Reverse image search implementation

[FoxxMD]

I think this is a question mostly for @sgsunder

I have a working "find image based on perceptual hash" system in a project I am working on. It also does fuzzy searching for in-memory hashes.

Soon, I want to expand this to storing the hashes so I can search them later. I can do this, now, without an issue but only if I'm searching for exact hashes using simple where clauses in my main database.

I've been a long time szuru user and I remember when the project migrated from using elasticsearch (with i assume fuzzy query) to no dependencies!

From looking at the code now my rough understanding of how reverse image search is working:

• using image-match
• storing some kind of matrix generated from the image-match signature in the database
• using a special type of search (postgres only?) to search for these matrixes in the db

---

I'm trying to avoid making my project dependent on elasticsearch, if possible, so what you've done here is super relevant.

My questions:

• Can you correct/clarify what the "word" matrix for the signature is? And any other implementation details you think are important here
• Is the datatype used to store the signature data special to postgres?
• How has performance panned out with this implementation?
• Any other "gotchas" you can think of -- in general for reverse image searching or this particular implementation?
• If you could do the reverse image search implementation again, would you use the same approach?

Thanks!