|
|
Blooming
|
|
A pixel on a digital camera
sensor
collects photons which are converted into an electrical charge by
its photodiode. As explained in the dynamic range topic, once the
"bucket" is full, the charge caused by additional photons will
overflow and have no effect on the pixel value, resulting in a
clipped or overexposed pixel value. Blooming occurs when this charge
flows over to surrounding pixels, brightening or overexposing them
in the process. In the example below, the charge overflow of the
overexposed pixels in the sky causes the dark pixels at the edges of
the leaves and branches to be brightened and overexposed as well. As
a result detail is lost.
Blooming can also increase the visibility of
purple fringing.
|
| |
 |
| |
|
Some sensors come with
"anti-blooming gates" which drain away the overflowing charge so it
does not affect the surrounding pixels, except for extreme exposures
(very bright edge against a virtually black edge).
|
|
