As I mentioned in my previous post, Correct Photos of Documents – Ambient Lighting, most images of documents suffer from skew. There are two types of skew: two-dimensional and three-dimensional.

Text is typically parallel to the top and bottom of the paper. Simply put, two-dimensional skew is the angle of the text when compared to the top or bottom edge of the image. This type of skewing can occur in photos of documents as well as document images produced by a scanner. While it is relatively easy to correct with a simple rotate, determining the angle of rotation can be tricky. Fortunately, LEADTOOLS includes a DeskewCommand class that can determine the angle of skew.

One of the most foundational features in document imaging is image cleanup (also called preprocessing). When paper documents are scanned to digital form there are almost always imperfections. The paper can be at an angle, hole punches leave large black dots, folded paper introduces lines, and at the very least dust speckles litter small, dark dots throughout the image. All of these can have an adverse trickle-down effect on many other algorithms such as OCR, Forms, Barcode, Compression and more.

There is one caveat with most document imaging libraries: the document images must be black and white. While technically true for LEADTOOLS as well, it's not a limitation whatsoever. Each of the LEADTOOLS document cleanup functions return information on what it has done. For example, you can get the deskew angle, rectangle to crop, or region to fill and then apply those same operations on a color image:

Forms recognition is a common requirement for document imaging projects. Therefore it is no surprise that there are many companies and services that provide a solution for it. With that in mind, what sets LEADTOOLS apart? Forms alignment is one of the key features that catapults LEADTOOLS Forms Recognition above other products because it offers the best accuracy across the widest gamut of devices and documents.

We have had a number of customers approach us with documents that, to the human eye, appeared to be clean and properly scanned. However, the results still failed to return accurate results. In some cases, the exact same piece of paper would produce offbeat results when using different scanners. In the following white paper we will explain several alignment problems which LEADTOOLS can automatically correct and produce better accuracy than the competition. Click the link below to read this new white paper: