Thursday, September 29, 2011

How to Make Photos of Documents Look Like Scanned Copies

If you have a digital camera you already have a basic scanner, except photographs from your camera just doesn’t look like a scanned copy. The problem with using a camera as a scanner is perspective.

Perspective is a great thing when you know how to use it to your advantage. Photographers and digital artists love to toy with perspective to produce astonishing optical illusions like tilt-shift and 3D. But when scanning documents, perspective is the ultimate spoilsport. Perspective makes photos of documents look skewed - get too close to the document, and the camera will produce a fish-eye like effect; get too far, and the photo will appear dark because the light from your camera flash cannot illuminate the scene/document enough.

Unless you have a fully equipped studio at home, you can never completely eliminate the problems of uneven lighting and the unavoidable phenomenon of perspective.

So how do you solve this problem? Digital post-processing, of course. But I’m not going to drag you through pages after pages of Photoshop tutorial. Instead, what I have with me is an automated program called Cam to Scan.

Cam to Scan Lite is an image processing application designed for optimizing photographed documents and make them look more like scanned documents. The program can automatically detect the outline of a document, straighten the image and adjust color and brightness to improve the readability.

cam2scan

Fire up this program and load an image of the document. Cam to Scan will automatically try to find the outline of the page. If that fails, you can manually set the outline by clicking on the four corners of the page with the mouse.

Once the outline is set, click on the Straighten button to kill the effects of perspective. This function straightens an object to its original rectangular shape. The object may additionally be rotated and mirrored if necessary.

Finally click on the Brightness button to automatically adjust color, brightness and contrast of the image. The final edited image closely resembles the output of a flatbed scanner.

after-1

The discoloration you see in the image is the natural color of the page (it is an old book). For better results, take photos under natural light. The one below was taken under sunlight without Flash and by manually tweaking the white balance in the camera. The image is after processing by Cam to Scan.

100

I’m using the free Lite version of Cam to Scan which has many limitations such as you cannot save an image as PNG, and cannot manually adjust brightness and color. It also doesn’t do batch jobs. The paid version has these restrictions lifted.

You might be able to get similar, if not better, results from an image editing software such as Photoshop. But as an automated tool, Cam to Scan does a pretty wonder job and at a fraction of the time you would have to spend on Photoshop. Not to mention, you would have to know how to use it.

0 comments:

Post a Comment