Doing it MY way!
When you build a mosaic from tons of pictures, you have to downscale the images before you can use them. This naturally means loss of information in the picture, when going from say 3200×2600 to 80×60 pixels. If you have a family photo, you wouldn’t be able to recognize the people in the photo any longer.
So what do you do then?
Sorry… I can’t show you the mosaic since it contains 100% private pictures. Maybe I’ll go download a couple of hundred pictures from Flickr and show you! I just don’t have the time right now.
Anyways, I quickly spottet a small “error” with my algorithm. Lets say you have a source image of a clear sky. After you divide the image into a grid, and scan the cells, it’s more than likely that the average color of all the cells will be the same.
First approach is to index all my photos (20.000+) to determine image resolution and average color value.
Before the average color value is calculated, the image is re sized to a width of about 50 pixels. Aspect ratio is maintained. This will improve scanning speed, as fewer pixels will be scanned, and also improve color correctness as only the visible pixels will be calculated. Once this process is done, the image is stored in a SQL Compact server database (filename, width, height, colorvalue).
I have been exploring the world of photo mosaics (see Wikipedia article), and it’s quite fascinating!