Measuring of Cameras Parameters

As special service EURECA offers the measuring of special cameras parameters, in order to determine the most important specifications of such systems. This is possible both for single pieces (e.g. for scientific projects) or for a new camera series of a manufacturer.

The measurements are made mainly based on the recording of photo transfer curves, from which all important characteristics of a camera system can be derived. Only with knowledge of these data cameras can be used senseful in highly exact scientific and industrial projects. Also a comparison of different camera models among themselves is only possible based on this data. The service is charged depending on the number of specifications to be measured and the requested form of the documentation for the measurement.

• Conversion rate
  This value determines the ratio of the signal voltage output to the electrons produced in a sensor pixel (and/or with digital cameras the relationship between LSB and electrons)
  
  
• Read out noise
  The output stages of an image sensor as well as the readout electronics are sources of noise. This noise depends very strongly on the used readout speed. It is particularly important for applications, with which only very little light is available, in order to optimize the signal-to-noise ratio.
  
  
• Dark current
  The dark current results from the accumulation of thermal electrons in the photodiode of the sensor. It is dependent on the temperature and disturbs the sensor signal at longer exposure times.
  
  
• Full well capacity
  This value tells how many electrons an individual pixel can collect before it runs into the saturation. So this is an important parameter to specify at which quantity of light a camera is oversaturated and then a correct measurement is no longer possible.
  
  
• Linearity
  Double quantity of light means not always also a double output signal. This effect is called non-linearity. If the linearity of a system is well-known, this effect can be compensated by additional software corrections.
  
  
• Fixed Pattern Noise
  Separate pixel have usually different values for offset and senitivity. With CMOS image sensors this effect is more strongly pronounced than with sensors on CCD basis.
  
  
• Quantum efficiency
  This value indicates how many of the incoming light quanta are converted into electrons by the pixel of the sensor. This is particularly of interest for low light applications.
  
  
  
  

Last updated: 4/11/2008