I am looking for a way to compare two images to see how similar they are. Googling it produces tons of image processing results (cropping, re-sizing, etc.), but nothing that would do approximate comparisons of images. There is one Node.js library, but it is version 0.0.1 and relies on various 3rd party system packages, so not stable or portable.
Something along these lines:
var imgComparator = require('some-awesome-image-comparator-module');
// result would be between 1.0 and 0.0, where 1.0 would mean exact match
var result = imgComparator.compare('/path/to/image/1.png', '/path/to/image/2.png');
There is node-opencv module, you might use it in order to perform heavy operation like image comparison. Good topic on that is here: Simple and fast method to compare images for similarity