Description
The purpose of this homework is to experiment with basic edge detection
Your program should be able to do the following:
• Edge Detection [6 points]
o Add edge detection for grey level images to your choice of options. Use Prewitt operator (3×3) to
compute dx and dy, compute gradient amplitude, compute edge direction
o Your program should be able to threshold gradient amplitude given some threshold.
o Your program should
operate within specified ROIs (up to three ROIs)
generate display of the amplitude of the gradient operator as intensity image
generate binary edge image derived from amplitude of the gradient operator by thresholding
generate binary edge image by further thresholding the above output using direction information
(e.g. display only horizontal (+/- 10 degree) edges or 45 degree +/- 10 degree edges etc.)
o Test your program on some grey level images
o [Extra credit – 1 Point] Implement Prewitt (5×5) operator for directional derivatives computations, then
compute edge amplitude and direction as before, compare results with Prewitt(3×3) mask
• Color processing [4 points]
o Apply the edge detection to R,G,B components independently, then combine all three sets of edges into
one image, experiment and discuss results
o Add color edge detection by applying edge detector to the I-component (using RGB <> HSI conversion),
display amplitude and thresholded magnitude (binarized) results.
o Compare utilization of RGB vs HSI for color edge detection
o [Extra credit – 1 point] Add color-edge detection by applying Prewitt edge detection to H and S
component, display amplitude and thresholded magnitude (binarized) results.
Note one Prewit 5×5 mask (Dx), Dy is the transpose
-2 -1 0 1 2
-2 -1 0 1 2
-2 -1 0 1 2
-2 -1 0 1 2
-2 -1 0 1 2
Write a report for this assignment
• Include input and output images (use several gray level and several color images as appropriate).
• Discuss performance of grey level edge detectors on images
• Discuss performance of your edge detector on color images. Discuss performance in RGB and HSI domains.
Support your conclusions by examples.
• Make sure that you have extensive report for this assignment (not just few comments).
How to submit
• Submit paper report in class on the due date
• See TA help desk for instruction on program submission and testing.
