The manual noise removal will take up the most amount of time.
To convert an image in your Dropbox account to a scan: If desired, make adjustments to the save settings. If desired, make edits or scan additional pages. Either take a picture of the content you’d like to scan, or select an existing image on your mobile device. Convert an image in your Dropbox account to a scan To scan a new file to your Dropbox account: Open the Dropbox app on your mobile device.
Not using Dropbox yet? Learn all about the doc scanner.