L_MedianFilterBitmap

#include "l_bitmap.h"

L_LTIMGCOR_API L_INT L_MedianFilterBitmap(pBitmap, uDim, uFlags)

pBITMAPHANDLE pBitmap;	pointer to the bitmap handle
L_UINT uDim;	dimensions of the neighborhood (uDim x uDim), in pixels
L_UINT32 uFlags;	flags

Changes the color of each pixel in a bitmap to the median color of pixels in its neighborhood. This is similar to the L_AverageFilterBitmap function, but it is used for noise reduction, rather than a blur effect.

Parameter	Description
pBitmap	Pointer to the bitmap handle referencing the bitmap to be converted.
uDim	Dimensions of the neighborhood used for filtering (uDim x uDim), in pixels.
uFlags	Reserved for future use. Must be 0.

Returns

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

Comments

You control the effect by specifying the size of the neighborhood that is used for calculating the median value. For 8x8, pass 8 in the uDim parameter.

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

This function supports 12 and 16-bit grayscale and 48 and 64-bit color images. Support for 12 and 16-bit grayscale and 48 and 64-bit color images is available in the Document and Medical Imaging toolkits.

If the bitmap has a region, this function works only on the region. If the bitmap does not have a region, this function works on the entire bitmap.

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

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

For complete sample code, refer to the CHILD.C module of the DEMO example. This example loads a bitmap and applies an median filter.

#define MAKE_IMAGE_PATH(pFileName) TEXT("C:\\Users\\Public\\Documents\\LEADTOOLS Images\\")pFileName 
L_INT MedianFilterBitmapExample(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("ImageProcessingDemo\\NaturalFruits.jpg")), &LeadBitmap, sizeof(BITMAPHANDLE), 0, ORDER_BGR, NULL, NULL); 
   if(nRet !=SUCCESS) 
      return nRet; 
   /* Apply a median filter  with a neighborhood of 3x3 pixels */ 
   nRet = L_MedianFilterBitmap(&LeadBitmap, 3 , 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; 
}

Help Version 19.0.2017.10.27

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LEADTOOLS Raster Imaging C API Help

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LEADTOOLS Raster Imaging Features

Redistributables/Files To Be Included With Your Application

Functions:	L_SharpenBitmap, L_PosterizeBitmap, L_MosaicBitmap, L_EmbossBitmap, L_AverageFilterBitmap, L_AddBitmapNoise, L_IntensityDetectBitmap, L_SpatialFilterBitmap, L_BinaryFilterBitmap, L_MaxFilterBitmap, L_MinFilterBitmap, L_OilifyBitmap, L_SolarizeBitmap, L_DlgMedian, L_WindowLevel, L_BricksTextureBitmap, L_DeskewBitmap, L_DiffuseGlowBitmap, L_GlowFilterBitmap, L_HalfTonePatternBitmap, L_HighPassFilterBitmap, L_MaskConvolutionBitmap, L_PerspectiveBitmap, L_PlasmaFilterBitmap, L_PointillistBitmap, L_FragmentBitmap, L_HighPassFilterBitmap, L_UnsharpMaskBitmap
Topics:	Raster Image Functions: Filtering Images
	Removing Noise