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imgGamma

Contents

Menu Information

Gamma

Brief Information

Apply gamma correction to image

Command Line Usage

1. imgGamma a:=1;

2. imgGamma a:=2.3 img:=mat(1) oimg:=mat(2);

Variables

Display
Name 		Variable
Name 		I/O
and
Type 		Default
Value 		Description
Gamma a

Input

double

1.0

Specifies the gamma value. It can be any number greater than 0.

Input Matrix img

Input

Image

<active>

Specifies the source image to be manipulated. The default input is the active image.

Output Image oimg

Output

Image

<input>

Specifies the output image. By default, the output image is the same as the input image.

See the syntax here.

Description

The imgGamma function adjusts the intensity of colors in a bitmap by changing the gamma constant that is used to map the intensity values. Note that a gamma value greater than 1 will in general lead to an intensity increase, while a gamma value less than 1 will cause the intensity to be reduced.

Examples

In this example, we use the imgGamma function to increase the intensity of the input image:

  1. When the input image is active, select Image: Adjustments: Gamma. This opens the dialog of the X-Function.
  2. In the X-Function dialog, change the settings as the screenshot below and click OK to close the dialog.
    Image:imgGamma_help_English_files_image002.jpg
    A new image is created. We can see that it is brighter than the original image.
Image:imgGamma_help_English_files_image004.jpg
Image:imgGamma_help_English_files_image006.jpg
The original image
The output image


Algorithm

The computation uses L_GammaCorrectBitmap() function from LEADTOOLS Main API. Please refer to the LEADTOOLS Main API Help file, Version 14 and read the L_GammaCorrectBitmap topic.

References

LEADTOOLS Main API Help file, Version 14

Related X-Functions

imgBrightness