CImCombine:Sdev

CImCombine:Sdev

The Sdev method creates an image who's pixel values are the standard deviation of values among all images at each point.

Syntax

CImage = CImCombine:Sdev( CImageSet )

CImageSet contains the collection of images to be combined.
CImage is a new image created by this method.
On success, this method returns a new CImage.
On failure, this method returns nil.

Remarks

Each pixel in the output image is the standard deviation of values at the same location in all the images of the CImageSet. This is not an image like each of the source images, but is a statistical map over the surface of the collection of images. Depending upon the images and the application, you may or may not wish to normalize the images before computing the range.

Example

Suppose a CImageSet named S exists. The following script fragment combines the images by the Sdev method after normalizing their luminance by the median statistic computed inside the central 10% of the image:

C = CImCombine:new()	-- create a CImCombine object
R = CRect:new(10,50,10,50)	-- central 10% of the image
C:SetRelRect( R )	-- specify CImage and CRect to measure
C:SetNormStat("median")	-- use the median as the normalization statistic
C:SetNormMethod("scale")	-- scale to normalize the image set
I = C:Sdev( S )	-- combine the image set and return a new image
I:Display()	-- show the new image
C:delete()	-- when done with S, remove it from memory