L_CLAHE

#include "l_bitmap.h"

L_LTIMGCOR_API L_INT L_CLAHE(pBitmap0, Alpha, TileSize, nfclipLimit, nBinNumbe, uFlags)

pBITMAPHANDLE pBitmap0;	pointer to the bitmap handle
L_FLOAT Alpha;	distribution parameter value
L_UINT TileSize;	Size of tiles
L_FLOAT nfclipLimit;	contrast enhancement limit
L_UINT nBinNumbe;	Number of bins for the histogram
L_UINT uFlags;	flags

Adjusts the image contrast using the Contrast Limited Adaptive Histogram Equalizer (CLAHE) method, Which uses several histograms each corresponding to a distinct section in the image while limiting the amplification of the noise in the image.

Parameter	Description
pBitmap0	Pointer to the bitmap handle that references the bitmap to be affected.
Alpha	Non-negative real scalar specifying a distribution parameter.
TileSize	Positive integer specifying the size of tiles ranging from 1 to 60.
nfclipLimit	Real scalar in the range [0, 1] that specifies a contrast enhancement limit. Higher numbers result in more contrast.
nBinNumbe	Multiple of 2 integer in the range [2, 1024] that specifies the number of bins for the histogram used in building a contrast enhancing transformation.
uFlags	Flags specifying the desired histogram shape for the image tiles. Possible values are: CLAHE_RAYLIEH CLAHE_EXPONENTIAL CLAHE_NORMAL CLAHE_SIGMOID CLAHE_RETURN8BITIMAGE CLAHE_RETURN16BITIMAGE

Returns

SUCCESS	The function was successful.
<1	An error occurred. Refer to Return Codes.

Comments

This function supports 8 and 16-bit grayscale images.

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.

Example

#define MAKE_IMAGE_PATH(pFileName) TEXT("C:\\Users\\Public\\Documents\\LEADTOOLS Images\\")pFileName 
L_INT CLAHEBitmapExample(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("IMAGE3.dcm")), &LeadBitmap, sizeof(BITMAPHANDLE), 0, ORDER_BGR, NULL, NULL); 
   if(nRet !=SUCCESS) 
      return nRet ; 
   /* Apply a CLAHE filter */ 
   nRet = L_CLAHE(&LeadBitmap, 0.5f, 9, 0.04f, 512, CLAHE_RAYLIEH); 
   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; 
}

Help Version 19.0.2017.10.27

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