L_LocalHistoEqualizeBitmap

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#include "l_bitmap.h"

L_LTIMGCLR_API L_INT L_LocalHistoEqualizeBitmap(pBitmap, nWidth, nHeight, nxExt,nyExt, uType, uSmooth, uFlags)

pBITMAPHANDLE pBitmap;	/* pointer to the bitmap handle */
L_INT nWidth;	/* width of the local histogram equalizer rectangle */
L_INT nHeight;	/* height of the local histogram equalizer rectangle */
L_INT nxExt;	/* width extention */
L_INT nyExt;	/* height extention */
L_UINT uType;	/* color space */
L_UINT uSmooth;	/* smoothing size */
L_UINT32 uFlags;	/* flags*/

Linearizes the number of pixels locally in a bitmap, based on the specified color space. This can be used to bring out the detail in dark areas of an image, and smooth the edges between blocks.

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.

Parameter	Description
pBitmap	Pointer to the bitmap handle referencing the bitmap to be changed.
nWidth	The width of the local histogram equalizer rectangle in pixels. The width should be more than zero.
nHeight	The height of the local histogram equalizer rectangle in pixels. The height should be more than zero.
nxExt	The extension of the width of the local histogram equalizer rectangle, in pixels.
nyExt	The extension of the height of the local histogram equalizer rectangle, in pixels.
uType	Flag that indicates which color space to equalize. Possible values are:
	Value	Meaning
	RGB_SPACE	[0x0001] Linearizes the number of pixels across the RGB color space.(separated channels)
	YUV_SPACE	[0x0002] Linearizes the number of pixels across the YUV color space.(Best results)
	GRAY_SPACE	[0x0004] Linearizes the number of pixels per gray level in a gray level representation of the image.
uSmooth	Size of the area to be used when smoothing the edges between localized blocks. Possible values range from 0 to 7, but if nHeight is less than or equal to 7 then the maximum value for this item is nHeight - 1. If uSmooth = 0 the function will operate without smoothing edges.
uFlags	Reserved for future use. Must be 0.

Required DLLs and Libraries

LTIMGCLR

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.

See Also

Functions:	L_ChangeBitmapIntensity, L_GammaCorrectBitmap, L_ChangeBitmapContrast, L_HistoContrastBitmap, L_StretchBitmapIntensity, L_RemapBitmapIntensity, L_InvertBitmap, L_ChangeBitmapHue, L_ChangeBitmapSaturation, L_FillBitmap, L_GetPixelColor, L_PutPixelColor, L_GetBitmapHistogram, L_WindowLevel, L_AutoColorLevelBitmap, L_ColorLevelBitmap, L_CorrelationBitmap, L_GrayScaleToDuotone, L_GrayScaleToMultitone, L_HolesRemovalBitmapRgn, L_SelectiveColorBitmap, L_SkeletonBitmap, L_DlgLocalHistoEqualize
Topics:	Raster Image Functions: Modifying Intensity Values
	Changing Brightness and Contrast
	Raster Image Functions: Changing Brightness and Contrast

Example

For complete sample code, refer to the CHILD.C module of the DEMO example. This example loads a bitmap and applies local histogram equalization.

#define MAKE_IMAGE_PATH(pFileName) TEXT("C:\\Users\\Public\\Documents\\LEADTOOLS Images\\")pFileName


#if defined (LEADTOOLS_V16_OR_LATER)
 L_INT LocalHistoEqualizeBitmapExample(L_VOID)
{
   L_INT nRet;
   /* Bitmap handle to hold the loaded image. */
   BITMAPHANDLE LeadBitmap;

   /* 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;

   /* Local Histogram equalize the bitmap */
   nRet = L_LocalHistoEqualizeBitmap(&LeadBitmap, 15,15,100,100, YUV_SPACE,2 , 0);
   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;
}
#else
 L_INT LocalHistoEqualizeBitmapExample(L_VOID)
{
   L_INT nRet;
   /* Bitmap handle to hold the loaded image. */
   BITMAPHANDLE LeadBitmap;

   /* 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;

   /* Local Histogram equalize the bitmap */
   nRet = L_LocalHistoEqualizeBitmap(&LeadBitmap, 15,15,100,100, YUV_SPACE,2 );
   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;
}
#endif // LEADTOOLS_V16_OR_LATER