jpeg编码器的matlab代码

以下是一个简单的基于MATLAB的JPEG编码器的代码：

%读取图像文件
img = imread('image.jpg');

%将图像分为8x8的块
blocks = mat2cell(img, 8*ones(1,size(img,1)/8), 8*ones(1,size(img,2)/8), size(img,3));

%对每个块执行离散余弦变换(DCT)
dctBlocks = cellfun(@(block) dct2(block), blocks, 'UniformOutput', false);

%量化矩阵
quantizationMatrix = [16 11 10 16 24 40 51 61;
                      12 12 14 19 26 58 60 55;
                      14 13 16 24 40 57 69 56;
                      14 17 22 29 51 87 80 62;
                      18 22 37 56 68 109 103 77;
                      24 35 55 64 81 104 113 92;
                      49 64 78 87 103 121 120 101;
                      72 92 95 98 112 100 103 99];

%量化块
quantizedBlocks = cellfun(@(dctBlock) round(dctBlock ./ (quantizationMatrix)), dctBlocks, 'UniformOutput', false);

%编码块
encodedBlocks = cellfun(@(quantizedBlock) ZigZag(quantizedBlock), quantizedBlocks, 'UniformOutput', false);

%ZigZag扫描
function zz = ZigZag(block)
    zz = zeros(1,64);
    row = 1;
    col = 1;
    i = 1;
    while row <= 8 && col <= 8
        zz(i) = block(row,col);
        if mod(row+col,2) == 0 %偶数斜线
            if row == 8
                col = col + 1;
            elseif col == 1
                row = row + 1;
            else
                row = row + 1;
                col = col - 1;
            end
        else %奇数斜线
            if col == 8
                row = row + 1;
            elseif row == 1
                col = col + 1;
            else
                row = row - 1;
                col = col + 1;
            end
        end
        i = i + 1;
    end
end

请注意，此代码仅涵盖了JPEG编码器的一小部分，并且不包括熵编码和其他必要的步骤。因此，它不能用于完整的JPEG压缩。