 BetterPhoto Member |
Digital Noise I am interested in understanding the cause of seemingly random light spots in some pixels when taking digital pictures in very low light. I have a very superficial understanding that when the scene is very dark, the pixels get "confused" and some will register different colors and/or light. I would be interested in a better explanation. The spots are most visible when a dark picture is adjusted in Photoshop.
|
|
|
|
||
|
Alan N. Marcus |
The term noise in a digital image is a throwback term associated with audio systems. In radio and audio recordings, static, hiss, or other background sounds were referred to as noise. Noise, therefore is any random variation in the detection and reproduction of sound or images. The term noise was applied early on in photography when image flaws arose in telephone line transmittal associated with wire photos (early method of sending images over phone lines). Thus noise in photographic images is analogous to granularity (grain) which plagues the conventional silver based (film) imaging system. In digital chip recording systems, light is converted to an electrical charge. Always present is the undesirable presence of noise. Noise is triumphed when the light levels (scene brightness) is high. Higher light levels yield a strong signal with low noise known in engineering circles as high signal-to-noise-ratio. Whereas, low light levels have a low signal-to-noise-ratio. Noise in digital imaging is also analogous to optical flare which is often devastating. Future camera designs will incorporate lower noise electronics. Alan Marcus
|
|
|
|
||
|
This old forum is now archived. Use improved Forum here
Report this Thread |
||