[Exercises]
[Workspace]
Purpose:
The purpose of this lab exercise is to experiment with the
Roberts, Sobel, Prewitt, and Isotropic edge detectors, and compare
the results.
Activities:
-
Read the image $DIP/data/gull.kdf and display it using
operators User defined and Display Image.
-
Glyphs:Input/Output:Data Files:User defined
-
Glyphs:Visualization:Non-Interactive Display:Display Image
-
Perform edge detection by executing four different gradient
operators on the image, using the operator Gradient Operator.
Note: The results of the gradient operators can be very high at some
points, (larger than 255), so it is important to convert the input
image to an appropriate pixel data type to get the proper
results. After the gradient calculation, it is possible to clip the
values or normalize the image.
-
Glyphs:Image Proc:Spatial Filters:Gradient Operator
-
Open the Gradient Operator and select the "Square Root"
option (this will calculate the Euclidean Distance of the X and Y
gradients).
-
Glyphs:Data Manip:Data Conversion:Normalize
-
Display the results.
-
Glyphs:Visualization:Non-Interactive Display:Display Image
Exercises
-
Clip the results to 255 or normalize the results to 255. Compare
and comment.
-
Take the difference between the Sobel and Isotropic
operators. Comment on the results. In which portions of the image
should the difference between the Sobel and Isotropic results be small
or large?
Khoros Workspace
Execute the visual program c9s2detect-edges.wk
Main DIP Menu
DIP Feedback Form
Copyright © 1997-1995 KRI, ISTEC, Ramiro Jordán, Roberto Lotufo. All Rights Reserved