1. A method of extracting note content using a computer system having one or more processors and memories, comprising: receiving image data containing a visual representation of a scene having a plurality of notes, each of the plurality of notes having a color; generating, by the one or more processors, a plurality of indicators, each indicator indicative of a color class of a respective pixel or group of pixels in the image data and based on color values of the pixel or group of pixels; based on the plurality of indicators, determining, by the one or more processors, a general boundary within the image data of one of the plurality of notes; and extracting, by the one or more processors and from the image data, content of the one of the plurality of notes using the general boundary.