L_BlankPageDetectorBitmapExt

#include "l_bitmap.h"

L_LTIMGCOR_API L_INT EXT_FUNCTION L_BlankPageDetectorBitmapExt(pBitmap, bIsBlank, pAccuracy, PMargins, uSensitivity, uFlags)

Determines whether the scanned image is a blank page.

Parameters

pBITMAPHANDLE pBitmap

Pointer to the bitmap handle that references the image to be tested.

L_BOOL * bIsBlank

Pointer to a flag to be updated with a value indicating whether the image is a blank page. Possible values are:

L_UINT * pAccuracy

Pointer to a variable to be updated with the accuracy of the result, in hundredths of a percent. Possible values range from 0 to 10000. This value is divided internally by 100.

pPAGEMARGINS PMargins

Pointer to the PAGEMARGINS structure that contains information about excluded margins. Pass NULL if there are no margins to exclude.

L_UINT uSensitivity

Determines the sensitivity of the blank page detection, based on the amount of black pixels in the image. Possible values range from 0 to 100.

L_UINT uFlags

Flags that indicate how to define blank pages and determine the function's behavior. Values can be combined when appropriate by using a bitwise OR (|). Use a flag only if it describes the needed behavior. In many cases the default behavior is fine, and no flag is needed.

Note: Some uFlags values are being deprecated in Version 20. They will be removed from the toolkits, effective with LEADTOOLS version 21.

Indicates whether a blank page can have noise. A page is noisy if the height of the noisy object in the image is greater than 10 pixels, although this can be changed. Possible values are:

Indicates whether a blank page can have bleed-through from its other side. Possible values are:

Indicates whether a blank page can have lines. Possible values are:

Indicates whether to include blank spaces around the page's edges. Possible values are:

Indicates whether to use the default or user-specified margins. Possible values are:

Indicates which unit of measure to use. Possible values are:

Indicates whether to use text analysis. Possible values are:

Returns

Comments

For various reasons, documents being scanned can contain a significant number of blank pages. Disk storage space for the scanned items can be reduced if such pages can be removed before the documents are stored.

This function determines whether the scanned image is a blank page. It can detect noisy, bleed-through, and lined blank pages with high precision and speed, and provides an accuracy percentage for the result.

Support for this function is available in the Document and Medical Imaging toolkits.

This function does not support signed data images. It returns the ERROR_SIGNED_DATA_NOT_SUPPORTED error code if a signed data image is passed to this function.

This function does not support 32-bit grayscale images. It returns the ERROR_GRAY32_UNSUPPORTED error code if a 32-bit grayscale image is passed to this function.

This function does not support 12-, 16-, 48-, or 64-bit images. It returns the ERROR_INV_PARAMETER error code if such an image is passed to this function.

Deprecated uFlags Members

The following flags are being deprecated in Version 20. They will be removed from the toolkits, effective with LEADTOOLS version 21.

• BLANK_DETECT_EMPTY
• BLANK_NOT_BLEED_THROUGH
• BLANK_DONT_DETECT_LINES
• BLANK_DONT_USE_ACTIVE_AREA
• BLANK_DEFAULT_MARGIN

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.

L_INT BlankPageDetectorBitmapExtExample(L_VOID) 
{ 
   L_INT nRet; 
   BITMAPHANDLE LeadBitmap;   /* Bitmap handle hold the loaded image. */ 
 
                              /* Load the bitmap, keeping the bits per pixel of the file */ 
   nRet = L_LoadBitmap(MAKE_IMAGE_PATH(TEXT("IMAGE1.CMP")), &LeadBitmap, sizeof(BITMAPHANDLE), 0, ORDER_BGR, NULL, NULL); 
   if (nRet != SUCCESS) 
      return nRet; 
 
   /* Check if the image is a blank page the bitmap */ 
   L_BOOL IsBlank = 1; 
   L_UINT Accuracy = 0; 
   L_UINT Sensitivity = 80; 
 
   nRet = L_BlankPageDetectorBitmapExt(&LeadBitmap, 
      &IsBlank, 
      &Accuracy, 
      NULL, 
      Sensitivity, 
      BLANK_DETECT_NOISY | BLANK_BLEED_THROUGH); 
 
   if (IsBlank) 
      OutputDebugString(L_TEXT("Image is blank.\n")); 
   else 
      OutputDebugString(L_TEXT("Image is not blank.\n")); 
 
   //free bitmap  
   L_FreeBitmap(&LeadBitmap); 
 
   return nRet; 
}