Charge Coupled Devices and Optics - Experiment | ECE 437 | Lab Reports Electrical and Electronics Engineering

ECE 437 LABORATORY #5 Fall 2007

CHARGE COUPLED DEVICES (CCDs) AND OPTICS

Goals:

The goal of this laboratory is to familiarize you with a CCD camera, operated as a single frame

device as a remote sensing tool.

Learning Objectives: After completing this laboratory, you should be able to:

1. Explain the operating principles, advantages, and disadvantages of CCD sensors.

2. Determine the critical issues for sensor implementation through laboratory investigation of

simple image collection and analysis.

Laboratory Preparation: In preparation for this laboratory, you should:

1. Attend the lecture and read the materials on the Apogee CCD University website at

http://www.ccd.com/ccdu.html. Look at the Finger Lakes camera spec sheet at

http://www.fli-cam.com/FLIproducts/ME2.htm.

PQ1: List 2 specific applications that would call for CCD cameras as sensors.

PQ2: What kind of accuracy is necessary in each application? Compare the two relative

accuracy levels in your analysis.

PQ3: What kind of support electronics, including information storage, are needed to

implement the CCD sensor in each application?

Laboratory Tasks and Questions:

The following instructions will allow you to operate the Finger Lakes CCD camera for this lab.

The CCDs are sensitive devices – please familiarize yourself with the startup and shutdown

procedures prior to continuing with the lab.

Power On Procedure

1. The cameras should already be running. If not, plug them in. Make sure that the cooling fan

is running. If not, consult your TA.

2. Log on to the computer.

3. Start the MaxIm software and go to View→CCD Control Window. You can alternatively

open this window by clicking on the appropriate tab in the toolbar. Under the Settings tab,

verify that both X Binning and Y Binning are set to 1 before proceeding with the lab. The

TA can show you where this is.

4. Click Setup and be sure that the main camera is set up to be the Finger Lakes CCD.

5. Click Connect. You should now be ready to go.

Power Off Procedure

1. Leave the camera on. If the cooling is on, click Warm Up in Setup of the CCD Control

Window and wait for the camera to come to roughly room temperature.

2. Set the CCD to Cooling Off.

3. Disconnect the camera from the CCD control window (NOT THE COMPUTER).

4. Shut down the MaxIm software.

5. Log yourself off of the computer

6. Leave the camera on.

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CHARGE COUPLED DEVICES (CCDs) AND OPTICS Goals: The goal of this laboratory is to familiarize you with a CCD camera, operated as a single frame device as a remote sensing tool. Learning Objectives: After completing this laboratory, you should be able to:

Explain the operating principles, advantages, and disadvantages of CCD sensors.
Determine the critical issues for sensor implementation through laboratory investigation of simple image collection and analysis. Laboratory Preparation: In preparation for this laboratory, you should:
Attend the lecture and read the materials on the Apogee CCD University website at http://www.ccd.com/ccdu.html. Look at the Finger Lakes camera spec sheet at http://www.fli-cam.com/FLIproducts/ME2.htm. PQ1 : List 2 specific applications that would call for CCD cameras as sensors. PQ2 : What kind of accuracy is necessary in each application? Compare the two relative accuracy levels in your analysis. PQ3 : What kind of support electronics, including information storage, are needed to implement the CCD sensor in each application? Laboratory Tasks and Questions: The following instructions will allow you to operate the Finger Lakes CCD camera for this lab. The CCDs are sensitive devices – please familiarize yourself with the startup and shutdown procedures prior to continuing with the lab. Power On Procedure
The cameras should already be running. If not, plug them in. Make sure that the cooling fan is running. If not, consult your TA.
Log on to the computer.
Start the MaxIm software and go to View→CCD Control Window. You can alternatively open this window by clicking on the appropriate tab in the toolbar. Under the Settings tab, verify that both X Binning and Y Binning are set to 1 before proceeding with the lab. The TA can show you where this is.
Click Setup and be sure that the main camera is set up to be the Finger Lakes CCD.
Click Connect. You should now be ready to go. Power Off Procedure
Leave the camera on. If the cooling is on, click Warm Up in Setup of the CCD Control Window and wait for the camera to come to roughly room temperature.
Set the CCD to Cooling Off.
Disconnect the camera from the CCD control window ( NOT THE COMPUTER ).
Shut down the MaxIm software.
Log yourself off of the computer
Leave the camera on.

CHARGE COUPLED DEVICES (CCDs) AND OPTICS Introduction – The Camera and Software We will use this part of the lab to introduce ourselves to the CCD camera and MaxIm software. The camera should already be powered on and the TE cooling system, complete with fans, should be running. The camera will have its cooling system off, so that the CCD temperature will be roughly room temperature. Please become familiar with the location of the camera, its components, and the optical rail that it is sitting on. The TA will give a brief presentation introducing the camera and the software. If you have any questions regarding the camera or software that are not addressed in this presentation, please consult the CCD tutorial or the supplemental material presented in class and on the web. CCD Noise Background: Two sources of noise dominate the CCD camera background. First, refer to the data sheet to obtain the camera gain in units of volts per electron. Amplifier noise from this source is termed ' noise floor ' on the CCD data sheet. The other is ‘ dark signal ’ due to thermal noise generation. We will investigate these sources of noise and try to understand their relative behavior.

Set the camera up for a dark current exposure in the “Expose” subheading of the CCD Control Window. Go to the CCD Control Window, Settings sub-window, and set both the X and Y Binning to 1. Set the exposure time to 0.02 s (this is the minimum exposure time due to the finite shutter speed), and take an exposure. Keep the camera at room temperature (i.e. you should have the ‘dark’ option selected).
You should observe that one side of the image is dark, while it gets increasingly noisy (whiter) as you move towards the other. Q1: Explain why the dark image has the above characteristic. Hint: Think about how the camera moves charge through the 2-dimensional array.
Zoom in to 1600% magnification and locate a position on the camera with noise. Open the information window by clicking View→Information. Change the mode of this window to Area.
Using the cursor, highlight a square box containing 100 pixels. The number of pixels highlighted is displayed in the information box. Record the standard deviation and average of the noise signal for later use. Q2: Briefly describe the meaning of the maximum and minimum value.
Repeat for exposure times of 0.05, 0.5, 1.5, 2.5, 3.5 and 5 seconds. Keep your 100 pixel box in the same location for every trial.

CHARGE COUPLED DEVICES (CCDs) AND OPTICS Chip Binning Background: Chip binning is a way to combine two or more pixels in the x and/or y axes to create 'superpixels.' We will use this section to get an introduction to this feature.

Take a non-saturating image of the room.
Now, go to the CCD Control Window, Settings sub-window, and set the X and Y Binning both to 2 and redo the exposure. Repeat for 4 and 8. Q8: What happens to the width and height of your image? Why?
Now set the Y Binning back to 1 and the X Binning to 8. Q9: Explain what happens to your image. Q10: Explain chip binning in your own words. CCD Blooming Background: When driven beyond saturation, electrons from full wells will migrate to neighboring, ‘less full’ wells. We will carefully investigate this phenomenon. The white light source gets very hot when it is on for a while, so be careful not to burn yourself.
Set up the fiber-coupled white light source as shown above. If you have questions about the fiber connections, consult your TA.
Now, turn off all the room lights. If there are monitors on, turn them away from the cameras. We are trying to create a single point source for our CCD.
Take an exposure at 0.02 seconds. Using the Information box, make sure that you are not saturated. Using the screen stretch function, and zooming in to 1600%, analyze the image of the output of the optical fiber. You may see two spots. Q11: Try to explain the origin of the second spot if you only have one fiber aperture. Even if you do not notice a second spot, think of why this might occur.

CHARGE COUPLED DEVICES (CCDs) AND OPTICS

Increase the exposure time slowly (500 ms at a time) until you begin to observe blooming. Do not expose longer than 5 seconds. Q12: Explain what you see when blooming occurs. In other words, how does the image change when you approach 5 seconds? Describe how the pixels saturate and the 'migration' of saturation. Is there a preferred direction of migration? Imaging Background: We will now use the camera to perform simple imaging experiments.
Place a ruler roughly 1 meter from the camera. Use the focus procedure to take continuous images from the CCD (be sure that the focus feature is set to ‘continuous’). You still have to manually focus the lens (use the focus lens). You can do this at any zoom level you find appropriate. Increasing the binning factor at the beginning will speed up the readout process so you can get an initial focus. However, to get the final focus, you will want to use a binning factor of 1.
Using the 1600% zoom feature, determine the magnification of your camera with the ruler at its present position. This measurement should be done by counting pixels (9 microns by 9 microns) within an imaged distance on the ruler, such as 1 centimeter or more. Using the imaging equation, verify this measurement. Q13: Determine the angular resolution of your camera in units of degrees per pixel. Q14: Determine the spatial resolution of your camera at the location of the ruler. Q15: Repeat Q13 for the ruler at 2 meters. Q16: Repeat Q14 for the ruler at 2 meters. Q17: What is the resolution of your camera when imaging the moon? Hint: You will need to look up some numbers for this calculation. Student Post-Lab Questions and Conclusions
Briefly explain the operation of the CCD camera in your own words. Include discussion of CCD operation theory.
What are the main advantages and disadvantages of the sensor? List at least two of each.
Discuss the noise limits of the sensor and how some of those may be overcome by system design
What are two important lessons that you learned from this lab that deal with the implementation of CCD sensors? Plots
- Plot of uncooled noise vs. exposure time
- Plot of cooled noise vs. exposure time

Charge Coupled Devices and Optics - Experiment | ECE 437, Lab Reports of Electrical and Electronics Engineering

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