Hot pixel removal

  • Median filter test on the Cd spectrum image at 1.50mm with size=4:
    Cd_1.50_median_filter_size4.png
  • Top images are pre filter, bottom are post filter.
  • Spectrums are the number of photoelectrons as a function of the pixel position
  • Adjusting the size to 1 yields no removal, size = 2 gives mediocre removal and increasing the size past 4 gives no further improvement.

  • Median blur test on the Cd spectrum image at 1.50mm with ksize=3:
    Cd_1.50_medianBlur_size3.png
  • Adjusting the ksize to 1 yields no removal and increasing the ksize past 3 gives no further improvement.

  • Both scipy.ndimage.filters.median_filter and cv2.medianBlur remove hot pixels from this test image with mostly the same result.

  • Median filter test on the 20s dark frame with median_filter size 4:
    DarkFrame_20s_1_median_filter_size4.png

  • Median blur test on the 20s dark frame with ksize=3:
    DarkFrame_20s_1_medianBlur_size3.png

  • Reducing the size and ksize below 4 and 3 respectively yields minimal noise reduction.
  • If removing the hot pixels from the spectrum images works, is processing the dark frames a requirement?

  • Median filter test on the Cd spectrum image at 6.50mm with size 4:
    Cd_6.50_median_filter_size4.png

  • Median blur test on the Cd spectrum image at 6.50mm with ksize=3:
    Cd_6.50_medianBlur_size3.png

  • Testing code on a much brighter section of the spectrum (6.50mm) also shows hot pixel reduction

-- WillBurrows - 13 Oct 2016

Plots and trying to smooth out the curve

  • This Figure shows the plot of the pixal value against the number of photoelectrons, the plots on the top are with the original values, the plots on the bottom are where the average is taken for the 10 adjacent values.
  • Plot for cadmium calibration for grating of 0mm:
    Cad_plt_0.00.png

  • Plot for cadmium calibration for grating of 6.5mm:
    Cad_plt_6.50.png

  • Plot for cadmium calibration for grating of 10.0mm:
    Cad_plt_10.0.png

  • Plot for cadmium calibration with the shutters closed:
    Cad_plt_darkframe.png
Topic attachments
I Attachment History Action Size Date Who Comment
PNGpng Cad_plt_0.00.png r1 manage 127.9 K 13 Oct 2016 - 22:23 JamesAngthopo Plot for cadmium calibration for grating of 0mm
PNGpng Cad_plt_10.0.png r1 manage 129.9 K 13 Oct 2016 - 22:30 JamesAngthopo Plot for cadmium calibration for grating of 10.0mm
PNGpng Cad_plt_6.50.png r1 manage 53.9 K 13 Oct 2016 - 22:29 JamesAngthopo Plot for cadmium calibration for grating of 6.5mm
PNGpng Cad_plt_darkframe.png r1 manage 121.2 K 13 Oct 2016 - 22:30 JamesAngthopo Plot for cadmium calibration with the shutters closed
PNGpng Cd_1.50_medianBlur_size3.png r1 manage 110.2 K 13 Oct 2016 - 17:49 WilliamBurrows Median blur test on the Cd spectrum image at 1.50mm with ksize=3
PNGpng Cd_1.50_median_filter_size4.png r1 manage 106.6 K 13 Oct 2016 - 17:48 WilliamBurrows Median filter test on the Cd spectrum image at 1.50mm with size=4
PNGpng Cd_6.50_medianBlur_size3.png r1 manage 61.3 K 13 Oct 2016 - 18:06 WilliamBurrows Median blur test on the Cd spectrum image at 6.50mm with ksize=3
PNGpng Cd_6.50_median_filter_size4.png r1 manage 61.1 K 13 Oct 2016 - 18:05 WilliamBurrows Median filter test on the Cd spectrum image at 6.50mm with median_filter size 4
PNGpng DarkFrame_20s_1_medianBlur_size3.png r1 manage 126.3 K 13 Oct 2016 - 17:52 WilliamBurrows Median blur test on the 20s dark frame with ksize=3
PNGpng DarkFrame_20s_1_median_filter_size4.png r1 manage 127.8 K 13 Oct 2016 - 17:52 WilliamBurrows Median filter test on the 20s Dark frame with median_filter size 4
Texttxt hot_pixel.py.txt r1 manage 1.4 K 13 Oct 2016 - 18:12 WilliamBurrows Hot pixel removal test code - python - 20161013
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Topic revision: r2 - 13 Oct 2016 - JamesAngthopo

 
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