Dark noise refers to the statistical variation in the number of electrons thermally generated within a pixel of an image sensor. This happens independently of light (photons), meaning it's present even in complete darkness. It's essentially the electron equivalent of photon shot noise, which is noise caused by the statistical fluctuations in the number of photons hitting the sensor. Unlike other types of noise that can be minimized by subtracting background levels, dark noise is inherent to the sensor's physical properties and cannot be completely eliminated through background subtraction. This is because it is a statistical variation, not a consistent signal.
Several sources mention "Dark Noise" in a different context, referring to an app providing ambient sounds for sleep, focus, or relaxation. This application utilizes various ambient sounds like white noise, pink noise, or brown noise to achieve these purposes. This should not be confused with the definition of dark noise in image sensor technology.
Here's a breakdown of the two distinct meanings:
1. Dark Noise in Image Sensor Technology
- Definition: Random fluctuation in the number of electrons generated within a pixel due to thermal effects, even in the absence of light.
- Cause: Thermal energy causing electrons to be released within the sensor's pixels.
- Effect: Increases image noise, reducing image quality.
- Mitigation: Cooling the sensor can reduce dark noise, but it cannot be completely eliminated.
- Distinction from other noise: Unlike background noise, dark noise is inherent to the sensor and cannot be removed through background subtraction.
2. Dark Noise (App)
- Definition: A mobile application offering various ambient soundscapes to aid relaxation, sleep, and focus.
- Purpose: Provides users with a selection of background sounds, including (but not limited to) white noise and brown noise.
- Availability: Available on iOS devices (iPhone, iPad, Mac).
It's crucial to understand the context when encountering the term "Dark Noise" to avoid confusion between these distinct meanings. The original question, lacking context, could be interpreted in either way.
