转自阿须数码，用MATLAB实现MPEG中的 ZIG-ZAG 扫描。觉得有点研究价值，实现的方法也很巧妙。

下面给一个参照MPEG提供的方法：

＝＝＝

function b=zigzag(a)

% 这是参照 University of California 提供的 MPEG 源代码的基础上编制的。

% Copyright (c) 1995 The Regents of the University of California.

[n,m]=size(a);

if(n~=8 & m~=8)

error(‘Input array is NOT 8-by-8’);

end

% Set up array for fast conversion from row/column coordinates to

% zig zag order. 下标从零开始，因为是从MPEG的C代码拷贝过来的

zigzag = [ 0, 1, 8, 16, 9, 2, 3, 10, …

17, 24, 32, 25, 18, 11, 4, 5, …

12, 19, 26, 33, 40, 48, 41, 34, …

27, 20, 13, 6, 7, 14, 21, 28, …

35, 42, 49, 56, 57, 50, 43, 36, …

29, 22, 15, 23, 30, 37, 44, 51, …

58, 59, 52, 45, 38, 31, 39, 46, …

53, 60, 61, 54, 47, 55, 62, 63];

zigzag = zigzag + 1;% 下标加1，符合MATLAB的下标习惯

aa = reshape(a,1,64); % 将输入块变成1×64的向量

b = aa(zigzag); % 对 aa 按照查表方式取元素，得到 zig-zag 扫描结果

＝＝＝

程序运行结果：

?a=magic(8)

a =

642361606757

955541213515016

1747462021434224

4026273736303133

3234352928383925

4123224445191848

4915145253111056

858595462631

?b=zigzag(a)

b =

Columns 1 through 12

649235517404754616012

Columns 13 through 24

4626324134272013675121

Columns 25 through 36

37352349815222936435057

Columns 37 through 48

164230284414585952453831

Columns 49 through 60

2433391953541118254810

Columns 61 through 64

6263561