L_HistoEqualizeBitmap

#include "l_bitmap.h"

L_INT EXT_FUNCTION L_HistoEqualizeBitmap(pBitmap, nFlag)

pBITMAPHANDLE pBitmap;	/* pointer to the bitmap handle */
L_INT nFlag;	/* flag */

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

Parameter	Description
pBitmap	Pointer to the bitmap handle referencing the bitmap to be changed.
nFlag	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.

Returns

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

Comments

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

Previously this function only equalized the number of pixels per gray level, using a gray level representation of the image. This functionality is now obtained by passing GRAY_SPACE for nFlag.

For the best results, set nFlag to YUV_SPACE.

This function can process the whole image or a region of the image.

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 only in the Document/Medical toolkits.

Required DLLs and Libraries

LTIMG

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

Windows 95 / 98 / Me, Windows 2000 / XP, Windows CE.

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_ChannelMix, L_DeinterlaceBitmap, L_DesaturateBitmap, L_EdgeDetectStatisticalBitmap, L_LightControlBitmap, L_SmoothEdgesBitmap, L_LocalHistoEqualizeBitmap, L_AddWeightedBitmaps, L_ColorMergeBitmap, L_ColorSeparateBitmap, L_ConvertColorSpace, L_MultiplyBitmap, L_AutoColorLevelBitmap, L_ColorLevelBitmap, L_CorrelationBitmap, L_GrayScaleToDuotone, L_GrayScaleToMultitone, L_HolesRemovalBitmapRgn, L_SelectiveColorBitmap, L_SkeletonBitmap, L_ChangeHueSatIntBitmap, L_ColorReplaceBitmap, L_ColorThresholdBitmap, L_MathFunctionBitmap, L_SegmentBitmap, L_AdaptiveContrastBitmap, L_ApplyMathLogicBitmap, L_ColorIntensityBalance, L_ColorizeGrayBitmap, L_ContBrightIntBitmap, L_DigitalSubtractBitmap, L_DynamicBinaryBitmap, L_EdgeDetectEffectBitmap, L_FunctionalLightBitmap, L_MultiScaleEnhancementBitmap, L_SelectBitmapData, L_ShiftBitmapData
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 histogram equalization. */
BITMAPHANDLE LeadBitmap; /* Bitmap handle to hold the loaded image. */
/* Load the bitmap, keeping the bits per pixel of the file */
L_LoadBitmap (TEXT("IMAGE1.CMP"), &LeadBitmap, sizeof(BITMAPHANDLE), 0, ORDER_BGR, NULL, NULL);
/* Histogram equalize the bitmap */
L_HistoEqualizeBitmap(&LeadBitmap, YUV_SPACE );