Preprocessing on small images

[pabloromeu]

trafficstars

Hi again,

I have been playing around with some small images of text to check whether I could recognize some text on them, although I retrained the NN, tweaked some parameters... But no luck. I think it might be the preprocessing algorithm that lead to a non-readable text.

My original image:

What SwiftOCR debug says:

Maybe it is the size of the image?

[NMAC427]

First of all this image is way to small. Try to get a higher resolution image. Another problem is, that the characters are touching the edge of the image. If they are touching the edge they automatically get filtered out, so don't crop the image that much.

[pabloromeu]

Which is the minimum? What about resizing the image?

[NMAC427]

I would say each character should be at least 20 x 20 px large. You can try to resize the image as long as the characters aren't touching each other. Good luck.

[NMAC427]

I've scaled up the image to about twice its original size and added a 5px border. It got all bounding boxes correct except for the i.