Mona Lisa Tile

After tiling for the first time I was left with an assortment of odd shaped cut off pieces. I decided to make some art.

Not having much artistic talent myself I though it might be nice to work with someone else’s art.

Digitizing the Tiles

I started out by labeling each tile and taking a picture of them in groups. I used the checkerboard to find the homography for the floor plane. This allowed me to re-project the images of the tiles onto a flat plane and remove the distortion caused by the camera’s perspective. OpenCV makes this all pretty easy.

Next I applied some thresholding, simple filtering, and contour extraction to get an individual image mask of each tile.

Tiling an Image

I sequentially read in each tile and place them over an image. I started out just placing each tile at the brightest location it could fit. This was accomplished by finding the max of a cross correlation of the tile profile run across the image.

This worked pretty well for Rothkos…

But a little worse for Mona Lisa…

The most apparent problem is that as we simply fill in the brightest sections of the image we loose any sense of proportional brightness. You can see below that for a simple gradient we just progressively fill from top to bottom.

To fix this we can blur each tile and subtract the created mosaic from the original image. This results in the program discouraging additional tiles in already filled areas and allows us to have gradations of luminance. You can see below that the simple gradient image now produces sections of varying tile density.

Now that we can produce gradients in value it’s time to start copying some art. Note that squinting helps a bit (pro art tip).

Mona Lisa, Leonardo da Vinci and Girl with a Pearl Earring, Johannes Vermeer

The Birth of Venus, Sandro Botticelli and Self Portrait, Dedicated to Dr Eloesser, Frida Kahlo

Creating the Work

When I originally took the pictures of the tiles I numbered each one. This allowed me relocate each physical tile and map it onto the image. I added grid lines for inches and feet so that I could more accurately place each piece.

Next I added a grid to some cement board and started placing tiles. To add some contrast and fill in the dead space I added a black grout background.

The image stands about 7 feet tall. Besides the grout it is made of 100% recycled products.

Thanks for reading!