Unordered point set ordering

版本 2.0.3 (58.8 KB) 作者: cui,xingxing
Unordered point set ordering
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更新时间 2025/3/4

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基于非棋盘网格相机标定点自动顺序排序算法
具体算法解析请参阅References博客介绍。适用于绝大部分应用场景，支持畸变无序角点，非均匀分布的角点排序。
Example 1:
Step1, 人工制造6*10个投影变换点，并打乱排列顺序
pattern = [6,10];% 标定点模式，m*n个点
[X,Y] = meshgrid(1:pattern(2),1:pattern(1));
A = [-2.7379 0.7426 0
0.2929 -0.7500 0
0.0100 -0.0500 1.0000];% 手工设定的透视变换矩阵
coordates = [X(:),Y(:),ones(length(X(:)),1)]';
new_coords = A*coordates;
new_coords = new_coords./new_coords(3,:);
% 制造打乱顺序的点集，数字表示坐标唯一编号
new_coords = new_coords(1:2,:)';
n = size(new_coords,1);
randidxs = randperm(n);
unorder_pts = new_coords(randidxs,:);
% 无序点集
figure('Units', 'Normalized', 'OuterPosition', [0, 0.04, 1, 0.96]);
hold on;
plot(unorder_pts(:,1),unorder_pts(:,2),'r.','MarkerSize',20);
text(unorder_pts(:,1),unorder_pts(:,2),string(1:n));
grid on
title('unordered points')
Step2,算法排序
%% 默认从"下到上(y递增)，从左到右(x递增)"排序
orderedPts = CalibSort2(unorder_pts,pattern);
Step3, 绘制排序好后的点
figure('Units', 'Normalized', 'OuterPosition', [0, 0.04, 1, 0.96]);
hold on;
plot(orderedPts(:,1),orderedPts(:,2),'b.-',MarkerSize=20)
text(orderedPts(:,1),orderedPts(:,2),string(1:prod(pattern)))
grid
title('ordered points')
上述排序好的蓝色点默认是"x递增,y递增"排序的，即"从左到右，从下到上"的排序，如果想要得到”从左到右，从上到下“的排序，仅对输出的第2个参数index操作即可，尽量不要对源代码函数"CalibSort2.m"内部实现进行修改。
比如仍然对上述点排序，要求"从左到右，从上到下":
[~,index] = CalibSort2(unorder_pts,pattern);% 只要对输出的第二个参数index操作即可
%% 从"上到下(y减小)，从左到右(x增大)"
index_up2down = reshape(index,[pattern(2),pattern(1)]); % 内存连续
index_up2down = fliplr(index_up2down);
orderedPts = unorder_pts(index_up2down(:),:);
%% 绘图
figure('Units', 'Normalized', 'OuterPosition', [0, 0.04, 1, 0.96]);
hold on;
plot(orderedPts(:,1),orderedPts(:,2),'b.-',MarkerSize=20)
text(orderedPts(:,1),orderedPts(:,2),string(1:prod(pattern)))
grid
title('ordered points')
Example2
对实际有畸变的图像无序格点排序：
imds = imageDatastore("data/gopro*.jpg");
load data/gridPointsData.mat
pattern = [6,9]; % 6 rows,9 cols grid points
randIdxs = randperm(prod(pattern));
for idx = 1:length(imds.Files)
img = readimage(imds,idx);
figure('Units', 'Normalized', 'OuterPosition', [0, 0.04, 1, 0.96]);
tiledlayout(1,2,"TileSpacing","none","Padding","tight")
nexttile;
imshow(img);
hold on;
unorder_pts = [imagePoints(randIdxs,1,idx),imagePoints(randIdxs,2,idx)];
plot(unorder_pts(:,1),unorder_pts(:,2),'r.',MarkerSize=20);
text(unorder_pts(:,1),unorder_pts(:,2),string(1:prod(pattern)));
title("unordered points")
% 格点排序
orderedPts = CalibSort2(unorder_pts,pattern);
nexttile;
imshow(img);
hold on;
plot(orderedPts(:,1),orderedPts(:,2),'b.-',MarkerSize=20);
text(orderedPts(:,1),orderedPts(:,2),string(1:prod(pattern)));
title("ordered points")
end
Example3
对April Grid网格角点排序：
aprilGridImg1 = imread("data/leftAprilGrid.jpg");
aprilGridImg2 = imread("data/rightAprilGrid.jpg");
imgs = {aprilGridImg1,aprilGridImg2};
load data/AprilGridPointsData.mat
pattern = [12,12]; % 12 rows,12 cols grid points
randIdxs = randperm(prod(pattern));
for idx = 1:length(imgs)
img = imgs{idx};
figure('Units', 'Normalized', 'OuterPosition', [0, 0.04, 1, 0.96]);
tiledlayout(1,2,"TileSpacing","none","Padding","tight")
nexttile;
imshow(img);
hold on;
unorder_pts = [imagePoints(randIdxs,1,idx),imagePoints(randIdxs,2,idx)];
plot(unorder_pts(:,1),unorder_pts(:,2),'r.',MarkerSize=20);
text(unorder_pts(:,1),unorder_pts(:,2),string(1:prod(pattern)));
title("unordered points")
% 格点排序
orderedPts = CalibSort2(unorder_pts,pattern);
nexttile;
imshow(img);
hold on;
plot(orderedPts(:,1),orderedPts(:,2),'b.-',MarkerSize=20);
text(orderedPts(:,1),orderedPts(:,2),string(1:prod(pattern)));
title("ordered points")
end
References
基于非棋盘网格相机标定点自动顺序排序算法解析

引用格式

cui,xingxing (2025). Unordered point set ordering (https://www.mathworks.com/matlabcentral/fileexchange/106960-unordered-point-set-ordering), MATLAB Central File Exchange. 检索时间: .

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版本 已发布 发行说明
2.0.3

1. 同步更新github文档，以GitHub发布为准
2.0.2

1. 移动到github开源，地址：https://github.com/cuixing158/grid-points-sort
2.0.1

1. 增加示例，返回的点顺序按照用户自定义方式排序。
2.0.0

1. 移除基于规则的传统算法；
2. 改用基于凸包多边形的算法
1.0.1

1. 修复中文字体乱码，改用UTF-8编码
2. 增加测试数据
1.0.0