IMAGE Really Works

From School to the Solar System:

IMAGE can Measure Really Neat Objects Near and Far

Adapted from an activity by Cathy McQuone:

http://www.mcquone.com/

 

Table of Contents:

Note that these activities are all below, on this page. You need to print or save this page, save the tif images (see below), and download the Image program. After that, you can work offline.

Overview In this lesson, you will

Materials Needed:

Outline of Lesson
Part I - Proving IMAGE Really Works
Introduction to IMAGE
Activity 1- Learning to set a scale and measuring meter sticks to prove that IMAGE works.
Activity 2 - Learning to set a scale and measuring meter sticks to prove that IMAGE works
and measuring the length of a window at Leon High School.
 
Part II - Using IMAGE to measure known objects
Activity 3 - Measure length and height of Leon High School
Activity 4 -Using IMAGE to measure area using the RECTANGLE TOOL.
 
Part III - Using IMAGE to measure faraway objects.
Activity 5 - Using the FREEHAND TOOL to measure far away objects -
the Solar Eclipse in Tallahassee, FL Feb. 1998
 
Activity 6 - Extensions: Extending your use of IMAGE through other activities on the Internet.
Part I - Proving IMAGE Really Works

Introduction to IMAGE

IMAGE is a comprehensive image processing and analysis program which is used by scientists in astronomy, physics, biology, and more. (It was invented for the medical field.) Even though there are many features, this lesson will use only the SELECT Tools and ANALYZE in the Menu Bar. You will learn to set a scale, then measure length and area. After you master these tools, you will be ready to learn others.

First, Open IMAGE program.

The SELECT Tools should be on a long, thin window with a bunch of buttons. The ones you'll use include the RECTANGLE (dashed rectangle), ELLIPSE (dashed ellipse), POLYGON (angular closed shape), FREEHAND (heart-shaped) tools, which measure area and perimeter. You'll start with the LINE tool (the dashed one with the little arrow - not the plain line, as that just draws); this measures length.

The MAGNIFYING GLASS is used to get a closer look at a specific part of an image. It works like this. When an image has been opened, click on the Magnifying Glass tool, click on the section of the image to magnify. You will see the individual pixels enlarged. Click again and again on the image to get a closer view. Double click on the Magnifying Glass (or hold down the CNTRL or APPLE on the keyborad while clicking on the image) to return to the original view.

(Background information: The magnified view of an image shows that this is a digital image. A digital image is a set rectangular boxes called pixels arranged in rows and columns. When these boxes are arranged in a correct order, a recogizable picture is formed. Each pixel (picture element) has a specific number attached to it. Colors are assigned to each number. These numbers can have specific scientific meaning such as temperature. light, x-rays etc. IMAGE can measure distance, area, brightness, location and angles on digital images. Its editing capabilities allows scientists to analyze the image and collect significant scientific information. After you master measurement of lines and area, you can explore other features of IMAGE with the Extensions activities listes and the end of this page.)

Activity 1- Learning to set a scale and measuring meter sticks to prove that IMAGE works.

Open the Image program.

Click and hold the File menu. Choose Metersticks.tif. Metersticks were set side by side on the parking lot of Leon High School, Tallahassee, FL. You already know their length, but let's prove that image can measure them accurately.

First, in the Tools box, click on the SELECT LINE tool. Draw a line over the top meter stick. In the Menu Bar, pick ANALYZE, pull down to SET SCALE and let go of the mouse. First, change the Units to Meters by clicking and holding the Units box and scrolling up to Meters. Click in the Known box and type in 1 because we know that we are drawing over ONE meter stick.

(The Beta version of Image has a glitch. ALWAYS set the unit first, even if it's reading the right unit. THEN type in the numerical value. What you've just done: the program doesn't "know" very much about the image at first. You're telling it the scale length of one pixel. The program lets you pick a known length and mark it, and then tell it how long to scale the line you just drew. The program then "remembers" this scale, even if you zoom in and out, so any measurements you make from here on out will reflect the scale you set. You can save the image now, and it should remember the next time you open the image; I usually DON'T recommend saving now, as if you've goofed something, you'll have to go back online and get a fresh copy of the image. Later, when you're comfortable with the program, you'll be able to save calibrations with assurance.)

Now, let's measure something. Click on the SELECT LINE tool and draw over the 2 meters. Under ANALYZE, pick MEASURE. (The result should appear in the Info box, but you can also do this: Under ANALYZE, pick SHOW RESULTS. A box will appear with 3 columns: Area, Mean and Length. The Area shows that the line did cover a small, thin rectangular area but we are not interested in that information now. Ignore Mean.) Notice the Length gives a length of approximately 2 meters (Mine is 2.08 m). RIGHT!! That is what we expected.

Find the Percent of Accuracy by dividing the actual measurement by what IMAGE measured. 2/2.08 is .96 or 96%. This is a good Percent of Accuracy for our activities. (If you want to be pickier, you can zoom in and adjust the ends of the Selected Line...but there's a limit from the resolution of the image.)

Third, click on the SELECT LINE tool and draw over the 3 meters. Under ANALYZE, pick MEASURE. Under ANALYZE, pick SHOW RESULTS. The length is approximately 3 meters.

(Mine is 3.18. 3/3.18 is .94 or 94% accuracy.) What is your Percent of Accuracy?

Your Results from Activity 1

Object

Image measurement

Percent of Accuracy

2 meter sticks

   

3 meter sticks

 

 

Activity 2 - Learning to set a scale and measuring meter sticks to prove that IMAGE works and measuring the length of a window at Leon High School.

Click and hold the File menu. Choose LeonWindow.tif. Meter sticks were set side on a window of Leon High School, Tallahassee, FL. The leftmost is red, and there's also a verticle one at the right side of the window. Use these to set the scale, then measure the size of the window:

First, in the Tools box, click on the SELECT LINE tool. Draw a line over the 3 meter sticks on the window sill. In the Menu Bar, pick ANALYZE, pull down to SET SCALE and let go of the mouse. First, change the Units to Meters by clicking and holding the Units box andscrolling up to Meters. Click in the Known box and type in 3 because we know that we are drawing over Three meter sticks.

Second, click on the SELECT LINE tool and draw a line from one side of the triple window to the other. Under ANALYZE, pick MEASURE. Under ANALYZE, pick SHOW RESULTS. Indicate the Length in the box below.

 

Your Results from Activity 2

Object

Image measurement

Percent of Accuracy

Width of the triple window

  The actual measurement is 3.65 m. How accurate is IMAGE?________

Now that we know that IMAGE can measure accurately objects that can be verified, we will measure objects that cannot be verified easily: the height of Leon High School, a drain spout and the lamp post.

 
Part II - Using IMAGE to measure known objects
Activity 3: Measure length and height of Leon High School

Click and hold the File menu. Choose Leon.tif.

First, in the Tools box, click on the SELECT LINE tool. Draw a line over the width of a triple window. In the Menu Bar, pick ANALYZE, pull down to SET SCALE and let go of the mouse. First, change the Units to Meters by clicking and holding the Units box and scrolling up to Meters. Click in the Known box and type in your measurement from Activity 2.

Second, click on the SELECT LINE tool and draw a line from top of the highest roof to the base of the building. Under ANALYZE, pick MEASURE. Under ANALYZE, pick SHOW RESULTS. Indicate the Length in the box below.

Click and hold the File menu. Choose Drainspout.tif.

First, in the Tools box, click on the SELECT LINE tool. Draw a line over the width of a triple window. In the Menu Bar, pick ANALYZE, pull down to SET SCALE and let go of the mouse. First, change the Units to Meters by clicking and holding the Units box and scrolling up to Meters. Click in the Known box and type in your measurement from Activity 2.

Second, click on the SELECT LINE tool and draw a line from top of the drainspout (about the top of the window) to the bottom of the drainspout (where the grass begins). Under ANALYZE, pick MEASURE. Under ANALYZE, pick SHOW RESULTS. Indicate the Length in the box below.

Click and hold the File menu. Choose LampPost.tif. Use the directions above to set the scale and measure the height of the Lamp post. Notice that a meter stick (white line) was attached to the base. Set your scale using the meter stick.

Your Results from Activity 3

Object

IMAGE measurement

Length of Leon High School  
Highest Height of Leon High School  
Height of Drain spout  
Height Lamp post  
Width of Lamp post at base  
Challenge:
If the priceof the lamp post is $21.50 per foot, how much did it cost?

 

 

Activity 4: Using IMAGE to measure area using the RECTANGLE TOOL.

Click and hold the File menu. Choose SportsBoxFrnt.tif and SportsBoxSide.tif.

Notice that each picture has a meter stick highlighted in white. Use the meter stick to set the scale.

First, in the Tools box, click on the SELECT LINE tool. Draw a line over the meter stick. In the Menu Bar, pick ANALYZE, pull down to SET SCALE and let go of the mouse. First, change the Units to Meters by clicking and holding the Units box and scrolling up to Meters. Click in the Known box and type in 1.

Second, click on the RECTANGLE tool and draw a BOX around the Front of the Sports Box (omit the horizontal brace). To change the location of the box, just click anywhere on the image and begin again. Under ANALYZE, pick MEASURE. Under ANALYZE, pick SHOW RESULTS. Indicate the Area in the box below. Measure the area of each of the objects listed below and write the areas in the box.

Third, click and hold the File menu. Choose SportsBoxSide.tif Measure the area of the side paneling (omit the horizontal brace) and write the areas in the box.

Your Results from Activity 4

Object

IMAGE measurement

Area of Front of SportsBox  
Area of Side of SportsBox  
Area of Air Conditioner  
Area of Window  
Area of Door (Not seen)
equals twice the area of window
 
Total surface area of paneling needed to make the box
(Hint: subtract area of windows, door and air conditioner.)
 
Challenge 1: If a pint of paint will cover 50 square feet of surface area, how much paint will be needed to cover the paneling of the SportsBox?  
Challenge 2:
Return to Leon.tif. What is the surface area of the front of Leon High? How much surface area of the front of Leon is window?
 
 

 

 
Part III - Using IMAGE to measure faraway objects the Solar Eclipse in Tallahassee, FL February 1998
Activity 5: Using the FREEHAND TOOL to measure far away objects.
There was a partial eclipse of the sun during February 1998. An astronomer visiting Leon High School used his telescope to project an image of the eclipse on paper. The picture of the eclipse was scanned and converted to a TIFF image. IMAGE will be used to determine the Eclipse Magnitude (Fraction of the Sun's Diameter eclipsed) and the Eclipse Obscuration (Fraction of the sun's area eclipsed.)

Click and hold the File menu. Choose eclipse.tif.

First, in the Tools box, click on the SELECT LINE tool. To set the scale, draw a line over the diameter of the sun (make sure the line crosses the center of the sun). The dimensions of the Sun and the solar system can be found on the Internet. According to this Internet site is 1,400,000 kilometers. In the Menu Bar, pick ANALYZE, pull down to SET SCALE. First, change the Units to Kilometers by clicking and holding the Units box and scrolling up to Kilometers. Click in the Known box and type in 1400000 (DO NOT USE COMMAS. You may use scientific notation 1.4e6, the computer version of 1.4x10^6).

Second, click on the FREEHAND tool and draw around the area of the sun covered by the moon. You will have to estimate the outside dimensions of sun. Under ANALYZE, pick MEASURE.

Didn't work, did it? It's not your fault -- Image has a glitch with the freehand (heart) and some of the other area tools. To get around this, you can convert the image to a grayscale. Under the PROCESS menu, select CONVERT TO GRAYSCALE. I suggest saving this with a different file name, so that you don't accidentally write over the original. Don't use the Options: Grayscale -- that just changes the way it looks, not the actual storage of the image. Ok, now that you have a real grayscale image, check that the diameter of the sun is still the same. (Use the SELECT LINE tool, draw a line across the sun, then ANALYZE : MEASURE. If it reads something like 1.4e6, you're in business. If not, re-set the scale as instructed above.) Now use the FREEHAND tool and outline the dark area as above. You may wish to try this several times, as it's hard to keep a steady hand.

Under ANALYZE, pick SHOW RESULTS. Indicate the Area in the box below.

Third, click on the FREEHAND tool and draw around the area of the sun. You will have to estimate the outside dimensions of sun. Under ANALYZE, pick MEASURE. Under ANALYZE, pick SHOW RESULTS. Indicate the Area in the box below.

Your Results from Activity 5

Object

IMAGE measurement

Area of eclipse  
Area of Sun  
Length of diameter covered by the eclipse  
Diameter of the Sun 1,400,000 km
Eclipse Obscuration: area of eclipse divided by area of sun
 
Eclipse Magnitude: length of diameter covered by the eclipse divided by the diameter of the sun
 
 
 
Activity 6 - Extensions: Extending your use of IMAGE through activities on the Internet.

Feedback by visitors on this project project is appreciated. Send comments or questions to Mrs. Cathy McQuone: Teacher

Comments on this particular version should be sent to Elizabeth Roettger.

This is URL http://www.nthelp.com/eer/image.html, mirror site http://btc.montana.edu/ceres/Worlds/Image.html; last updated 31 May 1999, EER.