When understanding the SIFT algorithm, I found the following two links to explain SIFT more clearly when looking through the articles or videos of various netizens on major websites, namely:
CSDN article: Detailed explanation of SIFT algorithm_zddhub's blog-CSDN blog_sift algorithm
B station video: 6. SIFT (Scale Invariant Feature Transform)_哔哩哔哩_bilibili
Therefore, record it temporarily first, so that you can conduct detailed research when you use it in the future.