convertPair2GraphInfo.m

function [detections,edges ,cost_edges] = convertPair2GraphInfo(pairs)
% convert the pairs info to graph info (node, edges, costs of edges) with
% repect to the graph


% node info
node_1 = pairs.globalID1;node_2 = pairs.globalID2; node_all = [node_1;node_2]; edges_all = [node_1, node_2];
box1 = pairs.box1; box2 = pairs.box2; box_all = [box1;box2];
frame1 = pairs.frame1; frame2 = pairs.frame2; frame_all=[frame1; frame2];
det_all = double([box_all, frame_all]);
[~, ia, ~]= unique(node_all);
det_all = det_all(ia,:);
prob_edges = 1-pairs.dist;

num_frame = max(frame_all);
detections = cell(num_frame,1);
edges = cell(num_frame,num_frame);
cost_edges = cell(num_frame,num_frame);


for i = 1:num_frame
    fprintf('converting pairs info to graph info for frame %d out of %d \n', i, num_frame);
    list_i = find(frame1 == i);
    if ~isempty(list_i)
         for j = i:num_frame
            list_j = find(frame2 == j);
            if ~isempty(list_j)
                idx = intersect(list_i,list_j);
                if ~isempty(idx)
                    node_i = node_1(idx);
                    node_j = node_2(idx);
                    cur_pro = prob_edges(idx);
                    cost = log((1-cur_pro)./cur_pro);
                    edges{i,j} = [node_i, node_j] -1;
                    cost_edges{i,j} = cost;
                end
            end
         end
    end
    det_list_i = find(det_all(:,end) == i);
    if ~isempty(det_list_i)
        det_i = det_all(det_list_i,:);
        detections{i} = det_i;
    end
end

% for i =1:num_frame
%     fprintf('converting pairs info to graph info for frame %d out of %d \n', i, num_frame);
%     list_i = find(det_all(:,end) == i);
%     if ~isempty(list_i)
%         det_i = det_all(list_i,:);
%         for j = i:num_frame
%             list_j = find(det_all(:,end) == j);
%             if ~isempty(list_j)
%                 tmp_comb = [];
%                 if i==j % same person
%                     if size(det_i,1)~=1
%                         tmp_comb = nchoosek(list_i,2);
%                     end
%                 else % difference person
%                     tmp_comb = combvec(list_i',list_j')';
%                 end
%                 edges{i,j} = tmp_comb-1;
%                 cost = zeros(size(tmp_comb,1),1);
%                 for e = 1:size(tmp_comb,1)
%                     idx = intersect(find(node_1 == tmp_comb(e,1)),find(node_2 == tmp_comb(e,2)));
%                     if isempty(idx)
%                         cost(e) = 10^5; % same frame, assuming the pairs contains a full graph.
%                     else
%                         prob = prob_edges(idx);
%                         cost(e) = log((1-prob)/prob);
%                     end
%                 end
%                 cost_edges{i,j} = cost;
%             end
%         end
%         detections{i} = det_i;
%     end
% end
end