Procedure	SBC
Input:	A scene C.
Output:	Corrected scene Cc.
begin
S0.	set Cc= C;
S1.	standardize Cc to the standard intensity gray scale for the particular imaging Protocol P and body region R under consideration and output scene Cs;
S2.	determine tissue regions CB1, CB2, …, CBm by using fixed threshold intervals on Cs that are specific to P and R;
S3.	if CBi s determined in the previous iteration are insignificantly (< 0:1%) different from the current CBi s, stop;
S4.	else, estimate background variation in Cs as a scene Cbe, compute corrected scene Cc, and go to S1;
end