Ah yeah, I recently changed the url scheme for my blog posts, from<p><pre><code> https://daniel.lawrence.lu/blog/y2025m09d21
</code></pre>
to<p><pre><code> https://daniel.lawrence.lu/blog/2025-09-21-line-scan-camera-image-processing/
</code></pre>
so maybe that's why OP didn't realize that it had already been posted recently. With the older scheme, not only is SEO bad, but it was really hard to remember which date corresponds to which blog post, and people can brute force search for my hidden (unpublished) blog posts easily.