写一段matlab亚像素定位的代码

以下是一个简单的亚像素定位的matlab代码示例：

% 读取图像
I = imread('image.jpg');

% 提取图像边缘
E = edge(I, 'canny');

% 定义一个5x5的Sobel算子
Sx = [-1 -2 -1; 0 0 0; 1 2 1];
Sy = [-1 0 1; -2 0 2; -1 0 1];

% 使用Sobel算子计算图像中的梯度
Gx = conv2(double(I), Sx, 'same');
Gy = conv2(double(I), Sy, 'same');
Gmag = sqrt(Gx.^2 + Gy.^2);

% 使用非极大值抑制算法来抑制梯度的非峰值部分
Gdir = atan2(Gy, Gx);
Gdir(Gdir < 0) = Gdir(Gdir < 0) + pi;
Gdir = Gdir * 180 / pi;
Gdir(Gdir < 22.5 | Gdir >= 157.5) = 0;
Gdir(Gdir >= 22.5 & Gdir < 67.5) = 45;
Gdir(Gdir >= 67.5 & Gdir < 112.5) = 90;
Gdir(Gdir >= 112.5 & Gdir < 157.5) = 135;
for i = 2:size(Gmag,1)-1
for j = 2:size(Gmag,2)-1
switch Gdir(i,j)
case 0
if Gmag(i,j) <= Gmag(i,j-1) || Gmag(i,j) <= Gmag(i,j+1)
Gmag(i,j) = 0;
end
case 45
if Gmag(i,j) <= Gmag(i-1,j+1) || Gmag(i,j) <= Gmag(i+1,j-1)
Gmag(i,j) = 0;
end
case 90
if Gmag(i,j) <= Gmag(i-1,j) || Gmag(i,j) <= Gmag(i+1,j)
Gmag(i,j) = 0;
end
case 135
if Gmag(i,j) <= Gmag(i-1,j-1) || Gmag(i,j) <= Gmag(i+1,j+1)
Gmag(i,j) = 0;
end
end
end
end

% 使用Harris角点检测算法来检测图像中的角点
C = cornermetric(Gmag);
C = C .* E;
C(C < max(max(C))/10) = 0;
C = imdilate(C, strel('disk', 5));

% 对角点进行亚像素定位
corners = cornerpoints(C);
for i = 1:size(corners,1)
r = corners(i,1);
c = corners(i,2);
Ix = Gx(r-1:r+1,c-1:c+1);
Iy = Gy(r-1:r+1,c-1:c+1);
It = Gmag(r-1:r+1,c-1:c+1);
[u, v] = subpixel(Ix, Iy, It);
corners(i,:) = corners(i,:) + [u v];
end

% 显示结果
imshow(I);
hold on;
plot(corners(:,2), corners(:,1), 'r*');
hold off;