3.5. IMPLEMENTATION OF EDGE
DETECTION.
I n this section, implementation was based on two different
operators such as:
Sobel operators and Prewitt operators. These two operators are
used in writing program, which were basically used in processing of digital
images. Here is the whole program:
|
Writeable commands
|
Results obtained.
|
|
I=imread('dushime.jpg');
figure, imshow(I), title('original image');
|
|
|
rgb2gray('dushime.jpg');
newmap=rgb2gray(I);
figure, imshow(newmap),title('gray image');
|
|
|
BWs=edge(newmap, 'sobel', (graythresh(newmap) * .1));
figure, imshow(BWs), title('binary gradient');
|
|
|
Se90=strel('line', 3, 90);
Se0=strel('line', 3, 0);
BWsdil=imdilate(BWs, [Se90 Se0]);
figure, imshow(BWsdil), title('dilated gradient mask');
|
|
|
BWdfill=imfill(BWsdil,'holes');
figure, imshow(BWdfill), title('binary image with filled
holes');
|
|
|
BWnobord=imclearborder(BWdfill,4);
figure, imshow(BWnobord), title('cleared border image');
|
|
|
SeD=strel('diamond',1);
BWfinal=imerode(BWnobord,SeD);
BWfinal=imerode(BWfinal,SeD);
figure, imshow(BWfinal), title('segmented image');
|
|
|
BWoutline=bwperim(BWfinal);
segout=I;
segout(BWoutline) = 255;
figure, imshow(segout), title('outline original image');
end
|
|
The above program is used to process the JPEG format while the
following program is used to process the BMP format.
|
I=imread('nouvelle.bmp');
figure, imshow(I), title('original image');
|
|
|
rgb2gray('nouvelle.bmp');
newmap=rgb2gray(I);
figure, imshow(newmap),title('gray image');
|
|
|
BWs=edge(newmap, 'sobel', (graythresh(newmap) * .1));
figure, imshow(BWs), title('binary gradient');
|
|
|
Se90=strel('line', 3, 90);
Se0=strel('line', 3, 0);
BWsdil=imdilate(BWs, [Se90 Se0]);
figure, imshow(BWsdil), title('dilated gradient mask');
|
|
|
BWdfill=imfill(BWsdil,'holes');
figure, imshow(BWdfill), title('binary image with filled
holes');
|
|
|
BWnobord=imclearborder(BWdfill,4);
figure, imshow(BWnobord), title('cleared border image');
|
|
|
SeD=strel('diamond',1);
BWfinal=imerode(BWnobord,SeD);
BWfinal=imerode(BWfinal,SeD);
figure, imshow(BWfinal), title('segmented image');
|
|
|
BWoutline=bwperim(BWfinal);
segout=I;
segout(BWoutline) = 255;
figure, imshow(segout), title('outline original image');
end
|
|
PREWITT OPERATOR (EDGE DETECTOR).
|
% edge detection with prewitt operator
filename= 'NEW.bmp'; % the filename to be read
image = imread(filename);
Imshow(image); % display
|
|
|
rgb2gray('NEW.bmp');
newmap=rgb2gray(image);
figure, imshow(newmap),title('gray image');
|
|
|
axis('square');
colormap('gray');
sze=size(newmap);
rows = sze(1); cols = sze(2);
|
|
|
% apply prewitt
Prw_im=edge(newmap,'prewitt');
figure(2);
|
|
|
imagesc(Prw_im);
axis('square');
colormap('gray');
end
|
|
EDGE DETECTION WITH SOBEL
|
% edge detection with Sobel operator program
filename= 'NEw.bmp'; % the filename to be read
image = imread(filename);
figure,Imshow(image),title('original image'); % display
|
|
|
rgb2gray('NEW.bmp');
newmap=rgb2gray(image);
figure,imshow(newmap),title('gray image');
|
|
|
axis('square');
colormap('gray');
sze=size(newmap);
rows = sze(1); cols = sze(2);
|
|
|
% apply sobel
sob_im=edge(newmap,'sobel');
figure(2);
|
|
|
imagesc(sob_im);
axis('square');
colormap('gray');
end
|
|
COMPARISON FOR EDGE DETECTION BETWEEN SOBEL AND
PREWITT.
|
Writeable program
|
Obtainable result
|
|
% comparison for edge detection between Sobel & Prewitt
operators.
filename= 'NEW.bmp'; % the filename to be read
image = imread(filename);
figure, Imshow(image), title ('original imge') % display
|
|
|
rgb2gray('NEW.bmp');
newmap=rgb2gray(image);
figure, imshow(newmap),title('gray image');
|
|
|
axis('square');
colormap('gray');
sze=size(newmap);
rows = sze(1); cols = sze(2);
|
|
|
% apply prewitt
sob_im = edge(newmap,'sobel');
figure, imshow(sob_im), title ('sobel image');
|
Figure 3.5.a. sobel image
|
|
prw_im= edge(newmap,'Prewitt');
figure, imshow(prw_im), title('prewitt image');
|
Figure 3.5.b. prewitt image.
|
|
dif_im=double(sob_im)- double(prw_im);
figure(2);
|
|
|
imagesc(dif_im);
axis('square');
colormap('gray');
end
|
|
CHAPTER 4. RESULTS AND
DISCUSSION.
|
|
