[Exercises]
[Workspace]
Purpose:
The purpose of this lab exercise is to calculate the
histogram of an image, obtain the statistical parameters of an image,
and to interpret the histogram of the image.
Activities:
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Calculate the histogram and statistics of the $DIP/data/gull.kdf image
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Read the image $DIP/data/gull.kdf and display it using the
following operators from the cantata menu
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Glyphs:Input/Output:Data Files:User defined
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Glyphs:Visualization:Non-Interactive Display:Display Image
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Connect the operators and display the image
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Get the main statistics of the $DIP/data/gull.kdf image using
the Statistics operator. Show the contents of the statistics in an ASCII
output file using the operator File Viewer. From the cantata menu
select
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Glyphs:Data Manip:Analysis & Information:Statistics
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Glyphs:Input/Output:Information:File Viewer
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Connect the output of User defined to the input of Statistics
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Connect the ASCII output of the Statistics object to the input
of the File Viewer. To determine which of the two Statistics outputs
is the ASCII output without opening he pane, place the mouse cursor
over an output arrow on the Statistics operator, and look at the
cantata status between the operator menus and the workspace. The name
associated with the output arrow will be displayed there.
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Run the Statistics operator and the File Viewer to see the
statistics of the image.
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Take the histogram of the image using the Histogram
operator. Plot the histogram using the Display 2D Plot operator. From the
cantata menus, select
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Glyphs:Data Manip:Histogram Operators:Histogram
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Glyphs:Visualization:Plot Display:Display 2D Plot
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Connect the output of User defined to the input of Histogram
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Connect the output of Histogram to the input of Display 2D Plot and run the operators.
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Repeat the steps above using the floating point
image $DIP/data/spine.kdf. Compute the histogram from 1000 to 2000 using
100 bins.
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open the User defined pane and select the $DIP/data/spine.kdf.
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open the Histogram pane and set the "Number of Bins to 100",
the "Bin Width" to 10, and the "Minimum" to 1000.
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Run the workspace. Look at the results of the statistics
calculation. The minimum value in the image is 1024 and the maximum
value is 1862, therefore so all values in the image have been included
in the histogram.
Exercises
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Display and take the histogram of the image $DIP/data/lenina.kdf.
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What are the minimum and maximum pixel values in the image?
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What can you say regarding the range of gray-level used in the digitalization of this image?
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Why is the minimum value not zero and why so many values equal to 255?
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Can you give a name to those effects?
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Display and take the histogram of the image $DIP/data/musc1.kdf.
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How many different cell populations can you find in the image?
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Are they represented clearly in the histogram?
Khoros Workspace
Execute the visual program c1s3image-stats.wk
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