Enhance camera "scanned" documents with gm

enhancescan.js

var gm = require('gm');

if (process.argv.length != 4) {
    console.log('Usage: enhancescan input output');
    process.exit(2);
}

var input = process.argv[2];
var output = process.argv[3];

gm(input)
    .type('Grayscale')
    .level(40, 1, 120)
    .write(output, function (err) {
        if (err) { return console.log(err); }

        console.log('Enhanced scan written to', output);
    });