MIPS EnhancerMIPS Enhancer

MIPS_Enhancer OverviewMIPS Data Processing and

Calibration WorkshopApril 12, 2004

How to Run How to Run MIPS_ENHANCERMIPS_ENHANCER

• Command line options– mips_enhancer –f filename.fits (40+ options)

• Namelist options– mips_enhancer –n namelist.in

What have we learned What have we learned since launch ?since launch ?

• Need to make MIPS_enhancer more efficient in terms of:– Memory – Speed

• Improve method of combing surface bright nesses.

Memory and SpeedMemory and Speed• Tiling

– -x #, -y #– Only operating on tile sub-pixels

• Do not hold mosaic in memory – -m

• Memory limited to current tile• Write tiles out • Stitch mosaic from tiles

– Necessary to change format of mosaic to limit memory needed.

• Primary header (history, information from first DCE)• Extensions: surface brightness, uncertainty, pixel flag,

overlap coverage)

Conserving Surface Conserving Surface BrightnessBrightness

• Improvements in:– Outlier rejection algorithm– Weighting overlapping pixels in

mosaic

Outlier Rejection Outlier Rejection AlgorithmAlgorithm

• For each sub-pixel there is a stack of overlapping BCD pixels.

Sub-Pixel Outlier RejectionSub-Pixel Outlier Rejection

N BCD overlapping pixel valuesStart Iteration i = 1.• Find the median value: Medianorg

• Find Standard Deviation: STDEVorg

• Find N differences: |(Medianorg – fluxk)|• Sort differences • Withhold 10% largest differences (minimum 1)• Find new median and standard deviation of remaining points:

Mediani, STDEVi

• Test Most deviant point:– (Fluxmost deviant point – Mediani)/STDEVi> Sigma Clipping (SC)– If reject – iterate

Outlier Rejection cont.Outlier Rejection cont.

• Continue iterating until:– Remain points < Minimum Points (SP)– Iteration # > Maximum # iterations

(SM)

– ((STDEVorg – STDEVnew)/STDEVorg )*100 > Sigma Tolerance (ST)

Variation on Outlier Variation on Outlier RejectionRejection

• Option: SKTest Most deviant point:

(Fluxmost deviant point – Mediani)/STDEVi> Sigma Clipping (SC)

• Option: SUInstead of using the standard deviation of stack: STDEVi

Combine in quadrature: uncertainty of BCD pixel and standard deviation of Median

Obsolete Outlier Rejection Obsolete Outlier Rejection optionsoptions

• Quartiles• May retire thresholding (t)

– (Fluxi/Median Flux) > t continue rejecting

– (Fluxi/Median Flux) < t stop rejection

Conserving Surface Conserving Surface BrightnessBrightness

• For each sub-pixel we have N BCD pixels overlapping– Surface Brightness of BCD– Uncertainty associated with surface

brightness– Overlap Area

• How do we combine information to conserve surface brightness in mosaic ?

DistortionsDistortions

Weighting MethodsWeighting Methods

Most probable value is a weighted average of points: wi xi/ wi

• W1= overlap area, uncertainties• W2=overlap area• W3=overlap area, S/N (SB/uncertainty)• W4=overlap area, SQRT(S/N)• W5=overlap area, SQRT(S)

Useful Options for Useful Options for MIPS_enhancerMIPS_enhancer

• -f filename (-i list of files)• -o output_name• -RR (remove rotation)• -s # (scale factor, recommended = 0.25)• dy (correct for distortion, default)• -x #, -y #, -m (memory & speed options)• -r # (70 microns, # BCDs to reject after stim,

recommened 1)• -IB (ignore bias boost, 24 microns, default)• -W2 (W1,W3,W4,W5) Weight options• -SC #, ST #, SP #, SM # SK, SU (outlier rejection options

Recommened:SC 4, ST 10, SP 3, SM 30, SK)• -FM (FD) sub-pixel flux weighted mean (median)• -D, -C, -FL (sets other appropriate options)

Near Term ImprovementsNear Term Improvements

• SED mode• Distortion (verify or tweak distortion

coefficients produced from CODE-V) • Study on surface brightness conservation

– Add weighting which only uses the number of reads that went into the slope determination.

– Develop testing routine to see how well we haveUse simulating routine (Emeric) to add sources to cal file.

• Move on to 160 micron data• Start enhancing framework

Suggestions ?Suggestions ?