PERFORMANCE ASSIGNMENT                                 Lab Seven

Density Calibrating Images

Background

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Hurricane Opal: 1995
 There will come a time when you have the real-world measurement values of a few pixels in the image but not the entire range. This is most common with satellite infrared images (temperatures), altitudes (digital elevation maps), etc. Density calibrating an image will mathematically relate the values of one pixel to other pixels.

Using the NOAA 15 infrared satellite image of hurricane Opal, shades of gray represent temperature values, you will process this image. The know temperature for pixel value 141 is 60 degrees Fahrenheit, pixel value 38 represents -68 degrees.

Procedure

    1. Download the image file in bmp format HERE by right clicking the mouse and saving the file to your image folder.

    2. Open Scion Image and using the File dropdown menu, load the image hurricane.bmp.

    3. As you move the cursor around the image you can see the the values of X, Y and Value change with the cursor,
        in the Info Box. X and Y represent the cursors location within an X-Y space. The Value represents
        the density of the grayscale on a scale of 1 to 255.

    4. Select the Analyze dropdown menu and click on Options... The Measurement Pop-up menu will appear, check
        Area, Mean Density and Perimeter/Length, click on OK.

    5. Only two pixel values are known. Click on the line selection tool and then move the cursor around until you can
        locate a pixel with the value of 141. Double click (making a line, one pixel long) on that pixel. Select the Analyze
        dropdown menu and click on Measure

    6. Repeat Step 5 for the pixel value of 38.

    7. Select the Analyze dropdown menu and click on Calibrate. Type the known values for pixel 141 and 38, 60 and
        -68 degrees respectively. Be sure to check Straight Line, type in degrees F for the units. Click OK

    8. After clicking on OK a Plot Box will appear showing the plot of the line and the equation. Note the equation
        in your data table and then close the box.

Data

Pixel
Temperature (F)
141
60
38
-60
Equation
 

Analyze

    1.