Data capture, character recognition OCR ICR OMR CHR BCR, image processing, forms data capture, document indexing, automatic data extraction Data capture, character recognition OCR ICR OMR CHR BCR, image processing, forms data capture, document indexing, automatic data extraction
Recogniform Deskew SDK

Recogniform Deskew SDK

This deskew sdk (API) allows the automatic skew detection and correction in scanned or faxed images. The skew is the inevitable slope present in the images acquired by scanners using an ADF (automatic document feeder) or received by fax. Straightening the images is a very important pre-processing step for improving the compression rate, the visualization aspect, the line-removal and the accuracy using ICR/OCR.

While other libraries usually allow users to deskew only monochrome images, Recogniform library allows you to deskew both gray-scale and color images!

Using interpolation in skew correction, the aliasing due to the rotation is minimized and really perfect images are obtained (as rotating the paper!).

Before applying the DESKEW library
After applying the DESKEW library
You can perform the deskew (skew detection and correction) in one-step, or in two distinct steps.

You can set the following parameters:
  • Max Angle
    system will try to detect and correct skew only from -MaxAngle to +MaxAngle.
  • Resolution
    the smallest skew to detect. It is Usually 0.1°, but if you need fast processing you can increase this value.
  • Speed and accuracy
    the value for balancing speed/accuracy ratio.
  • Background Color
    the color of the new background after the rotation
  • Interpolation
    this option performs interpolation to obtain a better result and to avoid aliasing
You have to supply the DIB (Device Independent Bitmap) in input to the process.

The deskew procedure is fast and accurate.

For testing this library you can download a demo application (400 KB) that allows you to use this function with your TIF images: please give us your feedback and your comments after the test !

Here is source code in Microsoft Visual C++ of a sample application using the deskew library:

#include "stdafx.h"
#include "stdio.h"
#include "recodeskew.c"

int APIENTRY WinMain(HINSTANCE hInstance,
                     HINSTANCE hPrevInstance,
                     LPSTR     lpCmdLine,
                     int       nCmdShow)

 // Load dynamically the library

 // Init the DESKEW session
 int Session= DESKEW_Init("demo", "demo");

 long hBitmap;

 // Check if a DIB is available in clipboard
 bool bAvail= IsClipboardFormatAvailable(CF_DIB);

 hBitmap = 0;

 if (bAvail)
   // Open the Clipboard
   // Retrieve the DIB from clipboard 
   hBitmap = (long) GetClipboardData(CF_DIB);

   // Detect and correct skew on the DIB
   double SkewAngle= DESKEW_DetectAndCorrect(Session, (long) hBitmap);


   // Set the deskewed DIB to clipboard
   SetClipboardData(CF_DIB, (void*)hBitmap);

   // Close the Clipboard	

   char  buffer[200];

   // Format the output message
   if (SkewAngle!=0)

    sprintf( buffer, "Image deskewed by %f degree !
      You can paste in your application...", SkewAngle);


    sprintf( buffer, "Image don't need to be deskewd !");

   // Show the result
  MessageBox(NULL, buffer, "RESULT", MB_OK);
 // Show an error message
 else MessageBox(NULL, "Unable to paste DIB", "ERROR", MB_OK);

 // Close the session

 // Unload the library	

 return 0;
Evaluation version
Through the download section you can download an evaluation version of this product.

Looking a solution ready to use capable of processing any type of documents and forms, printed or handwritten, structured (fixed layout) or unstructured (variable layout)? Choose Recogniform Reader!
To more information about Recogniform Deskew SDK and our solution for data capture and image processing, you can send us a email to or fill the below form.

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  • Recogniform Deskew SDK - Purchase

    Deskew SDK - Royalties Free

    The Deskew SDK is royaltes-free which you can deploy and use the software that integrates the capabilities up to 1000 computers without additional cost. Using this SDK require the license agreement subscription whereby order evasion does not require physical shipment. If you want to deploy over 1000 runtime licenses you need to purchase multiple licenses of the product.
    € 599,00 + VAT