#include "l_bitmap.h"
L_LTIMGCOR_API L_INT EXT_FUNCTION L_AutoBinarizeBitmap(pBitmap, uFactor, uFlags)
pBITMAPHANDLE pBitmap; |
pointer to the bitmap handle |
L_UINT uFactor; |
threshold factor |
L_UINT uFlags; |
flags |
Applies binary segmentation to a bitmap automatically.
This feature is available in version 16 or higher.
Parameter | Description | |
pBitmap | Pointer to the bitmap handle referencing the bitmap having binary segmentation applied automatically. | |
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] Do not 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. |
SUCCESS |
The function was successful. |
< 1 |
An error occurred. Refer to Return Codes. |
AutoBinarize converts a colored image into a image automatically, without losing important image features such as text. This function uses several pre-processing and threshold operations which enable the user to extract the key features of any colored image. It can be adjusted to be suitable for a specific input device, such as a scanner or camera. It is ideal for making unclear document images more readable. This function is especially useful for improving recognition results (OCR, Barcode, OMR, ICR).
L_AutoBinarizeBitmap options:
Automatic pre-processing
Pre-processing using background elimination
Pre-processing using color leveling
Perform automatic, percentile or median threshold
Manually specify a threshold value
To update a status bar or detect a user interrupt during execution of this function, refer to L_SetStatusCallback.
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
For a listing of the exact DLLs and Libraries needed, based on the toolkit version, refer to Files To Be Included With Your Application. |
Win32, x64, Linux.
#define MAKE_IMAGE_PATH(pFileName) TEXT("C:\\Users\\Public\\Documents\\LEADTOOLS Images\\")pFileName
L_INT AutoBinarizeBitmapExample(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("cannon.jpg")), &LeadBitmap, sizeof(BITMAPHANDLE), 0, ORDER_BGR, NULL, NULL);
if(nRet !=SUCCESS)
return nRet;
nRet = L_AutoBinarizeBitmap(&LeadBitmap, 0, AUTO_BINARIZE_PRE_AUTO | AUTO_BINARIZE_THRESHOLD_AUTO);
if(nRet !=SUCCESS)
return nRet;
nRet = L_SaveBitmap(MAKE_IMAGE_PATH(TEXT("Result.BMP")), &LeadBitmap, FILE_BMP, 24, 0, NULL);
if(nRet !=SUCCESS)
return nRet;
//free bitmap
if(LeadBitmap.Flags.Allocated)
L_FreeBitmap(&LeadBitmap);
return SUCCESS;
}
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