% LECT05A.M 2/12/01 BME5002 J.G. HARRIS
echo on
clear
close all
% read in image
figure(1)
lung1=imread('lung1.jpg');
% this image is only two-dimensions
size(lung1)
pause
% now display the image
%
what is wrong with this patient?
%
what is the pixel noise?
imshow(lung1);
pause
% Now let's display a histogram equalized image
% Notice how you can no longer see some of the
%
ribs on the left side of the image
% Histogram equalization is not always a good idea!!!!!
%
why not?
figure(2)
imshow(histeq(lung1))
% IMAGE PROCESSING LECTURE 5B
% BME5002 JOHN G. HARRIS 2/12/01
% 1D filtering
chest=imread('chest.jpg','jpg');
%by default, jpeg images have 3 color bands
%we only need to take one
% (also convert the image from uint8 to double)
chest=double(chest(:,:,1));
% imagesc always works, why not use imshow?
figure(1)
imshow(chest)
colorbar
pause
imhist(chest);
pause
% must make a uint8 or a double between 0 and 1 so...
chest=chest/max(max(chest));
pause
% now imshow can be used
imshow(chest)
colorbar
pause
% imshow can take arguments of min and max grayscale values
figure(2)
1
imshow(chest,[0 .6])
pause
% can use imhist to compute histogram of a double image
figure(2)
imhist(chest)
pause
% take a vertical slice of the image
slice=chest(:,200);
figure(2)
plot(slice)
pause
%look at new definition of boxcar blurring and
%plotting function
type convplot
pause
%blur the slice
slice2=convplot(slice,ones(1,21)/21);
% IMAGE PROCESSING LECTURE 5C
% BME5002 JOHN G. HARRIS 2/12/01
% 2D filtering
chest=imread('chest.jpg','jpg');
%by default, jpeg images have 3 color bands
%we only need to take one
% (also convert the image from uint8 to double)
chest=double(chest(:,:,1));
figure(1)
imagesc(chest);
colorbar
pause
%Blurring the image with a boxcar filter
b=ones(11,11)/(11*11);
chest2=conv2(b,chest);
pause
figure(2)
imagesc(chest2)
colorbar
colormap(gray(256))
pause
%highpass filter vertical direction
b=[1 1 1; 0 0 0 ; -1 -1 -1]
chest2=conv2(b,chest);
figure(2)
imagesc(chest2)
colorbar
colormap(gray(256))
2