圖像壓縮編碼碼matlab實作——行程編碼

function [zipped, info] = RLEncode(vector)

[m, n] = size(vector);

%vector = vector(:)';

vector = uint8(vector(:));

L = length(vector);

c = vector(1);

e(1, 1) = c;     %e(:, 1)存放灰階

e(1, 2) = 0;     %e(:, 2)存放行程

t1 = 1;

for j = 1: L

    if((vector(j) == c))

        e(t1, 2) = double(e(t1,2)) + 1;

    else

        c = vector(j);

        t1 = t1 + 1;

        e(t1, 1) = c;

        e(t1, 2) = 1;

    end

end

zipped = e;

info.rows = m;

info.cols = n;

[m, n] = size(e);

info.ratio = m*n/(info.rows * info.cols);

clear all;

I = imread('cameraman.tif');

I = im2bw(I, 0.4);

[zipped, info] = RLEncode(I);

unzipped = RLEdecode(zipped, info);

%顯示原始圖像和經編解碼後的圖像，顯示壓縮比，并計算均方根誤差得erms=0，

%表示RLE是無失真編碼。

I2 = logical(unzipped);

subplot(121);imshow(I);

subplot(122);imshow(I2);

erms = compare(I, I2)

cr = info.ratio

whos I unzipped zipped

function unzipped = RLEdecode(zip, info)

zip = uint8(zip);

[m, n] = size(zip);

unzipped = [];

for i = 1: m

    section = repmat(zip(i, 1), 1, double(zip(i, 2)));

    unzipped = [unzipped section];

end

unzipped = reshape(unzipped, info.rows, info.cols);