# 数据库代写 | COMP 3005 Assignment #3

I: Edge Detection using Multiscale LOG Detectors

Find all the edges in an image of your choice using multiscale LOG filters, i.e., 2G . Specifically, you need to implement the following:

(1) Blur the image with Gaussian filters (i.e., G) at several different scales (e.g., 2,8,16 ). Show the blurred images to illustrate the multiscaleidea.

(2) Apply LOG filters (2G) with the scales you choose in (1) to detect edges.

a) Show the output images filtered by 2G ; [Note that there are positive and negative values. Hence you shall display zero value in gray (128).]

b) Display the LOG-filtered images with positive values in white (255) and negative in black (0);

c) Display the zero-crossings.

d) (Bonus – 5 points) Combine the multiscale zero-crossings to obtain the final edge map.

II: Edge Detection using Canny Edge Detectors

Find all the edges in an image of your choice using Canny edge detectors. Specifically, you need to implement the following:

(1) Blur the image with Gaussian filters (i.e., G) at several different scales (e.g., 2,8,16 ). Show the blurred images to illustrate the multiscaleidea.

(2) Apply Canny edge detectors with the scales you choose in (1) to detect edges.

a) Show the magnitude and angle, respectively, of the gradient images after applying Canny edge filters (i.e., the 1stderivative ofGaussians);

b) Display the edges before and after non-maximum suppression.

c) Display the final edge maps after edge linking (or the double-thresholding technique).

You shall write and hand in your report and implementation codes. In your project report, please describe your approaches, experimental results and discussions in detail.

IMPORTANT:

(1) DO NOT use the MATLAB built-in function “edge(I, ‘log’, …)” & “edge(I, ‘zerocross’, …)” for this project. You shall implement your own LOG edge detectors using other Matlab built-in functions. You can check your results with that of “edge(I, ‘log’, …)” & “edge(I, ‘zerocross’, …)” for comparison.

(2) DO NOT use the MATLAB built-in function “edge(I, ‘canny’, …)” for this project. You shall implement your own Canny edge detectors using other Matlab built-in functions. You can check your results with that of “edge(I, ‘canny’, …)” for comparison.

(3) For the discussion, it is suggested to compare your experimental results with those from other edge detectors in Matlab, i.e., “edge(I, …)”.