findramp

 function flag=findramp(v,flag,ramp)

 find ramps in the data vector v

 Input:
     v - data vector
  flag - if empty will be initialized to zeros
         otherwise it is bad values within v
  ramp - ramp threshold.  or maximum rate of change (slope)

 Output;
  flag - location of bad points

 Michael Loh

0001 function flag=findramp(v,flag,ramp)
0002 
0003 % function flag=findramp(v,flag,ramp)
0004 %
0005 % find ramps in the data vector v
0006 %
0007 % Input:
0008 %     v - data vector
0009 %  flag - if empty will be initialized to zeros
0010 %         otherwise it is bad values within v
0011 %  ramp - ramp threshold.  or maximum rate of change (slope)
0012 %
0013 % Output;
0014 %  flag - location of bad points
0015 %
0016 % Michael Loh
0017 
0018 if (isempty(flag))
0019   flag=zeros(size(v));
0020 end
0021 
0022 difv=diff(v);
0023 
0024 f=find(abs(difv)<ramp);
0025 difv(f)=0;
0026 
0027 % get sign info
0028 phs=sign(difv);
0029 
0030 % find consecutive signs
0031 % first do positive
0032 [s,e]=group(phs>0);
0033 
0034 ramp=find((e-s)>=1);
0035 for i=1:length(ramp)
0036   flag(s(ramp(i))+1:e(ramp(i)))=1;
0037 end
0038 
0039 % now do neg
0040 [s,e]=group(phs<0);
0041 
0042 ramp=find((e-s)>=1);
0043 for i=1:length(ramp)
0044   flag(s(ramp(i))+1:e(ramp(i)))=1;
0045 end