Yesterday, we released an update to PhotoScan, an app for iOS and Android that allows you to digitize photo prints with just a smartphone. One of the key features of PhotoScan is the ability to remove glare from prints, which are often glossy and reflective, as are the plastic album pages or glass-covered picture frames that host them. To create this feature, we developed a unique blend of computer vision and image processing techniques that can carefully align and combine several slightly different pictures of a print to separate the glare from the image underneath.
When taking a single picture of a photo, determining which regions of the picture are the actual photo and which regions are glare is challenging to do automatically. Moreover, the glare may often saturate regions in the picture, rendering it impossible to see or recover the parts of the photo underneath it. But if we take several pictures of the photo while moving the camera, the position of the glare tends to change, covering different regions of the photo. In most cases we found that every pixel of the photo is likely not to be covered by glare in at least one of the pictures. While no single view may be glare-free, we can combine multiple pictures of the printed photo taken at different angles to remove the glare. The challenge is that the images need to be aligned very accurately in order to combine them properly, and this processing needs to run very quickly on the phone to provide a near instant experience.
We #celebratephotography here at Adafruit every Saturday. From photographers of all levels to projects you have made or those that inspire you to make, we’re on it! Got a tip? Well, send it in!