ARMY PHOTO GALLERY

This is a picture of a random canal in Venice, rebuilt as a collection of 100 x 150 pictures of Venice and Florence.

The main step (i.e. to get from the photo to the first mosaic) is actually fairly simple: shrink the library of pictures you want to use and break the image you want to mosaic into pieces that are the same size as the shrunken pictures. Then, compare each one of these pieces, pixel-by-pixel, to each of the shrunken images and find the best match. Replace that piece with the shrunken image, lather, rinse, repeat, and voila: you've got the second image above.

You'll see a major problem, though: it tends to use the exact same picture dozens and dozens of times. To stop this, tell the computer to not use a picture within x spaces of itself, where x is an arbitrary number that works (5 is what I used here). It only took me 5 extra lines of code, but the logic took me 20 minutes to work out. This makes the third image.

You can stop here, but you'll notice the mosaic looks a little blocky, since it mostly reuses the same 5x5 squares over and over again. To fix this, I just had the computer add a random value to x above, and it smoothed out quite nicely.

That, in a nutshell, is how photo mosaics are made. There are a few more elegant ways to do it , but this is probably the simplest. Most professional programs also fade in the original photo a bit, to help define shapes and colors a bit better, but since this mosaic used so many photos, it wasn't really necessary. If you want to use larger pictures in your grid, fading the original in would probably be a good idea.

Programmed using Processing.

Amazing present I got from the great people in the office (thank you so much), a 29x19" portrait composed of about 3,000 of my photographs! (nope I didnt count them) How cool a mosaic image is that!

It is so amazing to see that each pixel that makes up this image is a photo in itself. Best gift ever, thank you guys.