HistoContrast method (ILEADRasterProcess)

Visual Basic example

Visual C++ 5.0 example

Delphi 4 example

C++ Builder example

 

Syntax

short HistoContrast (ILEADRaster *pRaster, short iChange);

Overview

Refer to Changing Brightness and Contrast.

Remarks

Increases or decreases the contrast of the image in a bitmap, using a histogram to determine the median brightness.

This method finds the median brightness of the image; then brightens the pixels with values above the median and darkens the pixels with values below the median. This is more sophisticated (but slower) than the Contrast method, which uses the middle possible value (128) rather than finding the actual median.

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

This method does not support signed data images. It returns the error code ERROR_SIGNED_DATA_NOT_SUPPORTED if a signed data image is passed to this method.

This method supports signed images.

See Also

Elements:

Intensity method, GammaCorrect method, Contrast method, HistoEqualize method, StretchIntensity method

Topics:

Raster Images: Modifying Intensity Values

 

Raster Images: Using Histograms

 

Raster Images: Where the Region Preempts the Bitmap