TIEVisionImage.clahe

Declaration

procedure clahe(dst: TIEVisionImage; clipLimit: Double = 40.0; tileWidth: int32_t = 8; tileHeight: int32_t = 8); overload; safecall;
procedure clahe(clipLimit: Double = 40.0; tileWidth: int32_t = 8; tileHeight: int32_t = 8); overload; safecall;

Description

Contrast Limited Adaptive Histogram Equalization (CLAHE). Unlike equalizeHistogram, CLAHE equalizes locally in tiles and clips the histogram to reduce noise amplification.
First overload places the result into destination object.
Second overload updates the current image.

Gray images must be 8-bit or 16-bit single-channel. Color images (8-bit 3 or 4 channel) are converted to Lab, CLAHE is applied to the L channel, then converted back. Alpha is preserved on 4-channel images. 1-bit images are not supported (convert to 8-bit first).

Parameter	Description
dst	Container for the destination image
clipLimit	Threshold for contrast limiting. Higher values give stronger contrast (default 40)
tileWidth	Tile grid width. The image is divided into tileWidth x tileHeight tiles (default 8)
tileHeight	Tile grid height (default 8)

Demo

Demos\ImageEditing\EveryMethod\EveryMethod.dpr

Examples

Also see: Automated Samples

// Local contrast enhancement
ImageEnView1.IEBitmap.GetIEVisionImage().clahe( 2.0, 8, 8 );
ImageEnView1.Update();

// Load test image
ImageEnView1.IO.LoadFromFile( 'D:\TestImage.jpg' );

// Apply Contrast Limited Adaptive Histogram Equalization
ImageEnView1.IEBitmap.GetIEVisionImage().clahe( 40, 8, 8 );
ImageEnView1.Update(); // Show changes in our viewer

TIEVisionImage.clahe