the pieces of paper into 1/4" squares.  Glue the appropriate colored square over each correspondingly numbered grid box. 
  6. Glue each 28 x 4 strip onto a large piece of paper to create the full image.

Data Streams:

Team #1
0 0 0 0 0 0 0 1 1 1 0 0 1 1 0 0 0 1 1 2 1 1 1 2 3 3 3 3
0 0 0 0 0 1 0 0 1 2 1 1 1 1 1 0 0 1 2 0 2 2 3 3 3 3 3 3
0 0 0 1 0 0 1 0 1 2 2 1 1 1 1 1 1 1 2 0 2 3 3 3 3 3 3 3
0 0 0 1 0 0 0 0 1 1 2 2 1 1 1 1 1 1 2 2 2 3 3 3 3 3 3 3

Team #2
0 0 1 1 1 0 0 0 0 0 2 2 1 1 0 1 1 1 2 2 2 3 2 3 3 3 3 3
0 1 1 2 2 1 0 0 1 0 2 2 1 1 0 1 1 1 1 1 2 2 2 3 3 3 3 3
0 1 2 2 2 2 1 0 0 1 0 2 2 2 1 1 1 1 1 1 2 2 2 3 3 3 3 3
0 1 2 1 2 2 2 2 0 1 0 1 1 1 1 1 2 1 1 1 2 1 2 2 3 3 3 3

Team #3
1 2 1 1 1 1 1 2 2 1 1 1 2 2 1 1 2 1 1 0 2 2 1 2 2 3 3 3
1 2 1 1 1 1 1 1 2 2 1 1 1 2 2 1 1 1 0 1 2 2 1 2 2 3 3 3
1 2 1 0 2 2 1 1 2 2 2 1 1 2 2 2 1 1 1 1 1 1 2 2 2 3 3 3
1 2 1 0 2 2 2 2 2 2 2 1 2 1 2 2 1 1 1 1 1 1 1 2 2 3 3 3

Team #4
0 2 1 0 2 2 2 2 2 2 2 2 1 1 1 2 1 2 2 2 1 1 2 1 2 2 3 3
0 1 2 0 1 1 2 2 3 2 2 2 2 1 1 1 2 2 1 1 2 1 2 1 2 2 3 3
0 0 2 1 1 2 2 2 3 3 2 2 3 2 1 1 2 1 0 0 1 2 1 1 2 2 3 3
0 0 2 1 1 2 2 3 3 3 3 2 3 2 1 2 1 0 0 0 0 1 2 1 2 2 2 3

Team #5
1 0 1 2 1 1 1 2 3 3 3 2 3 2 1 2 2 0 0 0 0 0 2 1 1 2 2 3
1 0 1 2 1 1 1 2 3 3 3 3 2 3 1 2 2 0 0 0 0 0 1 2 2 2 2 3
2 1 1 1 2 1 2 1 2 3 3 3 2 3 2 2 2 1 0 0 0 0 0 2 1 2 2 3
2 1 1 1 2 1 1 1 2 3 3 3 3 3 3 2 2 2 1 0 0 0 0 1 2 2 2 3

Team #6
0 2 1 0 1 2 1 1 2 2 3 3 3 3 3 2 1 2 2 1 0 0 0 1 2 3 1 3
0 2 2 0 0 2 2 1 1 2 2 2 2 2 3 2 1 2 2 2 1 0 0 1 2 3 3 3
0 2 1 1 0 0 2 2 2 2 2 2 2 3 3 2 1 2 1 2 2 2 2 2 2 2 3 3
1 0 1 2 1 0 0 2 2 2 2 2 3 2 3 2 1 2 2 2 2 2 2 2 2 2 2 3

Team #7
2 0 0 1 2 1 0 1 2 2 3 3 3 3 3 2 1 2 2 1 1 1 2 2 2 3 3 2
2 3 0 0 1 2 1 0 1 1 2 3 3 3 3 2 0 1 2 2 1 2 1 1 2 3 3 2
3 2 1 0 0 0 1 2 2 2 2 3 2 3 3 2 0 1 1 2 1 2 1 2 2 3 3 3
3 2 2 1 1 1 0 0 1 2 2 2 1 2 2 1 0 0 1 1 1 1 2 2 2 3 3 3

Team #8
3 2 2 2 2 2 2 1 0 1 2 3 1 2 2 2 1 0 1 1 2 2 2 2 2 3 3 3
3 3 2 1 2 2 1 2 1 0 0 1 0 1 1 2 1 0 1 1 2 2 3 2 2 3 3 3
3 3 2 1 1 2 2 1 1 0 0 0 0 1 1 1 1 0 0 1 1 2 2 2 3 2 3 3
3 3 3 1 0 1 2 2 2 1 1 0 2 1 1 1 1 0 0 0 1 2 1 2 1 3 2 3

Team #9
3 3 3 1 0 1 2 2 2 1 1 1 2 1 2 1 1 1 0 0 1 1 2 2 1 3 3 3
0 0 0 1 0 1 2 0 0 0 0 0 2 1 1 1 1 1 0 0 1 1 2 2 1 3 3 3
3 3 3 2 0 1 2 0 0 0 0 0 1 2 1 0 2 1 0 0 1 1 2 2 2 2 3 2
3 3 3 2 1 1 0 0 0 0 1 0 1 1 1 1 2 1 0 0 1 1 2 1 2 3 3 2

Team #10
2 3 2 3 2 1 0 0 0 0 1 1 1 2 2 2 1 1 1 0 0 1 2 2 2 2 2 2
2 3 2 3 2 1 1 0 0 1 1 1 1 1 2 2 2 2 2 1 0 1 1 2 2 2 2 2
2 3 3 2 2 1 2 2 2 2 1 1 1 1 1 2 2 1 2 1 0 1 1 2 1 2 2 2
2 3 3 2 2 1 1 1 1 0 1 1 1 1 2 2 2 2 2 2 0 1 1 2 2 2 2 2

Analysis:

Once assembled, your image should look similar to the one shown at right. Do you recognize it? It is a photograph of Jupiter's Great Red Spot taken by Voyager 1. Each team used 112 pixels to create their data strip. The entire image is composed of 1120 pixels with four shades of color. True images from space are composed of millions of pixels with thousands of shades of color. This makes for a much clearer, smoother picture, but it requires large, fast computers to process the information.

Credits:

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