2.6.1.13 imgLevel(Pro)

Menu Information

Image: Adjustments: Leveling

Brief Information

Adjust image levels

Additional Information

This feature is for OriginPro only.

Command Line Usage

1. imgLevel option:=contrast w:=20 b:=30;

2. imgLevel img:=1 option:=contrast w:=20 b:=30 oimg:=mat(2);

3. imgLevel img:=[Mbook1]Msheet1 oimg:=<new>;

X-Function Execution Options

Please refer to the page for additional option switches when accessing the x-function from script

Variables

Display Name	Variable Name	I/O and Type	Default Value	Description
Input Matrix	img	Input Image	<active>	Specifies the image to be manipulated. The default input is the active image.
Level Option	option	Input int	level	Specifies the leveling type. Option list L:Level Perform leveling on the individual R, G and B channels, treating each of the R, G and B channels as a individual entity. It introduces color cast on the image. C:Contrast Perform leveling on the MASTER channel (the grayscale values of the pixels). No color cast will be introduced. I:Intensity Perform leveling on the RGB channel (the sum of the R, G, and B channels). No color cast will be introduced.
WhiteClip(%)	w	Input double	0.5	Specifies the percentage of white pixels to clip from the input image.
BlackClip(%)	b	Input double	0.5	Specifies the percentage of black pixels to clip from the input 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.
Level Report	cl	Output ReportData	[<new>]<new>!	Specifies the leveling report.

Description

The imgLevel function applies leveling to an image. It makes the dark values darker and the light values lighter. It enhances the contrast and intensity by using the histogram of the image and a color distribution-based algorithm. There are three Leveling types in OriginPro:

• Level
• Contrast
• Intensity

This function allows you to choose the Leveling type, specify the percentage of white pixels and the percentage of black pixels. Choosing Level Report in the Leveling dialog can create a report for this function.

Another function named imgAutoLevel also can apply leveling to an image, but the percentage of white pixels and black pixels to clip from the input image is set as 5% automatically.

Examples

In this example, we use the imgLevel function to increase the contrast of the input image:

1. When the input image is active, select Image: Adjustments: Leveling. 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.
   
   A new image is created. We can see that the contrast is improved.

The original image	The output image

Algorithm

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

References

LEADTOOLS Main API Help file, Version 14

Related X-Functions

imgColorlevel, imgAutoLevel