-- AaronAndrews - 24 Nov 2016

Simulation: ( Simulation_test10.py.txt)

- Made example star field with no background - used M103 data, 108 stars total. ( M103_Simtest_noBG.txt)
- Modified simulation to generate position-varying background. Mean and standard deviation can be changed independantly.
- For testing, generated means and standard deviations using following functions ('inclined planes'): ( M103_BG_1.txt)
- Mean = 900 + (0.5)x + (0.005)y
- S.D. = 5 + (0.01)x + (0.01)y
- x,y = pixel positions

- Could also generate with more complicated functions - e.g. taylor expansion.
- Used mean and S.D. per pixel to generate random gaussian distributed value for background, added to example star field.
- Size of the median filter box as a function of the fitted mean:
- Used mean and S.D. per pixel to generate random gaussian distributed value for background, added to example star field:

- Ran a median filter (i.e. finding median of a box, size n, centered on each pixel) for different box sizes, on the simulated background+stars.
- Subtracted the median image from original, to remove background. Then created histograms of resulting pixel values.
- Histograms assumed to be gaussian - found sigma and mean for each.
- Plotted sigmas and means in relation to box size.

- Median, sigma and mean plots on simulated M103 with background, 65 width box:

- Median, sigma and mean plots on simulated background, 65 width box:

- Histograms showing the simulated background minus the median filter of the background for box sizes 201 and 11
- For the 201 box size the fitted mean pixel value is 0.56057, the standard deviation is 15.992
- For the 11 box size the fitted mean pixel value is 0.40479, the standard deviation is 15.634

- Histograms showing the simulated background with stars minus the median filtered version for box sizes 301 and 15
- For the 201 box size the fitted mean pixel value is 0.15810, the standard deviation is 16.386
- For the 11 box size the fitted mean pixel value is 0.38595, the standard deviation is 15.972

- Size of the median filter box as a function of the fitted mean and the fitted standard deviation:

- Images showing the simulated background minus the median filter of the background for box sizes 201 and 11:

- Images showing the simulated background with stars minus the median filter of the background for box sizes 201 and 11:

I | Attachment | History | Action | Size | Date | Who | Comment |
---|---|---|---|---|---|---|---|

txt | BackgroundCode.txt | r1 | manage | 5.5 K | 25 Nov 2016 - 13:50 | AnishaVadher | |

txt | Background_Analysis.txt | r1 | manage | 2.3 K | 25 Nov 2016 - 13:07 | LauraBevilacqua | Background analysis code including median filter and histogram making |

png | BoxVsMean.png | r1 | manage | 23.5 K | 25 Nov 2016 - 11:14 | AnishaVadher | Size of the median filter box as a function of the fitted mean |

png | BoxVsSigma.png | r1 | manage | 26.1 K | 25 Nov 2016 - 11:16 | AnishaVadher | Size of the median filter box as a function of the fitted standard deviation |

fits | M103_BG_1.fits | r1 | manage | 12195.0 K | 25 Nov 2016 - 11:05 | AaronAndrews | M103 sim. - BG only |

png | M103_BG_1.png | r2 r1 | manage | 421.7 K | 25 Nov 2016 - 13:26 | AaronAndrews | M103 sim. - final simulated background |

txt | M103_BG_1.txt | r1 | manage | 0.2 K | 25 Nov 2016 - 11:06 | AaronAndrews | M103 sim. - BG parameters |

png | M103_BGfinal_1.png | r1 | manage | 421.7 K | 25 Nov 2016 - 13:29 | AaronAndrews | M103 sim. - final background |

png | M103_BGmean_1.png | r1 | manage | 49.0 K | 25 Nov 2016 - 13:24 | AaronAndrews | M103 sim. - BG mean |

png | M103_BGsd_1.png | r1 | manage | 70.0 K | 25 Nov 2016 - 13:24 | AaronAndrews | M103 sim. - BG standard deviation |

png | M103_Background-Median_im.png | r1 | manage | 1698.3 K | 25 Nov 2016 - 12:52 | LauraBevilacqua | |

png | M103_BackgroundOnly_Hist.png | r1 | manage | 192.6 K | 25 Nov 2016 - 12:07 | LauraBevilacqua | |

png | M103_BackgroundStars-Median_im.png | r1 | manage | 354.1 K | 25 Nov 2016 - 12:52 | LauraBevilacqua | |

png | M103_BackgroundStars_Hist.png | r1 | manage | 186.3 K | 25 Nov 2016 - 12:07 | LauraBevilacqua | |

png | M103_Sim_11size_NoBackground.png | r1 | manage | 91.3 K | 25 Nov 2016 - 12:07 | LauraBevilacqua | |

png | M103_Sim_201size_NoBackground.png | r1 | manage | 91.4 K | 25 Nov 2016 - 12:07 | LauraBevilacqua | |

fits | M103_Simtest_noBG.fits | r1 | manage | 12195.0 K | 25 Nov 2016 - 11:04 | AaronAndrews | M103 sim. - stars only |

txt | M103_Simtest_noBG.txt | r1 | manage | 8.0 K | 25 Nov 2016 - 11:06 | AaronAndrews | M103 sim. - Star parameters |

fits | M103_starsBG_1.fits | r1 | manage | 12195.0 K | 25 Nov 2016 - 11:04 | AaronAndrews | M103 sim. - stars+BG |

png | M103_starsBG_1_GS.png | r1 | manage | 1312.1 K | 25 Nov 2016 - 13:30 | AaronAndrews | M103 sim - stars + BG greyscale |

txt | Simulation_test10.py.txt | r1 | manage | 28.8 K | 25 Nov 2016 - 11:02 | AaronAndrews | Simulation program 10 (+ median analysis) |

png | StatsPlotsM103SBG.png | r1 | manage | 171.0 K | 25 Nov 2016 - 12:12 | AnishaVadher | Median, sigma and mean plots on simulated M103 with background |

png | StatsPlotsSimulatedBG.png | r1 | manage | 295.5 K | 25 Nov 2016 - 12:15 | AnishaVadher | Median, sigma and mean plots on simulated background |

png | compare.png | r1 | manage | 119.8 K | 25 Nov 2016 - 12:36 | AnishaVadher | Size of the median filter box as a function of the fitted mean and the fitted standard deviation |

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Topic revision: r13 - 25 Nov 2016 - AnishaVadher

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