LBitmap::AutoBinarize

#include "ltwrappr.h"

L_INT LBitmap::AutoBinarize(uFactor, uFlags)

L_UINT uFactor;

/* threshold factor */

L_UINT uFlags;

/* flags*/

Applies binary segmentation to a bitmap automatically. This function is useful for improving recognition results (OCR, Barcode, OMR, ICR). This feature is available in version 16 or higher.

Parameter

Description

uFactor

Threshold Factor. The meaning of this factor depends on which type of thresholding is being used. For more information see the description of the uFlags parameter.

uFlags

Flags that indicate the type of pre-processing to perform on the bitmap and the type of thresholding to use. You can use a bitwise OR (|) to specify one flag from each group.

 

The following flags indicate the type of pre-processing to perform on the bitmap:

 

Value

Meaning

 

AUTO_BINARIZE_PRE_AUTO

[0x00000000] Perform automatic pre-processing. This is the default value.

 

AUTO_BINARIZE_NO_PRE

[0x00000001] Dont perform pre-processing.

 

AUTO_BINARIZE_PRE_BG_ELIMINATION

[0x00000002] Eliminate the background of the bitmap but keep the key features, such as text.

 

AUTO_BINARIZE_PRE_LEVELING

[0x00000004] Perform automatic color leveling.

 

The following flags indicate type of threshold to use:

 

Value

Meaning

 

AUTO_BINARIZE_THRESHOLD_AUTO

[0x00000000] Perform automatic thresholding. This is the default value.

 

AUTO_BINARIZE_THRESHOLD_USER

[0x00000010] Let the user choose the threshold value, to be passed in uFactor. Valid values range from 0 to 255.

 

AUTO_BINARIZE_THRESHOLD_PERCENTILE

[0x00000020] Perform percentile thresholding. In this case uFactor is the percentage of black pixels at which to perform thresholding, expressed in hundredths of a percent. For example, 500 means 5 percent. Valid values range from 0 to 10000

 

AUTO_BINARIZE_THRESHOLD_MEDIAN

[0x00000040] Perform median thresholding.

Returns

SUCCESS

The function was successful.

< 1

An error occurred. Refer to Return Codes.

Comments

This function is useful for improving recognition results (OCR, Barcode, OMR, ICR).

LBitmap::AutoBinarize options:

To update a status bar or detect a user interrupt during execution of this function, refer to LBase::EnableStatusCallback.

This function does not support 12 and 16-bit grayscale and 48 and 64-bit color images. If the image is 12 and 16-bit grayscale and 48 and 64-bit color, the function will not return an error.

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

LTDIS
LTFIL
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.

See Also

Functions:

LBitmap::Despeckle, LBitmap::Deskew, LBitmap::DeskewExt, LBitmap::IntensityDetect, LBitmap::LineRemove, LBitmap::BlankPageDetector, LBitmap::AutoBinary, LBitmap::HolePunchRemove, LBitmapRgn::HolesRemovalRgn, LBitmap::BorderRemove, LBitmap::InvertedText, LBitmap::DotRemove, LBitmapBase::ColorRes, LBitmap::ColorLevel, LBitmap::DynamicBinary, LBitmap::Smooth, LBitmap::Invert, Class Members

Topics:

Raster Image Functions: Modifying Intensity Values

 

Changing Brightness and Contrast

 

Raster Image Functions: Detecting and Enhancing Edges and Lines

 

Removing Noise

 

Cleaning Up 1-Bit Images

 

Raster Image Functions: Cleaning Up 1-Bit Images

 

Raster Image Functions: Doing Color Expansion or Reduction

Example

#define MAKE_IMAGE_PATH(pFileName) TEXT("C:\\Users\\Public\\Documents\\LEADTOOLS Images\\")pFileName
L_INT LBitmap__AutoBinarizeExample()
{
   L_INT nRet;
   LBitmap LeadBitmap;
   
   nRet = LeadBitmap.Load(MAKE_IMAGE_PATH(TEXT("cannon.jpg")), 0,ORDER_BGR);
   if(nRet !=SUCCESS)
      return nRet;
   
#if defined (LEADTOOLS_V16_OR_LATER)
   nRet = LeadBitmap.AutoBinarize (0, AUTO_BINARIZE_PRE_AUTO | AUTO_BINARIZE_THRESHOLD_AUTO);
   if(nRet !=SUCCESS)
      return nRet;
#endif
   return SUCCESS;
}