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


#include "ltwrappr.h"

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



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

L_UINT uAmount

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

L_UINT uFlags

Value that indicates the adjustment method. Possible values are:

Value Meaning
ACE_EXP [0x0001] Apply exponential adjustment.
ACE_LIN [0x0002] Apply linear adjustment.


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


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.

Adaptive Contrast Function - Before

Adaptive Contrast Function - Before

Adaptive Contrast Function - After

Adaptive Contrast Function - After

View additional platform support for this Adaptive Contrast function.

Required DLLs and Libraries


Win32, x64.

See Also




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