我在MATLAB中有一张图片:
y = rgb2gray(imread('some_image_file.jpg'));
我想对它进行一些处理:
pic = some_processing(y);
找到输出的局部极大值。也就是说,所有在y
中比它们的邻居都要大的点。
我似乎找不到一个很好的MATLAB函数来完成这个任务。我能想到的最好的方法是:
[dim_y,dim_x]=size(pic);
enlarged_pic=[zeros(1,dim_x+2);
zeros(dim_y,1),pic,zeros(dim_y,1);
zeros(1,dim_x+2)];
% now build a 3D array
% each plane will be the enlarged picture
% moved up,down,left or right,
% to all the diagonals, or not at all
[en_dim_y,en_dim_x]=size(enlarged_pic);
three_d(:,:,1)=enlarged_pic;
three_d(:,:,2)=[enlarged_pic(2:end,:);zeros(1,en_dim_x)];
three_d(:,:,3)=[zeros(1,en_dim_x);enlarged_pic(1:end-1,:)];
three_d(:,:,4)=[zeros(en_dim_y,1),enlarged_pic(:,1:end-1)];
three_d(:,:,5)=[enlarged_pic(:,2:end),zeros(en_dim_y,1)];
three_d(:,:,6)=[pic,zeros(dim_y,2);zeros(2,en_dim_x)];
three_d(:,:,7)=[zeros(2,en_dim_x);pic,zeros(dim_y,2)];
three_d(:,:,8)=[zeros(dim_y,2),pic;zeros(2,en_dim_x)];
three_d(:,:,9)=[zeros(2,en_dim_x);zeros(dim_y,2),pic];
然后查看第三维度中的最大值是否出现在第一层(即:three_d(:,:,1)
):
(max_val, max_i) = max(three_d, 3);
result = find(max_i == 1);
有没有更优雅的方式来做这件事?这似乎有点笨拙。