LEADTOOLS Raster Imaging C DLL Help > Function References > L_BlankPageDetectorBitmap |
#include "l_bitmap.h"
L_LTIMGCOR_API L_INT EXT_FUNCTION L_BlankPageDetectorBitmap(pBitmap, bIsBlank, pAccuracy, pMargins, uFlags)
pBITMAPHANDLE pBitmap; |
/* pointer to the bitmap handle */ |
L_BOOL * bIsBlank; |
/* address of the variable to be updated */ |
L_UINT * pAccuracy; |
/* address of the variable to be updated */ |
pPAGEMARGINS pMargins; |
/* pointer to a structure of page margin */ |
L_UINT uFlags; |
/* flags */ |
Determines whether the scanned image is a blank page or not.
Parameter |
Description |
|
pBitmap |
Pointer to the bitmap handle that references the image to be tested. |
|
bIsBlank |
Address of the variable to be updated with image status indicating whether it is a blank page or not. Possible values are: |
|
|
Value |
Meaning |
|
True |
Blank page. |
|
False |
Non-blank page. |
pAccuracy |
Address of the variable to be updated with the accuracy percentage of the result. Possible values range from 0 to 10000. This value is divided internally by the value 100. |
|
pMargins |
Pointer to the PAGEMARGINS structure that contains information about excluded margins. Pass NULL as no margins to exclude. |
|
uFlags |
Flags that indicate how to consider blank pages and the function behavior. You can combine values when appropriate by using a bitwise OR ( | ). Possible values are: |
|
|
Consider noisy page as a blank page: |
|
|
Value |
Meaning |
|
BLANK_DETECT_EMPTY |
[0x00000000] A page must be totally blank. |
|
BLANK_DETECT_NOISY |
[0x00000001] A page may have some noise. This is the default value. |
|
Consider page which bleeds through its other side as a blank page: |
|
|
Value |
Meaning |
|
BLANK_NOT_BLEED_THROUGH |
[0x00000000] Don't ignore bleed through from the page. |
|
BLANK_BLEED_THROUGH |
[0x00000010] Ignore bleed through from the page. This is the default value. |
|
Consider lined page as a blank page: |
|
|
Value |
Meaning |
|
BLANK_DONT_DETECT_LINES |
[0x00000000] Don't consider lined page as a blank page. This is the default value. |
|
BLANK_DETECT_LINES |
[0x00000100] Consider lined page as a blank page. |
|
Indicate whether to ignore blank spaces around the page edges: |
|
|
Value |
Meaning |
|
BLANK_DONT_USE_ACTIVE_AREA |
[0x00000000] Don't ignore blank spaces around the page edges. This is the default value. |
|
BLANK_USE_ACTIVE_AREA |
[0x00001000] Ignore blank spaces around the page edges. |
|
Indicate whether to use default margins or user-specified margins: |
|
|
Value |
Meaning |
|
BLANK_DEFAULT_MARGIN |
[0x00000000] Use default margins, which are computed automatically by the function based on the page dimensions. This is the default value. |
|
BLANK_USER_MARGIN |
[0x00010000] Use the user-specified margins, which are specified in pMargins. |
Returns
SUCCESS |
The function was successful. |
< 1 |
An error occurred. Refer to Return Codes. |
Comments
Scanned images can contain blank (empty) pages. This function determines whether the scanned image is a blank page or not, detects noisy, bleed through, and lined blank pages with high precision and speed, and provides a percentage accuracy of the result. This function helps reduce disk storage space required for scanned images.
This function does not support signed data images. It returns the error code ERROR_SIGNED_DATA_NOT_SUPPORTED if a signed data image is passed to this function.
This function does not support 32-bit grayscale images. It returns the error code ERROR_GRAY32_UNSUPPORTED if a 32-bit grayscale image is passed to this function.
Required DLLs and Libraries
LTIMGCOR |
Platforms
Win32, x64, Linux.
See Also
Example
#define MAKE_IMAGE_PATH(pFileName) TEXT("C:\\Users\\Public\\Documents\\LEADTOOLS Images\\")pFileName L_LTIMGCOR_API L_INT BlankPageDetectorBitmapExample(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; nRet = L_BlankPageDetectorBitmap (&LeadBitmap, &IsBlank, &Accuracy, NULL, BLANK_DETECT_NOISY|BLANK_BLEED_THROUGH|BLANK_DEFAULT_MARGIN); if(nRet !=SUCCESS) return nRet; //free bitmap if(LeadBitmap.Flags.Allocated) L_FreeBitmap(&LeadBitmap); return SUCCESS; }