Difference: 20151201MSciPhotometryAnalysisOb1part3 (1 vs. 9)

Revision 902 Dec 2015 - DavidHadden

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: 55 to 55
 
  • 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.

IFT_Loc1_starcut.png

Changed:
<
<

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.
  • 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

META FILEATTACHMENT attachment="Floodfill_original.png" attr="" comment="" date="1448970468" name="Floodfill_original.png" path="Y:\Major Project\Figures\Flood_Fill\Floodfill_original.png" size="89931" user="zxap012" version="1"

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:
>
>

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:
<
<		IFT_Loc1_bkgcut.png
>
>		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:
<
<

IFT_Loc1_starcut.png

>
>

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:
<
<
  • 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
>
>
  • 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

META FILEATTACHMENT attachment="Floodfill_original.png" attr="" comment="" date="1448970468" name="Floodfill_original.png" path="Y:\Major Project\Figures\Flood_Fill\Floodfill_original.png" size="89931" user="zxap012" version="1"
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:
>
>
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"

Revision 701 Dec 2015 - DavidHadden

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: 39 to 39
 
  • This shows an attempt at removing the background from the image.
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:
<
<		IFT_Loc1_starcut.png
>
>

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.
  • 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
Line: 60 to 64
 
META FILEATTACHMENT attachment="FT_Loc1_nocut.png" attr="" comment="" date="1448987605" name="FT_Loc1_nocut.png" path="Y:\Major Project\Figures\FT\FT_Loc1_nocut.png" size="1232624" user="zxap012" version="1"
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"
Added:
>
>
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"

Revision 601 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: 35 to 35
 
  • Initial attempts of this can be seen below.

  • This shows a location 1 image, with its background now clustered around the edges.
Changed:
<
<		FT_Loc1_nocut.png
>
>		FT_Loc1_nocut.png
 
  • This shows an attempt at removing the background from the image.
Changed:
<
<		 IFT_Loc1_bkgcut.png
>
>		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:
<
<		 IFT_Loc1_starcut.png
>
>		IFT_Loc1_starcut.png
  -- ElenaCukanovaite - 01 Dec 2015

Revision 501 Dec 2015 - DavidHadden

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:
>
>

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.
  • Initial attempts of this can be seen below.

  • 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.

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.

IFT_Loc1_starcut.png

  -- ElenaCukanovaite - 01 Dec 2015
Line: 46 to 59
 
META FILEATTACHMENT attachment="latex7be20fa2e2770b23d94a4539527c204b.png" attr="h" comment="" date="1448984177" name="latex7be20fa2e2770b23d94a4539527c204b.png" user="zxap014" version="1"
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Added:
>
>
META FILEATTACHMENT attachment="FT_Loc1_nocut.png" attr="" comment="" date="1448987605" name="FT_Loc1_nocut.png" path="Y:\Major Project\Figures\FT\FT_Loc1_nocut.png" size="1232624" user="zxap012" version="1"
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"

Revision 401 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: 14 to 14
 \begin{equation} y_{\rm center} = \frac{\sum_{i = 1}^N y_i p_i}{\sum_{i=1}^N p_i}\end{equation}

%ENDLATEX%

Changed:
<
<
  • where $x_{\rm center}$ and $y_{\rm center}$ are the x,y centers and $x_i$ and $y_i$ are the x and y coordinates of the individual pixels of the star and $p_i$ is the pixel value of the pixel.
>
>
  • where $x_{\rm center}$ and $y_{\rm center}$ are the x,y centers and $x_i$ and $y_i$ are the x and y coordinates of the individual pixels of the star and $p_i$ is the pixel value of the pixel, and $N$ is the total number of pixels of a given star.
 
  • An example of a found star center is shown below:
center_improved.png
Added:
>
>
  • The standard deviations were found using the following equations:
\begin{equation} \sigma_x = \sqrt{\frac{\sum_{i = 1}^N (x_i - x_{\rm center})^2 p_i}{\sum_{i=1}^N p_i}}\end{equation} \begin{equation} \sigma_y = \sqrt{\frac{\sum_{i = 1}^N (y_i - y_{\rm center})^2p_i}{\sum_{i=1}^N p_i}}\end{equation} <br />

  • where $\sigma_x$ and $\sigma_y$ are the standard deviations in x and y.
  • Some information about found sigmas for all stars in this image:
  Minimum value Maximum Value Average Value
$\sigma_x$ 0.58 4.96 2.42
$\sigma_y$ 0.44 4.34 2.24
  -- ElenaCukanovaite - 01 Dec 2015
Line: 30 to 42
 
META FILEATTACHMENT attachment="latex9938e249002f535a9bca46269e83cee5.png" attr="h" comment="" date="1448976780" name="latex9938e249002f535a9bca46269e83cee5.png" user="zxap014" version="1"
META FILEATTACHMENT attachment="center_improved.png" attr="" comment="" date="1448976882" name="center_improved.png" path="center_improved.png" size="70184" user="zxap014" version="1"
META FILEATTACHMENT attachment="interesting_stars.png" attr="" comment="" date="1448977107" name="interesting_stars.png" path="interesting_stars.png" size="63688" user="zxap014" version="1"
Added:
>
>
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Revision 301 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.
Changed:
<
<
  • It seems that all hot pixels were removed
>
>
  • It seems that all hot pixels were removed:
Floodfill_original.png

floodfill_imrpoved.png

  • Found an interesting structure:
interesting_stars.png
  • To improve center founding, we found x and y weighted averages, such that:
\begin{equation} x_{\rm center} = \frac{\sum_{i = 1}^N x_i p_i}{\sum_{i=1}^N p_i}\end{equation} \begin{equation} y_{\rm center} = \frac{\sum_{i = 1}^N y_i p_i}{\sum_{i=1}^N p_i}\end{equation}
  • where $x_{\rm center}$ and $y_{\rm center}$ are the x,y centers and $x_i$ and $y_i$ are the x and y coordinates of the individual pixels of the star and $p_i$ is the pixel value of the pixel.
  • An example of a found star center is shown below:
center_improved.png
 -- ElenaCukanovaite - 01 Dec 2015

META FILEATTACHMENT attachment="Floodfill_original.png" attr="" comment="" date="1448970468" name="Floodfill_original.png" path="Y:\Major Project\Figures\Flood_Fill\Floodfill_original.png" size="89931" user="zxap012" version="1"
Added:
>
>
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META FILEATTACHMENT attachment="interesting_stars.png" attr="" comment="" date="1448977107" name="interesting_stars.png" path="interesting_stars.png" size="63688" user="zxap014" version="1"

Revision 201 Dec 2015 - DavidHadden

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.
  • It seems that all hot pixels were removed
-- ElenaCukanovaite - 01 Dec 2015 \ No newline at end of file
Added:
>
>
META FILEATTACHMENT attachment="Floodfill_original.png" attr="" comment="" date="1448970468" name="Floodfill_original.png" path="Y:\Major Project\Figures\Flood_Fill\Floodfill_original.png" size="89931" user="zxap012" version="1"

Revision 101 Dec 2015 - ElenaCukanovaite

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

Floodfill algorithm improvements

  • To improve our algorithm we defined a star to be anything above 5 pixels in size.
  • It seems that all hot pixels were removed
-- ElenaCukanovaite - 01 Dec 2015
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