Manta G032 camera measurements

Overview

This page contains data from the demo I did in lecture on 9/22/2015 of the Manta G032 camera.

The point was to measure the gain $ g $, dark current $ I_d $, and read noise $ N_r $ of the Manta G032 cameras we use in lab.

Measurement procedure

• Light source directed at the camera so to produce a range of intensities
• 100 frame movie recorded at 20 FPS with an exposure of 150 μs.
• 100 frame dark movie recorded with identical settings.
• Variance of each pixel (noise squared) plotted versus average value (signal).

Calculations

The expression for the value read from pixel $ x,y $ during time interval $ t $ is:

$ P_{x,y}[t]=g \left(I_{x,y}[t]+R_{x,y}[t]+D_{x,y}(t)) \right) $,

where

• $ I_{x,y}[t] $ is the number of photoelectrons that are generated during interval $ t $,
• $ R_{x,y}[t] $ is the read noise during time interval $ t $,
• and $ D_{x,y}[t] is the number of dark current electrons generated during time interval <math>t $

The variance of this expression is equal to the noise squared. There are three terms in the equation, and the total variance is equal to the sum of the variances of the three term. $ I_{x,y} $ is Poisson distributed, so the variance is equal to the mean, $ \langle I_{x,y} \rangle $. The second term has a constant variance that is a property of the camera, $ N_r $. The third term is Poisson distributed, with an average value of $ I_d t $. This gives:

$ \left\langle\left(P_{x,y}-\overline{P_{x,y}}=g\left(\langle I_{x,y}+N_r^2\right)\right)\right\rangle $