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Toolkit for testing CCD cameras

Toolkit for testing CCD cameras. Janusz Użycki Faculty of Physics Warsaw University of Technology. CCD matrix (Charge-Coupled Devices). CCD sensors are produced in full choice

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Toolkit for testing CCD cameras

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  1. Toolkit for testing CCD cameras Janusz Użycki Faculty of Physics Warsaw University of Technology

  2. CCD matrix(Charge-Coupled Devices) CCD sensors are produced in full choice of resolution and dimenstions. They areaccessible with diameter biggerthan half inch.It is very important in professionalastronomyapplications. The CCD sensors are low noiseand have high sensivity. selected resolution: 2048x2048 pixels, 15x15m each

  3. How it worksmain idea of readoutfrom CCD sensor making a photo exposure time photons charges vs light empty

  4. How it works horizontal shift of charges

  5. How it works vertical shiftof chargesin a queue

  6. How it works video signal ADC horizontal shift amplifier readout

  7. How it works f3 f2 f1 n SiO2 p cross-section

  8. How it works f3 f2 f1 p n Inserting a charge into the CCD matrix the charge inserting egde barier

  9. How it works Potential well confinement

  10. How it works three phases clock signals

  11. How it works three stagesof chargemovingprocess

  12. Consequence of usage the CCD

  13. Solutions - cold environment (about -10C) - noise and infra-red radiation reduction - statistical methods for analizing „black / dark photos” – finding the best parameters Example: CCD amplifier ADC light readout What is a total gain of the circuit?

  14. Requirements for the toolkitfor testing CCD cameras • designed for PC platform: • Windows XP and 2000 systems • (main platform for electronics) • Linux system possible • It was used ROOT library packageand Microsoft Visual C++.

  15. Requirements – continuation (1) • read images in fits • astronomical format which is used • by our aparature • (there are raw data from the CCD)

  16. Requirements – continuation (2) • eliminate the offset and ‘hot’ pixels • by substraction of two successive images

  17. Requirements – continuation (3) • display pictures • the preview allows to find • main errors instantly • cut egdes for analize to find • the best useful part of view

  18. Requirements – continuation (4) • XY histogram single pixel distribution • it allows to find min/max brightness of view • X and Y profile (sum or average) to find unvisible errors, dark current effect for example

  19. Requirements – continuation (5) • X and Y profile (projection) histograms • divide the image into regions and make single pixel histograms, fit Gauss distribution parameters (mean and sigma values) We can estimate where is a bad region.

  20. Requirements – continuation (6) • plot chart in mean and sigma axis to fit gain line and pitch of one (tangens of angle)Here is an answer for question:What is a total gain of the circuit? • electrons / ADU value = pitch of the line

  21. CCD Toolkitin actionexamples of print-screens main window (management)

  22. CCD Toolkitin action previewwindow (enlargement)

  23. CCD Toolkitin action histograms for XY& profiles

  24. CCD Toolkitin action profiles (projections)

  25. CCD Toolkitin action afterdivision into regions

  26. CCD Toolkitin action exampleof badgain fittingreason: offset sigma mean

  27. Summary • program is still testing and it will be developing and improving • if necessary- there is a lot of work for tuning the best parameters for our new cameras

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