Gain
Introduction
Gain is a parameter that lets the user configure the pre-amplification of the read-out circuit in the imaging sensor pixels. In photography, it is commonly referred to as ISO. Increasing the gain increases the pre-amplification of the sensor which will increase its sensitivity to light and thus result in brighter images.
Using Gain
The gain is beneficial for getting images of very dark regions if minimal time penalty is desired. However, high gain has a considerable drawback in the sense that it amplifies everything that the sensor measures. This includes noise, which makes 2D images appear grainy. It is therefore recommended to keep gain low, if optimal, low-noise 2D images are desired.
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Single acquisition capture with gain 1 |
Single acquisition capture with gain 16 |
Warning
Higher gain values create grainy 2D images.
Sometimes it is ok to get grainy 2D images. Consider a scenario with a strict time budget, and dark objects. In order to extract information from dark regions with low time penalty, gain is a good parameter to utilize.
Note
Gain can be an effective tool to extract data from very dark regions in the scene.
The table below shows how the available gain in Zivid 3D cameras relates to stops.
Gain |
1x |
2x |
4x |
8x |
16x |
Stops |
0 |
+1 |
+2 |
+3 |
+4 |
dB |
-6 |
0 |
6 |
12 |
18 |
The image below illustrates the impacts of gain on the dynamic range of the frame. The blue line illustrates the measured signal with gain=1 and the black line shows the same measured signal with gain=2.
The image below illustrates the measured signal level versus light intensity.
