CImage:SubBiasFrame

The SubBiasFrame method subtracts a bias frame image from the current image. The result replaces the current image.

Syntax

bResult = CImage:SubBiasFrame( Bias, pixel_type=nil )

bullet.gif    Bias is the CImage containing the bias frame.

bullet.gif    The optional pixel_type specifies the output pixel type as a number or string.

bullet.gif    On success, this method returns true.

bullet.gif    On failure, false. is returned.

Remarks

This method applies a bias frame correction to the image and updates the image header with the appropriate history and other keywords. The pixel type of the image may be changed as part of the correction, for example, to increase the precision of the bias removal procedure. Mira automatically handles mixing different pixel types between the source image and the bias frame.

Example

The following script loads an image and subtracts a bias frame. The output pixel type is changed to "float" to maintain precision of the correction process. In practice you might maintain the Bias frame in memory across a loop to process many images:

I = new_image()

-- create a new CImage

I:Open( sPath )

-- load the image from file sPath

Bias = new_image()

-- create a new CImage

Bias:Open( sBiasPath )

-- load the bias frame from file sBiasPath

I:SubBiasFrame(Bias,"float")

-- perform the operation on image I

I:Save()

 

I:delete()

 

Bias:delete()

 

Related Topics

CImage class, SubBiasVal, SubBiasRef


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