How Is a Dark Frame Taken in CCD Cameras?

In summary, the process of taking a dark frame image involves closing the shutter to capture the state of the pixel array. To determine camera efficiency as a function of energy, one can use a standard brightness source or a calibrated camera and also utilize techniques such as measuring gain and signal variance. An excellent resource for further information on CCDs is the review by MacKay in the Annual Review of Astronomy and Astrophysics.
  • #1
Pingona
2
0
Hello,

I have two question regarding CCD camera technology.

How is a dark frame(image) taken ? ( Is this simply the state of the pixel array when the shutter is in close position?

How can one determine the camera efficiency as a function of energy from energy dependent measurements? What data or parameters should I look into for this analysis.

Thank you
 
Engineering news on Phys.org
  • #2
Pingona said:
Hello,

I have two question regarding CCD camera technology.

How is a dark frame(image) taken ? ( Is this simply the state of the pixel array when the shutter is in close position?

How can one determine the camera efficiency as a function of energy from energy dependent measurements? What data or parameters should I look into for this analysis.

Thank you

What is the context of your question? Is this for research, or industrial application, or a school report? What reading have you done up to now, and can you point us to some of those information resources?
 
  • #3
Research work. I am reading the book by James Jainseck on CCD technology. what we have is images from a CCD camera
 
  • #4
Pingona said:
How is a dark frame(image) taken ? ( Is this simply the state of the pixel array when the shutter is in close position?
Yes, you generally want to take a dark with the same exposure as the real image.

How can one determine the camera efficiency as a function of energy from energy dependent measurements?
if you mean the Quantum Efficiency then you need a standard brightness source (or another calibrated camera to compare it against).
Charge transfer efficency you can do with an iron 55 source, the radiation creates a fixed number of electrons per event - you can then measure the measured signal in adjacent pixels.

You can also use the fe55 to measure the gain (numbers in your image compared to real electrons in the CCD) - there is also a signal variance technique you can do with real data

I don't know how easy it is to get online but there is an excellent review of CCDs in "MacKay, C.D. 1986, Annual Review Astronomy&Astrophysics 24, 255, “Charge-coupled devices in astronomy” it's a lot more readable than Janesick's book
 

Related to How Is a Dark Frame Taken in CCD Cameras?

1. What is a CCD camera?

A CCD (Charge-Coupled Device) camera is a type of electronic image sensor that converts light into electrical signals. It consists of an array of light-sensitive pixels that capture and store an image when exposed to light.

2. How does a CCD camera work?

A CCD camera works by using a process called photoelectric effect. When light hits the pixels on the CCD sensor, it creates an electrical charge proportional to the intensity of light. This charge is then converted into a digital signal and processed to create an image.

3. What are the advantages of using a CCD camera?

CCD cameras have several advantages, including high resolution, low noise, and high sensitivity to light. They also have a wide dynamic range, meaning they can capture both bright and dark areas in an image with detail. Additionally, CCD cameras have a global shutter, which allows them to capture fast-moving objects without distortion.

4. What are the applications of CCD cameras?

CCD cameras are commonly used in digital cameras, video cameras, and scientific imaging systems. They are also used in medical imaging, astronomy, and microscopy. CCD cameras are essential in capturing high-quality images for research, analysis, and documentation purposes.

5. What is the difference between CCD and CMOS cameras?

The main difference between CCD and CMOS cameras is the way they capture and process images. CCD cameras use a bucket-brigade method, where the charge is transferred across the entire sensor to be read out. CMOS cameras, on the other hand, use a different approach, where each pixel has its own amplifier and is read separately. This makes CMOS cameras faster, more power-efficient, and less expensive compared to CCD cameras.

Similar threads

Sensor "pixels" count vs digital image output pixels count
    • Electrical Engineering
Replies
8
Views
1K
I CCD Readout Noise vs Temperature
    • Astronomy and Astrophysics
Replies
11
Views
2K
B How often do you re-acquire dark and bias frames?
    • Astronomy and Astrophysics
Replies
1
Views
933
Using a CCD camera to solve physics problems
    • Introductory Physics Homework Help
Replies
3
Views
2K
ABC reference frame synchronous generator modelling in Ltspice
    • Electrical Engineering
Replies
1
Views
1K
A Determination of photoelectron counts from the ARPES signal
    • Atomic and Condensed Matter
Replies
1
Views
2K
I How to do the Dark Frame Subtraction? (camera imaging)
    • Other Physics Topics
Replies
16
Views
3K
B Infrared Detectors & The 2nd Law of Thermodynamics
    • Thermodynamics
5
Replies
152
Views
5K
Measuring Reflectance with a Digital Camera
    • Optics
Replies
9
Views
1K
Energy Collected in one pixel on a CCD.
    • Introductory Physics Homework Help
Replies
1
Views
1K

Hot Threads

Recent Insights

Back
Top