Dark Channel Prior的Matlab代码

验证 Single Image Haze Removal Using Dark Channel Prior先验的MATLAB代码 

注：代码内容引自zixu1986 (Euro) 北邮人论坛

这个先验是：没有haze干扰自然景像中local patches（除了蓝天）总有一些像素的某个通道值非常低。

引起的原因是
1)局部阴影
2)很多彩色在rgb3个通道中有些通道的值很低
3)暗的物体或者表面

% a script to see the dark channels of each image

input_dir = 'banff';

block_size = 25;

file_ext = '.jpg';

% getting the filenames of the images

files = dir(input_dir);

filenames = {files.name};

for i = 1:length(filenames)

    if isempty(strfind(lower(filenames{i}), file_ext))

        continue

    end

   

    disp('.')

    read_filename = [input_dir filesep filenames{i}];

    I = imread(read_filename);

    img_size = size(I);

    % must be 3-channel color image

    if length(img_size) ~= 3 || img_size(3) ~= 3

        % warning('Should be color image!')

        continue

    end

   

    % min of each channel

    tmp = [];

    for j = 1:3

        tmp(:,:,j) = uint8(colfilt(I(:,:,j), [block_size block_size], 'sliding', @min));

    end

   

    dark_channel = uint8(min(tmp,[],3));

   

    k = strfind(lower(filenames{i}), file_ext);

    orig_name = filenames{i};

    orig_name = orig_name(1:k-1);

    save_filename = [input_dir filesep orig_name 'dc' int2str(block_size) file_ext];

    imwrite(dark_channel, save_filename);   

end