LBitmap::AdaptiveContrast

#include "ltwrappr.h"

virtual L_INT LBitmap::AdaptiveContrast (uDim, uAmount, uFlags)

L_UINT uDim;

/* dimensions of the neighborhood (uDim x uDim), in pixels */

L_UINT uAmount;

/* adjustment factor */

L_UINT uFlags;

/* flag */

Performs adaptive contrast enhancement (ACE) to regions that are originally low in contrast.

Parameter

Description

uDim

Dimensions of the neighborhood used for filtering (uDim x uDim), in pixels.

uAmount

Value that represents an adjustment factor. Its range starts from 100 and has no upper limit.

uFlags

Value that indicates the adjustment method. Possible values are:

 

Value

Meaning

 

ACE_EXP

[0x0001] Apply exponential adjustment.

 

ACE_LIN

[0x0002] Apply linear adjustment.

Returns

SUCCESS

The function was successful.

< 1

An error occurred. Refer to Return Codes.

Comments

Adaptive contrast enhancement (ACE) adjusts bitmap contrast by giving more contrast to areas which are originally low in contrast. This is different from histogram-based techniques which are based on all bitmap pixels (the histogram itself).

Local histogram equalization is another technique that can be used to reveal detail of areas, since it depends on area pixels only. Use LBitmap::LocalHistoEqualize to perform a local histogram equalization.

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

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.

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

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.

See Also

Functions:

LBitmap::AdjustTint, LBitmap::GammaCorrectExt, LBitmap::HistoEqualize, LBitmap::ChangeContrast, LBitmap::ChangeIntensity, LBitmap::GammaCorrect, LBitmap::HistoContrast, LBitmap::StretchIntensity, LBitmap::Invert, LBitmap::ChangeHue, LBitmap::ChangeSaturation, LBitmapBase::Fill, LBitmapBase::GetPixelColor, LBitmapBase::PutPixelColor, LBitmap::GetHistogram, LBitmap::WindowLevel, LBitmap::WindowLevelExt, LBitmap::LocalHistoEqualize, LBitmap::ChangeHueSatInt

Topics:

Raster Image Functions: Modifying Intensity Values

 

Changing Brightness and Contrast

 

Raster Image Functions: Changing Brightness and Contrast

Example

L_INT LBitmap__AdaptiveContrastExample(LBitmap *pLeadBitmap) 
{
   
   /* This example applies Adaptive Contrast Enhancement */
   /* Apply Adaptive Contrast Enhancement */
   return pLeadBitmap->AdaptiveContrast(9, 200, ACE_LIN); 
}