This airport photograph is made of fragments of a fingerprint photograph. See the close up to see the detail.

An extreme close up of the airport and fingerprint mosaic.

What is a metapixel?

A pixel is a unit of an image matrix. It's one segment of a group of pixels like one red-green-blue rectangle that makes up a TV image. When a pixel is viewed from far enough away it blends in with the rest of the image and it looks like one continous picture just like if we are really looking at the scene unmediated by technology.

A metapixel is a group of pixels that looks like an image from a close viewing distance but becomes a part of a larger image when viewed from far enough away.

There are two pioneers in the field of human image recognition: Chuck Close and Leon Harmon.

Chuck Close is an American artist who used tiny image fragments, like dots from an airbrush to create portraits. He was doing this with a grid over a photograph and a hand-held airbrush starting in the early 1970s.

Scientists studied the images of Chuck Close and came to the conclusion that he already made by observation; that an image fragment begins to look like a smooth part of the image when it's smaller than 0.3 degrees of our field of vision. This is what makes it possible to look at a newspaper photograph and see an image instead of tiny dots. But if we enlarge the same newspaper image and the half-tone dots become larger than 0.3�, the image begins to fall apart and we see dots.

Leon Harmon was a scientist at Bell Labs in the USA. He wanted to know how simple an image can become but remain recognizable as a face. In 1973 he created the famous image of the American President Abraham Lincoln using only 252 tiles, which we now simply call pixels. It appeared in an article he wrote titled "The Recognition of Faces".

The first person to begin using a computer to make these tiled images was Rob Silvers while he was a student at MIT. He now has a company called Runaway Technology.

What Does Metapixel Do?

Metapixel and MetapixelGUI create a database of image characteristics inside the image library. When a large image is put into Metapixel each section is compared to the entries of the database. When a close match is found the corresponding image is inserted replacing a small piece of the original image. The software will go through all of the images until it replaces every section with a small image.

Making a Metapixel Library

1. The first step in making a mosaic is to decide which images you want use as metapixels or mosaic fragments and put them into one folder. This folder will be the source for you library.
2. It's faster to choose a folder full of small images like 128 or 256 pixels across but if you don't have a bunch of small images don't bother making them, since MetapixelGUI will resize the images for you anyway. The originals will only be read, not over-written so it's safe to choose a folder of your snapshots.
3. Now open up the Prepare window from the Controller menu (Command + 2) in MetapixelGUI. Choose the folder you just created as the input folder. It must be a folder containing JPEG or PNG images.
4. Choose the recursive option if you have folders within folders you want MetapixelGUI to process. Now you can choose your output library file (.mpx). Put all your libraries into one place. I use a Projects folder inside my Pictures folder.
5. If you don't want to use the default size of small images in your library you can change the pixel dimensions in this window, too. You'll be able to change the size of these images again when you make your mosaic, so just choose a size big enough to suit you. Using 128px x 96px is a good size start with.
6. You are ready to process the folder. MetapixelGUI's progress will be displayed in the box at the bottom of the window. Depending on the size and the amount of input images this step might take a long time. If you have a slow computer let it work while you do something else if you have over 10000 images to process.

The same image of the airport using a colour chart to make the mosaic metapixels.

The colour chart used to create the airport mosaic.

The original photograph of an airplane at YVR International Airport in Vancouver, Canada.

Making a Mosaic with MetapixelGUI

1. Now you can open the Toolbox (Command + 1). Choose your library file (.mpx) and your input image. This image won't be overwritten either but it will be used as a matrix for the small images.
2. Choose your filename for your save image. You can press Process now or you can fine tune the settings. One of the best aspects of Probst's software is the Antimosaic feature.
3. Think of it as a d�collage like Hains' posters ripped from walls of Paris in the 1960s. This mode doesn't use a library, instead it uses a single image made into fragments and recombined to make your output image. The examples below use this Antimosaic mode.

Extra Notes on MetapixelGUI

The library has the extension of .mpx and can be copied to a unix-like platform and used with the Probst's version of Metapixel.

The MetapixelGUI application download and source code is on our site. It will work on OS X 10.3 or later. It won't work well with older versions of OS X.

The original Metapixel source code can be downloaded from Mark Probst's website. If you are curious about trying MetapixeGUI for yourself this list will help you know what is being installed on your OS X computer:

/sw/lib/libjpeg.62.0.0.dylib
/sw/lib/libjpeg.62.dylib
/sw/lib/libpng.3.1.2.7.dylib
/sw/lib/libpng.3.dylib

and also

/Applications/MetapixelGUI/MetapixelGUI.app
/Applications/MetapixelGUI/Readme.rtf
/Applications/MetapixelGUI/License.rtf