Difference: 20151101_MSciSpectrocopyLab (1 vs. 5)

Revision 503 Nov 2016 - JamesAngthopo

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META TOPICPARENT name="StewartBoogertSpectroscopy2015"
Hot Pixels

Revision 404 Nov 2015 - JosephBayley

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META TOPICPARENT name="StewartBoogertSpectroscopy2015"
Hot Pixels
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  • Focus_fit.png:
    Focus_fit.png

  • Angle_fit.png:
    Angle_fit.png
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Mapping grating micrometer position to wavelength

  • Initiall two plot were made of cadmiums spectrum at 3.5 mm and 4.0 mm,
  • 3.5_4.0_pixel.png:
    3.5_4.0_pixel.png

  • The pixel distance between the same peak in each frame was found to be 277.
  • By then finding the initial plot in nm, the pixel distance between the same peak could be subtracted to get the correct value as shown below:

  • 3.5_4.0_wavelength.png:
    3.5_4.0_wavelength.png
  • By then applying this across the all of the frames of the spectrum, the spectrum for cadmium was obtained, however the values are not quite correct:
  • Cadmium_spectrum.png:
    Cadmium_spectrum.png
 -- AshleaKemp - 02 Nov 2015

META FILEATTACHMENT attachment="Hotpixels.png" attr="h" comment="Dark frame spectrum" date="1446428380" name="Hotpixels.png" path="Hotpixels.png" size="34303" user="zxap013" version="1"
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META FILEATTACHMENT attachment="Angle_fit.png" attr="h" comment="" date="1446592760" name="Angle_fit.png" path="Angle_fit.png" size="58841" user="zxap044" version="1"
META FILEATTACHMENT attachment="Focus_fit.png" attr="h" comment="" date="1446592759" name="Focus_fit.png" path="Focus_fit.png" size="61666" user="zxap044" version="1"
META FILEATTACHMENT attachment="latexd9ffb6fa7a3af9b5c4a1740e4aa755b7.png" attr="h" comment="" date="1446593566" name="latexd9ffb6fa7a3af9b5c4a1740e4aa755b7.png" user="zxap044" version="1"
Added:
>
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META FILEATTACHMENT attachment="3.5_4.0_pixel.png" attr="h" comment="" date="1446621936" name="3.5_4.0_pixel.png" path="3.5_4.0_pixel.png" size="59458" user="zxap044" version="1"
META FILEATTACHMENT attachment="3.5_4.0_wavelength.png" attr="h" comment="" date="1446621935" name="3.5_4.0_wavelength.png" path="3.5_4.0_wavelength.png" size="61639" user="zxap044" version="1"
META FILEATTACHMENT attachment="Cadmium_spectrum.png" attr="h" comment="" date="1446622544" name="Cadmium_spectrum.png" path="Cadmium_spectrum.png" size="42520" user="zxap044" version="1"

Revision 303 Nov 2015 - JosephBayley

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META TOPICPARENT name="StewartBoogertSpectroscopy2015"
Hot Pixels
Changed:
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  • Analysed a two dark frames to find locations of hot pixels. 1st Dark frame had a 1 second exposure time at a temperature of 20 degrees. 2nd Dark frame had a second exposure time at a temperature at 5 degrees.
  • As can be seen from both spectrums below, the 2nd dark frame has comparatively less background fluctuations due to the lower temperature.
  • A code was written to print the index of the pixel values which exceed the mean+standard deviation of the 1D array obtained from summing each column of pixels downwards. Pixel values exceeding this limit are considered signicantly above the background.
  • Spectrum of dark frame analysed with spikes indicating hot pixels:
Hotpixels.png
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*The background data of a dark frame was plotted at an exposure of 2 s and a temperature of 10deg.
 
Changed:
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3 second dark frame
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  • Background_hot.png:
    Background_hot.png
 
Changed:
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  • Pixel values exceeding this limit were located at pixel positions 90, 180, 222, 407, 490, 497, 617 along the x axis for the 1st dark frame.
  • Pixel values exceeding this limit were located at positions 90, 222, 407, 617 along x axis for 2nd dark frame - conclude these are hot pixels.
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  • The large spikes in the plot are believed to be 'hot pixels'
  • By finding the standard deviation and mean of the background data, any points that were larger than the standard deviation plus the mean were recorded. This process is repeated for 2 dark frames so that the hot pixels can be determined.
  • For the 1st frame, pixel values exceeding this limit were located at pixel positions 90, 180, 222, 407, 490, 497, 617 along the x axis.
  • For the second frame, pixel values exceeding this limit were located at positions 90, 222, 407, 617 along x axis.
  • We can then conclude that the repeated positions are 'Hot pixels'.
  • The 'hot pixels' were then set to a value of the average of its surrounding pixels. This then gave a plot of:

  • Background_nohot.png:
    Background_nohot.png

  • The background can be seen to be rising in intensity towards one side of the camera. Not sure as to why?
 Finding the best focus distance/camera angle

  • After meeting on 28/10/15, decided to fit a hyperbole to the standard deviation against focus distance plot and a sine function to the standard deviation against camera angle plot - these fits were a much better fit than the parabolas.
Changed:
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  • Chi square value for focus = 0.00665
  • Chi square value for angle = 0.000382
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  • Focus : $\chi ^2$ = 0.00665
  • Angle : $\chi ^2$ = 0.000382
 
  • Still need to adjust errors - will ask Prof Cowan in own time
Changed:
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Focus.png

Angle.png

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>
  • Focus_fit.png:
    Focus_fit.png
 
Added:
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  • Angle_fit.png:
    Angle_fit.png
 -- AshleaKemp - 02 Nov 2015
Changed:
<
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META FILEATTACHMENT attachment="Hotpixels.png" attr="" comment="Dark frame spectrum" date="1446428380" name="Hotpixels.png" path="Hotpixels.png" size="34303" user="zxap013" version="1"
META FILEATTACHMENT attachment="Focus.png" attr="" comment="stdev versus focus" date="1446465546" name="Focus.png" path="Focus.png" size="32705" user="zxap013" version="2"
META FILEATTACHMENT attachment="Angle.png" attr="" comment="stdev versus angle" date="1446465524" name="Angle.png" path="Angle.png" size="34590" user="zxap013" version="2"
META FILEATTACHMENT attachment="Hot.png" attr="" comment="dark frame 2s 5 deg" date="1446429347" name="Hot.png" path="Hot.png" size="36913" user="zxap013" version="1"
META FILEATTACHMENT attachment="g.png" attr="" comment="3 second dark frame" date="1446430040" name="g.png" path="g.png" size="37628" user="zxap013" version="1"
>
>
META FILEATTACHMENT attachment="Hotpixels.png" attr="h" comment="Dark frame spectrum" date="1446428380" name="Hotpixels.png" path="Hotpixels.png" size="34303" user="zxap013" version="1"
META FILEATTACHMENT attachment="Focus.png" attr="h" comment="stdev versus focus" date="1446465546" name="Focus.png" path="Focus.png" size="32705" user="zxap013" version="2"
META FILEATTACHMENT attachment="Angle.png" attr="h" comment="stdev versus angle" date="1446465524" name="Angle.png" path="Angle.png" size="34590" user="zxap013" version="2"
META FILEATTACHMENT attachment="Hot.png" attr="h" comment="dark frame 2s 5 deg" date="1446429347" name="Hot.png" path="Hot.png" size="36913" user="zxap013" version="1"
META FILEATTACHMENT attachment="g.png" attr="h" comment="3 second dark frame" date="1446430040" name="g.png" path="g.png" size="37628" user="zxap013" version="1"
META FILEATTACHMENT attachment="Background_hot.png" attr="h" comment="" date="1446590629" name="Background_hot.png" path="Background_hot.png" size="58066" user="zxap044" version="1"
META FILEATTACHMENT attachment="Background_nohot.png" attr="h" comment="" date="1446590629" name="Background_nohot.png" path="Background_nohot.png" size="113898" user="zxap044" version="1"
META FILEATTACHMENT attachment="Angle_fit.png" attr="h" comment="" date="1446592760" name="Angle_fit.png" path="Angle_fit.png" size="58841" user="zxap044" version="1"
META FILEATTACHMENT attachment="Focus_fit.png" attr="h" comment="" date="1446592759" name="Focus_fit.png" path="Focus_fit.png" size="61666" user="zxap044" version="1"
META FILEATTACHMENT attachment="latexd9ffb6fa7a3af9b5c4a1740e4aa755b7.png" attr="h" comment="" date="1446593566" name="latexd9ffb6fa7a3af9b5c4a1740e4aa755b7.png" user="zxap044" version="1"

Revision 202 Nov 2015 - AshleaKemp

Line: 1 to 1
 
META TOPICPARENT name="StewartBoogertSpectroscopy2015"
Hot Pixels
Line: 25 to 25
 -- AshleaKemp - 02 Nov 2015

META FILEATTACHMENT attachment="Hotpixels.png" attr="" comment="Dark frame spectrum" date="1446428380" name="Hotpixels.png" path="Hotpixels.png" size="34303" user="zxap013" version="1"
Changed:
<
<
META FILEATTACHMENT attachment="Focus.png" attr="" comment="Stdev against focus distance" date="1446428870" name="Focus.png" path="Focus.png" size="38219" user="zxap013" version="1"
META FILEATTACHMENT attachment="Angle.png" attr="" comment="stdev against camera angle" date="1446428896" name="Angle.png" path="Angle.png" size="37679" user="zxap013" version="1"
>
>
META FILEATTACHMENT attachment="Focus.png" attr="" comment="stdev versus focus" date="1446465546" name="Focus.png" path="Focus.png" size="32705" user="zxap013" version="2"
META FILEATTACHMENT attachment="Angle.png" attr="" comment="stdev versus angle" date="1446465524" name="Angle.png" path="Angle.png" size="34590" user="zxap013" version="2"
 
META FILEATTACHMENT attachment="Hot.png" attr="" comment="dark frame 2s 5 deg" date="1446429347" name="Hot.png" path="Hot.png" size="36913" user="zxap013" version="1"
META FILEATTACHMENT attachment="g.png" attr="" comment="3 second dark frame" date="1446430040" name="g.png" path="g.png" size="37628" user="zxap013" version="1"

Revision 102 Nov 2015 - AshleaKemp

Line: 1 to 1
Added:
>
>
META TOPICPARENT name="StewartBoogertSpectroscopy2015"
Hot Pixels

  • Analysed a two dark frames to find locations of hot pixels. 1st Dark frame had a 1 second exposure time at a temperature of 20 degrees. 2nd Dark frame had a second exposure time at a temperature at 5 degrees.
  • As can be seen from both spectrums below, the 2nd dark frame has comparatively less background fluctuations due to the lower temperature.
  • A code was written to print the index of the pixel values which exceed the mean+standard deviation of the 1D array obtained from summing each column of pixels downwards. Pixel values exceeding this limit are considered signicantly above the background.
  • Spectrum of dark frame analysed with spikes indicating hot pixels:
Hotpixels.png

3 second dark frame

  • Pixel values exceeding this limit were located at pixel positions 90, 180, 222, 407, 490, 497, 617 along the x axis for the 1st dark frame.
  • Pixel values exceeding this limit were located at positions 90, 222, 407, 617 along x axis for 2nd dark frame - conclude these are hot pixels.
Finding the best focus distance/camera angle

  • After meeting on 28/10/15, decided to fit a hyperbole to the standard deviation against focus distance plot and a sine function to the standard deviation against camera angle plot - these fits were a much better fit than the parabolas.
  • Chi square value for focus = 0.00665
  • Chi square value for angle = 0.000382
  • Still need to adjust errors - will ask Prof Cowan in own time
Focus.png

Angle.png

-- AshleaKemp - 02 Nov 2015

META FILEATTACHMENT attachment="Hotpixels.png" attr="" comment="Dark frame spectrum" date="1446428380" name="Hotpixels.png" path="Hotpixels.png" size="34303" user="zxap013" version="1"
META FILEATTACHMENT attachment="Focus.png" attr="" comment="Stdev against focus distance" date="1446428870" name="Focus.png" path="Focus.png" size="38219" user="zxap013" version="1"
META FILEATTACHMENT attachment="Angle.png" attr="" comment="stdev against camera angle" date="1446428896" name="Angle.png" path="Angle.png" size="37679" user="zxap013" version="1"
META FILEATTACHMENT attachment="Hot.png" attr="" comment="dark frame 2s 5 deg" date="1446429347" name="Hot.png" path="Hot.png" size="36913" user="zxap013" version="1"
META FILEATTACHMENT attachment="g.png" attr="" comment="3 second dark frame" date="1446430040" name="g.png" path="g.png" size="37628" user="zxap013" version="1"
 
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