[Bus Fans]

7. Backgroung radiation

[anthonys]

CCD...I guess.

[~X~]

Noise should be come from here
1. CCD
2. Electronic circuits (amplifiers, A/D converters)
3. HEAT makes things worries !!
4. Time of power on CCD (generate Heat)

reduce Noise
-1. CMOS circle design
-2. post-process Alogrithm in camera (CPU depend)
-3. Noise Reduction function (CPU depend)

observe Noise
S/N = signal to Noise level
bright area => strong signal => Seems less noise
dark / grey area => weak signal => look like much noise
and there is some diff noise :
"chroma noise" is much easier find => much disturb to your image

p.s."chroma noise": noise dots in different color (red&green dots usually)

[Philippe]

光源,一張高光相快門又快,iso又低,甚小會有noise.

[tam_dominic]

As far as I know :
2. CCD
3. Electronic circuits (amplifiers, A/D converters)

The signal from CCD is not enough for image processing.

It is therefore the signal need "Electronic circuits (amplifiers" to amplify.

During the amplify process both the real data and no use data are emplifed. Amplified 'no use data' become noise.

The smaller the CCD the more amplification is needed and the more noise there would be.

[man1492]

"What about if you have long exposure time, the material colors and light sources have changed over time, and that each pixel will have different changes, resulting in noise? "

It is time varying signal, not noise.

[呀超]

曝光不足 Noise 都好嚴重！