Doodle Scan

While scanning my time travel zine I thought it would be nice to include some drawings I've done as part of my website, similar to how Ana has on her site. Whenever I've tried in the past, removing a background to standard that is good enough to put on another colour background is near impossible without spending a long time in Pixelmator fixing all the edge artifacts. I came across a couple of websites that do this and I noticed that they do it all in-browser so I started digging around — they convert the uploaded image to a bitmap with createImageBitmap and then going over every pixel and it's rgba values to determine if it should be kept, or made transparent. It was time to do some maths which I am famously not good at - most of what is below is my best estimate at explaining how this works. tl;dr: The website is up at doodlescan.rknight.me — read on for the technical nonsense. Also Jeff is back. Removing the Background "Relative luminance" is the key to this part as defined by…