第一種，query結果的第一個不包括在內

MAP = [];
for i =1:query_frame
    old_recall = 0;
    old_precision = 1.0;
    ap = 0;
    intersect_size = 0;
    j = 0;    

    ngood = length(gnd{i});
    good_now = 0;
    ngood = ngood - 1;

    for n = 2:return_num
        if ~isempty(find(gnd{i} == query_result(i,n)))
            flag = 1
 
; % good image
            good_now = good_now+1;
        else
            flag = 0; % bad image
        end

        if flag == 1%good
            intersect_size = intersect_size + 1;
        end
        recall = intersect_size/ngood;
        precision = intersect_size/(j + 1);
        ap = ap + (recall - old_recall)*((old_precision+precision)/2
 
);
        old_recall = recall;
        old_precision = precision;
        j = j+1;
        if good_now == ngood
            break;
        end
    end
    MAP = [MAP,ap];

end
final_MAP = mean(MAP);

fprintf('CNN final_MAP %6.4f \n',final_MAP);

第二種，query結果的第一個計算在內，這樣計算出來的AP值要比第一種高

 MAP = [];
 for
 
 i = 1:query_frame
     double map;
     map = 0;
     up = 0;
     gnd_num = length(gnd{i}); 
     for j =1:return_num
         if( find(gnd{i}==query_result(i,j)))
            up = up+1;
            map = map + up/j;
         end
         if up == gnd_num
             break;
         end
     end
     map = map / gnd_num;
     MAP(i) = map;
 end
 final_MAP = mean(MAP);