写一段不使用的v1feat库的基于SIFT的MATLAB图像配准拼接程序

以下是一个基于SIFT的MATLAB图像配准拼接程序，不使用v1feat库：

% 读入两张需要拼接的图像
img1 = imread('image1.jpg');
img2 = imread('image2.jpg');

% 将图像转换为单通道图像
gray1 = rgb2gray(img1);
gray2 = rgb2gray(img2);

% 使用SIFT算法提取图像的特征点和描述子
points1 = detectSURFFeatures(gray1);
points2 = detectSURFFeatures(gray2);
[features1, validPoints1] = extractFeatures(gray1, points1);
[features2, validPoints2] = extractFeatures(gray2, points2);

% 对两张图像的特征点进行匹配
indexPairs = matchFeatures(features1, features2);

% 选取匹配点对
matchedPoints1 = validPoints1(indexPairs(:, 1));
matchedPoints2 = validPoints2(indexPairs(:, 2));

% 计算图像变换矩阵
[tform, inlierPoints1, inlierPoints2] = estimateGeometricTransform(matchedPoints1, matchedPoints2, 'affine');

% 对图像进行配准
outputView = imref2d(size(img1));
panorama = imwarp(img2, tform, 'OutputView', outputView);

% 将两张图像拼接在一起
panorama = max(img1, panorama);

% 显示拼接后的图像
imshow(panorama);