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L_PerspectiveDeskew

Summary

Detects and automatically deskews a 3D document image.

Syntax

#include "Ltimgcor.h"

L_LTIMGCOR_API L_INT L_PerspectiveDeskew(pBitmap)

Parameters

pBITMAPHANDLE pBitmap

Pointer to the bitmap handle referencing the bitmap to be deskewed.

Returns

Value	Meaning
SUCCESS	The function was successful.
< 1	An error occurred. Refer to Return Codes.

Comments

This function can change the specified image. To keep the original image unchanged, use this function on a copy.

For the best results, the document's boundaries should be inside the captured view and have a different background color than the background of the captured view.

Use the L_PerspectiveDeskew function if there is depth (z-axis) deformation as well as deformation along the x- and y- axes. Use the L_DeskewBitmap function to fix 2D orientation.

Unlike the L_DeskewBitmap function, the L_PerspectiveDeskew does not look at the content of the captured document.

If the L_PerspectiveDeskew fails to correct the skew, the original image is not changed.

To detect and deskew the 3D document image with specifying options, call L_PerspectiveDeskewExt.

This function can only process entire images. It does not support regions.

This function supports 24 and 32-bit color images.

Perspective Deskew Function - Before

Perspective Deskew Function - After

View additional platform support for this Perspective Deskew function.

Required DLLs and Libraries

LTIMGCOR
For a listing of the exact DLLs and Libraries needed, based on the toolkit version, refer to Files To Be Included With Your Application.

Platforms

Win32, x64, Linux.

Example

This example loads a bitmap and applies perspective deskew filter.

L_INT PerspectiveDeskewFilterBitmapExample(L_VOID) 
{ 
   L_INT nRet; 
   BITMAPHANDLE LeadBitmap;   /* Bitmap handle to hold the loaded image. */ 
 
   /* Load the bitmap, keeping the bits per pixel of the file */ 
   nRet = L_LoadBitmap(MAKE_IMAGE_PATH(TEXT("PerspectiveDeskew.jpg")), &LeadBitmap, sizeof(BITMAPHANDLE), 0, ORDER_BGR, NULL, NULL); 
   if (nRet != SUCCESS) 
      return nRet; 
 
   /* Apply a perspective deskew filter*/ 
   nRet = L_PerspectiveDeskew(&LeadBitmap); 
   if (nRet != SUCCESS) 
   { 
      //free bitmap 
      if (LeadBitmap.Flags.Allocated) 
         L_FreeBitmap(&LeadBitmap); 
 
      return nRet; 
   } 
 
   nRet = L_SaveBitmap(MAKE_IMAGE_PATH(TEXT("Result.BMP")), &LeadBitmap, FILE_BMP, 24, 0, NULL); 
 
   //free bitmap 
   if (LeadBitmap.Flags.Allocated) 
      L_FreeBitmap(&LeadBitmap); 
 
   return nRet; 
}