帮我写一个Matlab测量水滴接触角程序

以下是一个Matlab测量水滴接触角程序的示例代码：

% 设置图像文件名和水滴半径
img_filename = 'water_drop.jpg';
drop_radius = 100; % 像素

% 读入图像并显示
img = imread(img_filename);
imshow(img);

% 选择三个点，分别表示液体表面、液滴表面和固体表面
prompt = {'选择液体表面点:', '选择液滴表面点:', '选择固体表面点:'};
dlgtitle = '选择三个点';
dims = [1 35];
definput = {'', '', ''};
answer = inputdlg(prompt, dlgtitle, dims, definput);

% 将三个点转换为像素坐标
liquid_pt = str2num(answer{1});
liquid_pt = round(liquid_pt);
liquid_pt(1) = max(1, liquid_pt(1));
liquid_pt(1) = min(size(img, 2), liquid_pt(1));
liquid_pt(2) = max(1, liquid_pt(2));
liquid_pt(2) = min(size(img, 1), liquid_pt(2));

drop_pt = str2num(answer{2});
drop_pt = round(drop_pt);
drop_pt(1) = max(1, drop_pt(1));
drop_pt(1) = min(size(img, 2), drop_pt(1));
drop_pt(2) = max(1, drop_pt(2));
drop_pt(2) = min(size(img, 1), drop_pt(2));

solid_pt = str2num(answer{3});
solid_pt = round(solid_pt);
solid_pt(1) = max(1, solid_pt(1));
solid_pt(1) = min(size(img, 2), solid_pt(1));
solid_pt(2) = max(1, solid_pt(2));
solid_pt(2) = min(size(img, 1), solid_pt(2));

% 计算水滴表面和固体表面的夹角
drop_center = drop_pt;
solid_line = [solid_pt - drop_center, 0];
drop_line = [drop_pt - drop_center, 0];
theta = acos(dot(solid_line, drop_line) / (norm(solid_line) * norm(drop_line)));
theta = rad2deg(theta);

% 将半径转换为物理长度
img_info = imfinfo(img_filename);
pixel_size = img_info.XResolution;
drop_radius = drop_radius / pixel_size;

% 输出接触角和水滴直径
fprintf('水滴直径: %.3f mm\n', 2 * drop_radius);
fprintf('接触角: %.3f 度\n', theta);

在运行程序时，需要将`img_filename`和`drop_radius`变量设置为实际图像文件名和水滴半径，然后按照程序提示选择液体表面、液滴表面和固体表面三个点。程序将计算出水滴接触角和直径，并输出到命令行窗口。