SUN_source_code_v1/code/scene_sun/extractFeature.m

function extractFeature(imageName,conf)

try
    im = im2double(imread(fullfile(conf.imagePath, [imageName '.jpg'])));
catch
    disp(['ERROR: cannot open image ' imageName]);
    return;
end


for featName = conf.featNames
    clear feat
    clear hists
    clear temp
    featName = char(featName);
    feat_fname = fullfile(conf.featPath, featName, [imageName '.mat']);
    if ~exist(feat_fname,'file')
        tic
        % Extraction
        [feat boxes] = feval(conf.(featName).extractFn, conf.(featName), im) ;
        
        if conf.(featName).outside_quantization
            % compute hist
            temp = getRoiHistsFeat(feat.words, conf.(featName), conf.(featName).pyrLevels, boxes, 'vocabWeights', []) ;

            % fix output format
            for li=1:length(conf.(featName).pyrLevels)
                histName = sprintf('L%d', conf.(featName).pyrLevels(li)) ;
                feat.hists.(histName) = temp{li};
            end
        end
        ssave(feat_fname, '-STRUCT', 'feat') ;
        fprintf('image %s    feature %s    time %f \n', imageName, featName, toc);
    end
end