Difference: 20151201MSciPhotometryAnalysisOb1part3 (7 vs. 8)

Revision 801 Dec 2015 - ElenaCukanovaite

Line: 1 to 1
 
META TOPICPARENT name="StewartBoogertPhotometry2015"

Floodfill algorithm improvements

  • To improve our algorithm we defined a star to be anything above 5 pixels in size.
Line: 29 to 29
 
  Minimum value Maximum Value Average Value
$\sigma_x$ 0.58 4.96 2.42
$\sigma_y$ 0.44 4.34 2.24
Added:
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A different way to estimate the mode

  • Building on what we did last week, instead of just splitting the image array into 4 separate arrays and finding the mode in each new array, we allowed for an arbitrary number of arrays that the main array can be split into.
  • A 2 by 2 splitting would be the following:
l1_quadrants_copy.png
  • If one splits the main image into as many arrays as there are elements in the original image, one would expect to get the original image back. This can be seen below:
full.png
  • Below are more examples:
85_by_85.png

30_by_30.png

17_by_17.png

  • If one takes a single mode over the entire image:
1_by_1.png
 

2D Fourier Transforms

  • Fourier transforms of such a star field will give regions in k space for both background and stars.
  • One of these can then be removed, leaving just stars or the background upon inverse Fourier transforming.
Line: 37 to 51
 
  • This shows a location 1 image, with its background now clustered around the edges.
FT_Loc1_nocut.png
  • This shows an attempt at removing the background from the image.
Changed:
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IFT_Loc1_bkgcut.png
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IFT_Loc1_bkgcut.png
 
  • This shows an attempt at removing the stars from the image. Note the image is logged, in order to better see the remnants of the stars.
Changed:
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IFT_Loc1_starcut.png

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IFT_Loc1_starcut.png

 

Stacking

  • In order to reduce errors and create better contrast between stars and background, a preliminary stacking effort was performed for 6 images taken in location 1, the result of which can be seen below.
Changed:
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  • From this it appears that although some movement is expected across the images, their overlay does not exhibit any easily noticable affects caused by this. Note however no scientific analysis of the effects has been conducted thus far.Stacking_ap_6.png
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  • From this it appears that although some movement is expected across the images, their overlay does not exhibit any easily noticable affects caused by this. Note however no scientific analysis of the effects has been conducted thus far.Stacking_ap_6.png
 -- ElenaCukanovaite - 01 Dec 2015

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Line: 65 to 78
 
META FILEATTACHMENT attachment="IFT_Loc1_bkgcut.png" attr="" comment="" date="1448987615" name="IFT_Loc1_bkgcut.png" path="Y:\Major Project\Figures\FT\IFT_Loc1_bkgcut.png" size="50810" user="zxap012" version="1"
META FILEATTACHMENT attachment="IFT_Loc1_starcut.png" attr="" comment="" date="1448987626" name="IFT_Loc1_starcut.png" path="Y:\Major Project\Figures\FT\IFT_Loc1_starcut.png" size="1349025" user="zxap012" version="1"
META FILEATTACHMENT attachment="Stacking_ap_6.png" attr="" comment="" date="1448989753" name="Stacking_ap_6.png" path="Y:\Major Project\Figures\Stacking\Stacking_ap_6.png" size="43202" user="zxap012" version="1"
Added:
>
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META FILEATTACHMENT attachment="l1_quadrants_copy.png" attr="" comment="" date="1449009728" name="l1_quadrants_copy.png" path="l1_quadrants copy.png" size="993054" user="zxap014" version="1"
META FILEATTACHMENT attachment="full.png" attr="" comment="" date="1449009820" name="full.png" path="full.png" size="46823" user="zxap014" version="1"
META FILEATTACHMENT attachment="85_by_85.png" attr="" comment="" date="1449009883" name="85_by_85.png" path="85_by_85.png" size="65293" user="zxap014" version="1"
META FILEATTACHMENT attachment="30_by_30.png" attr="" comment="" date="1449009943" name="30_by_30.png" path="30_by_30.png" size="54145" user="zxap014" version="1"
META FILEATTACHMENT attachment="17_by_17.png" attr="" comment="" date="1449009993" name="17_by_17.png" path="17_by_17.png" size="51834" user="zxap014" version="1"
META FILEATTACHMENT attachment="1_by_1.png" attr="" comment="" date="1449010045" name="1_by_1.png" path="1_by_1.png" size="49850" user="zxap014" version="1"
 
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