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Toolkit for testing CCD cameras – one of tools Pi of the Sky project Wilga 2005 1 / 27 Toolkit for testing CCD cameras Janusz Użycki Faculty of Physics.

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Presentation on theme: "Toolkit for testing CCD cameras – one of tools Pi of the Sky project Wilga 2005 1 / 27 Toolkit for testing CCD cameras Janusz Użycki Faculty of Physics."— Presentation transcript:

1 Toolkit for testing CCD cameras – one of tools Pi of the Sky project Wilga / 27 Toolkit for testing CCD cameras Janusz Użycki Faculty of Physics Warsaw University of Technology

2 Toolkit for testing CCD cameras – one of tools Pi of the Sky project Wilga / 27 CCD matrix (Charge-Coupled Devices) CCD sensors are produced in full choice of resolution and dimenstions. They are accessible with diameter bigger than half inch. It is very important in professional astronomy applications. The CCD sensors are low noise and have high sensivity. selected resolution: 2048 x 2048 pixels, 15 x 15 m each

3 Toolkit for testing CCD cameras – one of tools Pi of the Sky project Wilga / 27 How it works main idea of readout from CCD sensor charges vs light making a photo exposure time photons empty

4 Toolkit for testing CCD cameras – one of tools Pi of the Sky project Wilga / 27 How it works horizontal shift of charges

5 Toolkit for testing CCD cameras – one of tools Pi of the Sky project Wilga / 27 How it works vertical shift of charges in a queue

6 Toolkit for testing CCD cameras – one of tools Pi of the Sky project Wilga / 27 How it works ADC amplifier video signal readout horizontal shift

7 Toolkit for testing CCD cameras – one of tools Pi of the Sky project Wilga / 27 How it works p n SiO 2 cross-section

8 Toolkit for testing CCD cameras – one of tools Pi of the Sky project Wilga / 27 How it works Inserting a charge into the CCD matrix p n the charge inserting egde barier

9 Toolkit for testing CCD cameras – one of tools Pi of the Sky project Wilga / 27 How it works Potential well confinement

10 Toolkit for testing CCD cameras – one of tools Pi of the Sky project Wilga / 27 How it works three phases clock signals

11 Toolkit for testing CCD cameras – one of tools Pi of the Sky project Wilga / 27 How it works three stages of charge moving process

12 Toolkit for testing CCD cameras – one of tools Pi of the Sky project Wilga / 27 Consequence of usage the CCD We had to use own Problems - the CCD matrix - control circuits - video signal amplifier - analog to digital converter (ADC) - noise, temperature of an environment, dark current, hot pixels, sensivity gradient - to find the best timmings - noise, gain selection - digitalization effects: offset, non-linearity etc.

13 Toolkit for testing CCD cameras – one of tools Pi of the Sky project Wilga / 27 Solutions - cold environment (about -10 C) - noise and infra-red radiation reduction - statistical methods for analizing black / dark photos – finding the best parameters Example: CCDamplifierADC lightreadout What is a total gain of the circuit?

14 Toolkit for testing CCD cameras – one of tools Pi of the Sky project Wilga / 27 Requirements for the toolkit for testing CCD cameras - designed for PC platform: Windows XP and 2000 systems (main platform for electronics) Linux system possible It was used ROOT library package and Microsoft Visual C++.

15 Toolkit for testing CCD cameras – one of tools Pi of the Sky project Wilga / 27 Requirements – continuation (1) - read images in fits astronomical format which is used by our aparature (there are raw data from the CCD)

16 Toolkit for testing CCD cameras – one of tools Pi of the Sky project Wilga / 27 Requirements – continuation (2) - eliminate the offset and hot pixels by substraction of two successive images

17 Toolkit for testing CCD cameras – one of tools Pi of the Sky project Wilga / 27 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 Toolkit for testing CCD cameras – one of tools Pi of the Sky project Wilga / 27 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 Toolkit for testing CCD cameras – one of tools Pi of the Sky project Wilga / 27 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 Toolkit for testing CCD cameras – one of tools Pi of the Sky project Wilga / 27 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 Toolkit for testing CCD cameras – one of tools Pi of the Sky project Wilga / 27 CCD Toolkit in action examples of print-screens main window (management)

22 Toolkit for testing CCD cameras – one of tools Pi of the Sky project Wilga / 27 CCD Toolkit in action preview window (enlargement)

23 Toolkit for testing CCD cameras – one of tools Pi of the Sky project Wilga / 27 CCD Toolkit in action histograms for XY & profiles

24 Toolkit for testing CCD cameras – one of tools Pi of the Sky project Wilga / 27 CCD Toolkit in action profiles (projections)

25 Toolkit for testing CCD cameras – one of tools Pi of the Sky project Wilga / 27 CCD Toolkit in action after division into regions

26 Toolkit for testing CCD cameras – one of tools Pi of the Sky project Wilga / 27 CCD Toolkit in action mean sigma example of bad gain fitting reason: offset

27 Toolkit for testing CCD cameras – one of tools Pi of the Sky project Wilga / 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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