What is blooming in CCD?
What is blooming in CCD?
Blooming occurs when the charge in a pixel exceeds the saturation level and the charge starts to fill adjacent pixels. Typically CCD sensors are designed to allow easy vertical shifting of the charge, but potential barriers are created to reduce flow into horizontal pixels.
What is CCD imaging?
A charge-coupled device (CCD) is an integrated circuit containing an array of linked, or coupled, capacitors. CCD sensors are a major technology used in digital imaging. In a CCD image sensor, pixels are represented by p-doped metal–oxide–semiconductor (MOS) capacitors.
Who invented the CCD?
Willard Boyle
The charge coupled device (CCD), invented by Willard Boyle and George Smith in 1969, became one of the most prolific imaging sensors.
What is CCD saturation?
Saturation and blooming are related phenomena that occur in all charge-coupled device (CCD) image sensors under conditions in which either the finite charge capacity of individual photodiodes, or the maximum charge transfer capacity of the CCD, is reached.
What is a CCD used for?
Charge coupled devices, or CCDs, are sensitive detectors of photons that can be used in telescopes instead of film or photographic plates to produce images. CCDs were invented in the late 1960s and are now used in digital cameras, photocopiers and many other devices.
What is the function of CCD?
In plain English, CCD devices convert or manipulate an electrical signal into some kind of output, including digital values. In cameras, CCD enables them to take in visual information and convert it into an image or video. They are, in other words, digital cameras.
When does blooming occur in a CCD sensor?
Blooming occurs when the charge in a pixel exceeds the saturation level and the charge starts to fill adjacent pixels. Typically CCD sensors are designed to allow easy vertical shifting of the charge but potential barriers are created to reduce flow into horizontal pixels.
When does blooming of a CCD become a nuisance?
Blooming can be a nuisance when a strong signal can obscure data from a weak signal of interest especially on an image with a high dynamic range. Blooming is usually less of an issue in spectroscopy applications when the CCD is aligned to be in the same orientation as the spectrograph slit.
Why does a CCD have a vertical streak?
Typically CCD sensors are designed to allow easy vertical shifting of the charge, but potential barriers are created to reduce flow into horizontal pixels. Hence the excess charge will preferentially flow into the nearest vertical neighbours. Blooming therefore produces a characteristic vertical streak, e.g. see the image below right.
How to minimize the effects of blooming in charge coupled devices?
Although a variety of different mechanisms are available to minimize the effects of blooming in charge-coupled devices, depending on the specific CCD design and type of application, it is usually preferable to recognize and avoid saturation conditions rather than to rely on antiblooming measures.