Basic image processing in Matlab

%% Image Creation. You have to thing reversely because background is write or 255 or true.

% size of creating image

rows = 500;

columns = 500;

% creating write image

grayImage = zeros(rows, columns, 'uint8');

grayImage(:) = 255;

%drawing shape. I am drawing equilateral triangle.

xCoords = [50 50 400]; % x1 , x2 ,x3

yCoords = [50 450 250]; % y1 , y2 , y3

mask = poly2mask(xCoords, yCoords, rows, columns); %first node(x1,y1), second node(x2,y2), third node(x3,y3)  AND  size

grayImage(mask) = 0; % or whatever value you want.

% some operations.

% we are using negatif image so that we have to think reverse

symmetry=fliplr(grayImage); %symmetry of image

intersection=bitor(grayImage,symmetry);  % like this matchingPixels = (double(grayImage) + double(symmetry)) == 0;

association=bitand(grayImage,symmetry);

%% Showing Images

figure;

ax1=subplot(2,2,1);

imshow(grayImage);

title('orjinal');

ax2=subplot(2,2,2);

imshow(symmetry);

title('symmetry');

ax3=subplot(2,2,3);

imshow(intersection);

title('intersection');

ax4=subplot(2,2,4);

imshow(association);

title('association(km player in linux :) )');

linkaxes([ax1,ax2,ax3,ax4],'xy')

%% taking a photo from webcam

clear cam

cam=webcam;

webcamlist;

cam.AvailableResolutions;

%preview(cam);

img = snapshot(cam);

closePreview(cam) % closes video stream

clear cam % also closes video stream

gray=rgb2gray(img);

imwrite(img,'img.png');

%% shows the orjinal and gray scale images

figure('Name','shows the orjinal and gray scale images');

subplot(2,1,1)

imshow(img)

title('orjinal')

subplot(2,1,2)

title('gray')

imshow(gray);

pause(1);

close('shows the orjinal and gray scale images'); % or close(n) ; n=1:inf

%% downsample by half

[rowsize, colsize]=size(gray);

Sampled2=gray(1:2:end,1:2:end);

Sampled2=imresize(Sampled2,[rowsize, colsize]);

[rowsize, colsize]=size(gray);

Sampled4=gray(1:4:end,1:4:end);

Sampled4=imresize(Sampled4,[rowsize, colsize]);

[rowsize, colsize]=size(gray);

Sampled8=gray(1:8:end,1:8:end);

Sampled8=imresize(Sampled8,[rowsize, colsize]);

[rowsize, colsize]=size(gray);

Sampled16=gray(1:16:end,1:16:end);

Sampled16=imresize(Sampled16,[rowsize, colsize]);

% imshow

figure('Name','shows downsampled images');

ax1=subplot(2,2,1);

imshow(Sampled2)

title('Sampled2')

ax2=subplot(2,2,2);

imshow(Sampled4)

title('Sampled4')

ax3=subplot(2,2,3);

imshow(Sampled8);

title('Sampled8')

ax4=subplot(2,2,4);

imshow(Sampled16);

title('Sampled16')

linkaxes([ax1,ax2,ax3,ax4],'xy')

pause(1);

%close('shows downsampled images'); %if you want to continue process use it