
Point, Line, and Edge Detection É 399
>> g = imfilter(f,w2); >> g = imfilter(f,w4);
>> figure,imshow(g) >> figure,imshow(g)
Figure 13.31 Detection of lines at +45°
Figure 13.32 Detection of horizontal lines
Figure 13.33 Detection of lines at -45°
Figure 13.34 Detection of vertical lines
13.4.3 Edge Detection
An image is nothing but a 2-D function of pixel locations (x, y) which assigns a unique intensity
value to each pixel (x, y). Pixel locations, however, are not continuous values but discrete integers.
Edge detection is done by detection of intensity discontinuity in the image.
Figure 13.30 Test image “lines”
M13_PROGRAMMING IN MATLAB_4811_CH13.indd ...