数字图像处理实验

个⼈记录，刚学完数字图像处理，实践⼀下

1、读⼊⼀幅RGB图像，将其变换为灰度图像和⼆值图像，并在同⼀个窗⼝内分别显⽰原图，灰度图像和⼆值图像，分别标注图像名称。clear all

img = imread('onion.png');

img_gray = rgb2gray(img);figure;

subplot(3,1,1);imshow(img);title('原图');

subplot(3,1,2);imshow(img_gray);title('灰度图');img_bin = imbinarize(img_gray);

subplot(3,1,3);imshow(img_bin);title('⼆值图');

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2、任意读取⼀幅图像，对该幅图像进⾏灰度变化，实现图像变亮、变暗和负⽚效果。在同⼀个窗⼝内分别显⽰原图和相应的处理结果，分别标注图像名称。clear all

img = imread('onion.png');img=double(img);

img_neg = zeros(size(img));img_up = zeros(size(img));img_down = zeros(size(img));

img_neg = uint8(255-1*img); % s = L-1-rimg_up = uint8(1*img.^(2));

img_down = uint8(1*img.^(0.2));

figure;

subplot(4,1,1);imshow(img);title('原图像');

subplot(4,1,2);imshow(img_neg);title('负⽚图像');subplot(4,1,3);imshow(img_up);title('变亮图像');subplot(4,1,4);imshow(img_down);title('变暗图像');

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3、读⼊matlab内置图像pout.tif，将其⼩于30的灰度值不变，将30-150的灰度值拉伸到30-200，将150-255的灰度值压缩到200-255之间。

也可使⽤for循环，遍历图像像素，依照变换函数，逐个变换

clear all

imga = imread('pout.tif');img = imga;

imga = double(imga);img=double(img);

idx1=find(imga>=30 &imga<=150);idx2=find(imga>=150&imga<=255);img(idx1) = (img(idx1)-30 )*17/12 +30;img(idx2) = (img(idx2)-150)*55/105+200;imga = uint8(imga);img=uint8(img);figure;

subplot(2,1,1);imshow(imga);subplot(2,1,2);imshow(img);

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4、读⼊lena图像，为其随机叠加椒盐噪声，使⽤中值滤波⽅法对其进⾏图像降噪，窗⼝分别采⽤3*3,5*5,7*7。在同⼀窗⼝内依次显⽰叠加噪声的图像，和处理后图像。clear all

img = imread('D:\\Program Files\\MATLAB\\R2018a\oolbox\\images\\imdata\\lena.png');[width,height,z]=size(img);image=rgb2gray(img);noise = rand(size(img));a=0.1;b=0.2;

a1=rand(width,height)subplot(5,1,1);imshow(img);title('原图');

subplot(5,1,2);imshow(image);title('叠加椒盐噪声的图像');image_filt_33 = medfilt2(image,[3,3]);image_filt_55 = medfilt2(image,[3,3]);image_filt_77 = medfilt2(image,[3,3]);

subplot(5,1,3);imshow(image_filt_33);title('3*3窗⼝去噪后图像');

subplot(5,1,4);imshow(image_filt_55);title('5*5窗⼝去噪后图像');subplot(5,1,5);imshow(image_filt_77);title('7*7窗⼝去噪后图像');

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5、 读取matlab内置的circuit图像，对其进⾏直⽅图均衡化操作，并在同⼀窗⼝内依次显⽰原图，原图直⽅图，均衡化后的图像和均衡化图像的直⽅图。clear all

img = imread('circuit.tif');img_eq = histeq(img);figure;

subplot(2,2,1);imshow(img);title('原图');

subplot(2,2,2);imhist(img);title('原图的直⽅图');

subplot(2,2,3);imshow(img_eq(:,:,1));title('均衡化直⽅图后的图');subplot(2,2,4);imhist(img_eq);title('均衡化直⽅图');

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