This photograph by Běla Kolářová caught my attention as I walked past it in the museum. It's a photograph of her hair. I love its subtlety and ambiguity, and while I wasn't sure straight away I wanted to use it, I kept coming back to it.
In terms of the tech, the path-to-melody algorithm is a variation on the traced-to-melody algorithm. Where the traced-to-melody algorithm traverses an image from left to right (and only left-to-right), creating a melody for each different-colored path, the path-to-melody algorithm is able follow a path in any direction.
For a path - where a path is a continuous line of the same color - the left-most point is found, and is used as the starting point. The path is then followed, up/down/left/right (with diagonals) through the image. For each pixel in the path a note is added to the melody, the pitch of which is determined by the pixel's height within the image.
Here is an example of how we can draw some paths through the artwork, each of these paths is converted into its own melody:
This track went through quite a few different iterations before I found the sounds and feel that I wanted. It was a fairly frustrating process but I'm really happy with the result. Here's an excerpt of the track: