Algoritma Contrast, Brightness, dan Histogram pada MATLAB

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Pengamatan menggunakan MATLAB

Gambar Sampel

Resolusi 768 X 1366 Pixel

Max     = 255
Min      = 0

Mean   = 122.6721

Standar Deviasi  = 89.4777

1.         Contrast

1.1.   Algoritma yang digunakan

clc;        % Clear command window. clear all;      close all;   % Read data RGB = imread('matahari.jpg'); subplot(2, 2, 1); image(RGB); title('Gambar Asli');  newRange = 50;  %// choose the new maximum. (new minimum always at 0.0) imgMin = double(min(RGB(:))); imgMax = double(max(RGB(:))); RGB = (RGB - imgMin) / (imgMax - imgMin) * newRange; subplot(2, 2, 2); image(RGB); title('Constras = 50');

newRange = 150;  %// choose the new maximum. (new minimum always at 0.0) imgMin = double(min(RGB(:))); imgMax = double(max(RGB(:))); RGB = (RGB - imgMin) / (imgMax - imgMin) * newRange; subplot(2, 2, 3); image(RGB); title('Constras = 150');  newRange = 200;  %// choose the new maximum. (new minimum always at 0.0) imgMin = double(min(RGB(:))); imgMax = double(max(RGB(:))); RGB = (RGB - imgMin) / (imgMax - imgMin) * newRange; subplot(2, 2, 4); image(RGB); title('Constras = 200');

1.2.   Tampilan Output

Tampilan Contrast

2.         Brightness

2.1.   Algoritma yang digunakan

clc;     % Clear command window. clear all; close all; % Variabel Konstan x=1366; % Panjang Pixel y=768; % lebar Pixel %mengambil data gambar gambar = imread('matahari.jpg'); subplot(2, 2, 1); image(gambar); title('Gambar Asli'); %untuk mengatur konsentrasi brightness brigthVal = 50; for i=1:y     for j=1:x                      %manipulasi matrix untuk memberikan brightess         img(i,j,1) = gambar(i,j,1) + brigthVal;         img(i,j,2) = gambar(i,j,2) + brigthVal;         img(i,j,3) = gambar(i,j,3) + brigthVal;     end    end    subplot(2, 2, 2); %menampikan gambar hasil manipulasi image(img); title('Brightness = 50'); brigthVal = 150; for i=1:

for j=1:x                      %manipulasi matrix untuk memberikan brightess         img(i,j,1) = gambar(i,j,1) + brigthVal;         img(i,j,2) = gambar(i,j,2) + brigthVal;         img(i,j,3) = gambar(i,j,3) + brigthVal;     end    end    subplot(2, 2, 3); %menampikan gambar hasil manipulasi image(img); title('Brightness = 150'); brigthVal = 200; for i=1:y     for j=1:x                      %manipulasi matrix untuk memberikan brightess         img(i,j,1) = gambar(i,j,1) + brigthVal;         img(i,j,2) = gambar(i,j,2) + brigthVal;         img(i,j,3) = gambar(i,j,3) + brigthVal;     end    end    subplot(2, 2, 4); %menampikan gambar hasil manipulasi image(img); title('Brightness = 200');

2.2.   Tampilan Output.

Tampilan Brightness

3.         Histogram

3.1.   Algoritma yang digunakan

clc;        % Clear command window.

clear all;     

close all;

% Read in standard MATLAB color demo image.

rgbImage = imread('matahari.jpg');

[rows columns numberOfColorBands] = size(rgbImage);

subplot(2, 2, 1);

imshow(rgbImage, []);

set(gcf, 'Position', get(0,'Screensize')); % Maximize figure.

title('Gambar Asli');

% Extract the individual color planes.

redPlane = rgbImage(:, :, 1);

greenPlane = rgbImage(:, :, 2);

bluePlane = rgbImage(:, :, 3);

% Let’s get its histograms.

[pixelCountR grayLevelsR] = imhist(redPlane);

subplot(2, 2, 2);

bar(pixelCountR, 'r');

xlim([0 grayLevelsR(end)]); % Scale x axis manually.

title('Histogram of Red Plane');

[pixelCountG grayLevelsG] = imhist(greenPlane);

subplot(2, 2, 3);

bar(pixelCountG, 'g');

xlim([0 grayLevelsG(end)]); % Scale x axis manually.

title('Histogram of Green Plane');

[pixelCountB grayLevelsB] = imhist(bluePlane);

subplot(2, 2, 4);

bar(pixelCountB, 'b');

xlim([0 grayLevelsB(end)]); % Scale x axis manually.

title('Histogram of Blue Plane');

i = imread('matahari.jpg');

j = rgb1gray(i);

k = rgb2gray(i);

l = rgb3gray(i);

subplot(2,2,1),imshow(i);

subplot(2,2,2),imshow(j);

subplot(2,2,3),imhist(k);

subplot(2,2,4),imhist(l);

3.2.   Tampilan Output

Tampilan Histogram