How to identify noise in a captured image?

How the noises are measured.FPN is the component of pattern noise measured in the absence of illumination. ie means every dark image will have FPN am i correct.

Answer 1

[Image Analyst]

In your case there are two noises: fixed pattern noise, and dark noise.

For fixed pattern noise, you remove the lens from the camera and hit the sensor with uniform illumination. Make sure the signal does not saturate. The image you get is the fixed pattern noise.

To determine dark noise, you cover the sensor by taping over the hole or putting the lens cap on and turning the room lights off. The image you get is the dark noise. You may also see fixed pattern noise in the image if the fixed pattern noise is pretty bad (like a dead pixel that is always lit up to 255 or something).

[Anitha Thomas]

Thank you for your answer.

I want to identify the noise for the real time image.

I want to estimate the noise by using MATLAB.

How the noises are measured.FPN is the component of pattern noise measured in the absence of illumination. ie means every dark image will have FPN am i correct. ?