Chung-Kennedy Filter
RGerkin
function /wave ChungKennedy(w,mm,kk,pp[,pis]) wave w // Data. variable mm // Analysis window length. variable kk // Number of filters. variable pp // An exponent. wave pis // The weights (pi_i) for the filters. Has length kk. if(paramisdefault(pis)) make /free/n=(kk) pis = 1 endif variable n = numpnts(w) make /free/n=(n,kk*2) estimates estimates[][0,kk] = mean(w,pnt2x(w,p-2^(q+1)),pnt2x(w,p-1)) // Forwards. estimates[][kk,] = mean(w,pnt2x(w,p+1),pnt2x(w,p+2^(q+1-kk))) // Backwards. make /free/n=(n,kk*2) weights make /free/n=(n,kk,mm) forwards = (w[p-r]-estimates[p-r][q])^2 make /free/n=(n,kk,mm) backwards = (w[p+r]-estimates[p+r][q+kk])^2 matrixop /free forwards = powR(sumbeams(forwards),-pp) matrixop /free backwards = powR(sumbeams(backwards),-pp) weights[][0,kk] = forwards[p][q]*pis[q] weights[][kk,] = backwards[p][q-kk]*pis[q-kk] // Normalize. matrixop /free sums = sumrows(weights) weights /= sums[p] matrixop /free result = sumrows(estimates * weights) return result end
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Biophys J. 2008 January 1; 94(1): 306–319.
Published online 2007 September 7. doi: 10.1529/biophysj.107.110601
PMCID: PMC2134886
A Comparison of Step-Detection Methods: How Well Can You Do?
Brian C. Carter,* Michael Vershinin,† and Steven P. Gross*†
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2134886/
for a discussion of different methods.
John Bechhoefer
Department of Physics
Simon Fraser University
Burnaby, BC, Canada
May 22, 2012 at 06:10 pm - Permalink