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magwyz / pastec

Image recognition open source index and search engine
http://pastec.io
GNU Lesser General Public License v3.0
620 stars 175 forks source link

How does image resolution impact results? #64

Closed ecdeveloper closed 6 years ago

ecdeveloper commented 6 years ago

I was wondering, by indexing images with larger resolution - does is mean there are higher chances that the searcher will find a match?

Also, is there a "recommended" resolution for indexed images?

Thanks in advance.

abournier commented 6 years ago

I don't think it is necessary to set a size > to 1000px. You can test and observe the number of features extracted between a 150x150pxl, 500x500px and 1000x1000px. There will not be a huge difference, but it can depends from the kind of images. From my side, I will send them in 600x600px.

ecdeveloper commented 6 years ago

Thanks for a quick reply. I was also wondering about the numeric results (features?) I'm getting. What are those numbers actually mean? Any docs I can read in this regard?

Thanks!

abournier commented 6 years ago

More the image owns details and contrasts, and more the engine will extract features (vectors ?)... and more there will a possibility to find a positive in the index later. You can have a look there: https://arxiv.org/pdf/1710.02726.pdf

ecdeveloper commented 6 years ago

Thank you!