[Exercises]
[Workspace]
Purpose:
The purpose of this lab is to experiment with the histogram
stretch technique for image contrast enhancement.
Activities:
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Read the image $DIP/data/cathedral.kdf and display it using the
operators User defined and Display Image.
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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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Determine the histogram of the image and plot it. Use operators Histogram
and Display 2D Plot.
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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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When the plot comes up, select the "Options" button, and change
the "Plot Type" to "Discrete".
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Perform a histogram stretch on the image, calculate the new
histogram and plot it. Use operators Stretch, Histogram, and Display 2D Plot.
Display the resulting contrast enhanced image using Display Image.
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Glyphs:Data Manip:Histogram Operators:Stretch
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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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Glyphs:Visualization:Non-Interactive Display:Display Image
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Change the plot type to "discrete". Compare the images and the
histograms of the original versus the histogram stretched image.
Exercises
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Perform the same experiment using images with high contrast and
with low contrast.
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Do you think an interactive histogram modification tool is a
desirable tool to have?
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Can you think of other methods to enhance the contrast of an
image?
Khoros Workspace
Execute the visual program c4s4histogram-stretch.wk
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