#include "l_bitmap.h"
L_LTIMGCLR_API L_INT L_LocalHistoEqualizeBitmap(pBitmap, nWidth, nHeight, nxExt, nyExt, uType, uSmooth, uFlags)
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.
Pointer to the bitmap handle referencing the bitmap to be changed.
The width of the local histogram equalizer rectangle in pixels. The width should be more than zero.
The height of the local histogram equalizer rectangle in pixels. The height should be more than zero.
The extension of the width of the local histogram equalizer rectangle, in pixels.
The extension of the height of the local histogram equalizer rectangle, in pixels.
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. |
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.
Reserved for future use. Must be 0.
Value | Meaning |
---|---|
SUCCESS | The function was successful. |
< 1 | An error occurred. Refer to Return Codes. |
Required DLLs and Libraries
Win32, x64, Linux.
For complete sample code, refer to the CHILD.C module of the DEMO example.
This example loads a bitmap and applies local histogram equalization.
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;
}
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