SMART Error and BMASK Plane during Image Operations

SMART Error and BMASK Plane during Image Operations

For an explanation of the Error and BMASK planes see : Error and BMASK Plane Processing

How they are processed during SMART Image Operations is described below.

Error Plane Processing in Image Operations

Error plane processing in Image Operations is dependent on the "!sm_eplane" setting of the User Parameters.
The value of "!sm_eplane" is displayed at the top of the Image Operations window.
It has 2 possible values :

• "0 - SMART Constructed Error Plane"
• "1 - SSC Error Plane"

The effects of "!sm_eplane" setting on error plane processing are :

Image Operation	"!sm_eplane" Setting	Error plane of resultant image
Combine : Add	SMART Constructed Error Plane	Standard deviation of flux values in data plane(s) of input image(s)
Combine : Add	SSC Error Plane	Quadrature addition of error plane values from input image(s)
Combine : Mean	SMART Constructed Error Plane	Standard deviation of flux values in data plane(s) of input image(s)
Combine : Mean	SSC Error Plane	Quadrature addition of error plane values from input image(s)
Combine : Median	SMART Constructed Error Plane	Standard deviation of flux values in data plane(s) of input image(s) * 1.253 (For explanation see Sampling distribution of median.)
Combine : Median	SSC Error Plane	Quadrature addition of error plane values from input image(s)
Combine : Median Filter	SMART Constructed Error Plane	Calculate the mean of the selected images and filter to remove NaNs?.
Combine : Median Filter	SSC Error Plane	Calculate the mean of the selected images and filter to remove NaNs?.
Combine : Fair CoAdd?	SMART Constructed Error Plane	Algorithm Specific (Image Operations - Fair CoAdd?)
Combine : Fair CoAdd?	SSC Error Plane	Algorithm Specific (Image Operations - Fair CoAdd?)
Combine : Weighted Mean	SMART Constructed Error Plane	Algorithm Specific (Image Operations - Weighted Mean)
Combine : Weighted Mean	SSC Error Plane	Algorithm Specific (Image Operations - Weighted Mean)
Arithmetics	SMART Constructed Error Plane	Standard deviation of flux values in data plane(s) of input image(s)
Arithmetics	SSC Error Plane	Quadrature addition of error plane values from input image(s)
Multiple Subtraction	SMART Constructed Error Plane	Quadrature addition of error plane values from input image(s)
Multiple Subtraction	SSC Error Plane	Quadrature addition of error plane values from input image(s)
Multiple Division	SMART Constructed Error Plane	Quadrature addition of error plane values from input image(s)
Multiple Division	SSC Error Plane	Error plane (dz) calculated by the formula : (dz^2)/(z^2) = ((dx^2)/(x^2)) + ((dy^2)/(y^2)) where : x, y - input data values dx, dy - input error values z = (x * y)^2

NOTE :
The SMART developers have found the following book very helpful for its explanations about the statistical combinations of errors :

"Data reduction and error analysis for the physical sciences" by Philip R. Bevington and D. Keith Robinson.

Third edition published by McGraw?-Hill, Boston, 2003.

BMASK Plane Processing in Image Operations

BMASK plane processing in Image Operations :

Image Operation	BMASK plane of resultant image
Combine : Add	Combined logical "or" of input BMASK(s)
Combine : Mean	Combined logical "or" of input BMASK(s)
Combine : Median	Combined logical "or" of input BMASK(s)
Combine : Median Filter	Algorithm Specific
Combine : Fair CoAdd?	Algorithm Specific
Combine : Weighted Mean	Algorithm Specific
Arithmetics	Combined logical "or" of input BMASK(s)
Multiple Subtraction	Combined logical "or" of input BMASK(s)
Multiple Division	Combined logical "or" of input BMASK(s)