char_recognition.m

function piece_infos = char_recognition(im_board_top_down)

r = load('golden_row_locs.mat');
r = r.r;

c = load('golden_col_locs.mat');
c = c.c;


delta = 70;
[height, width, ~] = size(im_board_top_down);
%figure;

%refs_black = load('chess_pieces_ref_black.mat');
%refs_black = refs_black.chess_piece_refs;
%refs_red = load('chess_pieces_ref_red.mat');
%refs_red = refs_red.chess_piece_refs;
refs=load('chess_piece_refs.mat');
refs = refs.chess_piece_refs;

start_i = 1;
start_j = 1;
end_i = numel(r);
end_j = numel(c);

for j = start_j:end_j             %列
    for i = start_i:end_i         %行
        h = r(i);
        w = c(j);
        im_piece = im_board_top_down(h-delta:h+delta,w-delta:w+delta,:);
        %subplot(end_i,end_j,(i-1)*end_j+j);
        %imshow(im_piece);
        [centers, radii, metric] = imfindcircles(im_piece,[45 55],'Sensitivity', 0.95);
        if numel(radii)
            im_center = [delta+1 delta+1];
            im_centers = repmat(im_center, [numel(radii) 1]);
            dists = sqrt(sum((im_centers-centers).^2,2));
            [val, idx] = min(dists);
            centersStrong = centers(idx,:);
            radiiStrong = radii(idx);
            metricStrong = metric(idx);
            dist = dists(idx);
            
            %test centers
            %为了显示效果，未加“;”
            
            real_centers{i,j}=[w-delta+centers(1),h-delta+centers(2)]
            
            %此处real_centers上所在位置的为golden视角图中像素值
            
            
            if dist < radiiStrong*1.3
                %viscircles(centersStrong, radiiStrong,'EdgeColor','b');
                im_piece_gray = rgb2gray(im_piece);
                [height_piece,width_piece] = size(im_piece_gray);
                im_mask_gray = zeros(height_piece, width_piece);
                for k = 1:height_piece
                    for l = 1:width_piece
                        pt = [l, k];
                        dist = sqrt(sum((pt-centersStrong).^2));
                        if dist <= radiiStrong
                            im_mask_gray(k,l) = 1;
                        end
                    end
                end
                im_mask = repmat(im_mask_gray, [1 1 3]);
                im_piece_masked = im_piece.*im_mask;
                match_max = 0;
                for refs_key_cell = refs.keys;
                    refs_key = refs_key_cell{1};
                    im_ref = refs(refs_key);
                    sift_result = sift_match(im_ref, rgb2gray(im_piece_masked));
                    if sift_result.ransac > match_max
                        match_max = sift_result.ransac;
                        match_key = refs_key;
                        %match_color = 'black';
                    end
                end
                
                
                if match_max > 0
                    piece_infos(i, j).name = match_key;
                    %piece_infos(i, j).centers=real_centers{i,j};
                    %piece_infos(i, j).color = match_color;
                    %piece_infos(i, j).im = im_piece_masked;
                else
                    piece_infos(i, j).name = 'none';
                    %piece_infos(i, j).color = 'none';
                    %piece_infos(i, j).im = [];
                end
                %                     piece_infos(i, j)
            end
        end
    end
end
end