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5 Functionality
5.1.6 Maximal Frame Rate
The maximal frame rate of the camera depends on the camera settings. The following factors
influence the maximal frame rate (see also Table 5.1):
•
The length of the exposure time: A shorter exposure time can lead to an increase in the
maximal frame rate.
•
ROI height: a smaller height ROI can lead to an increase in the maximal frame rate.
•
The exposure mode: Time controlled or trigger controlled
Depending on the timing situation the frame rate is calculated according to the formula in
Section 5.1.6or Section 5.1.6. In order to find out what is dominant, both situations need to be
calculated and the lower value defines the maximum frame rate.
This value can be also determined by a frame rate calculator in the support section of the
Photonfocus web page www.photonfocus.com. The maximal frame rate with the current
camera settings can be read out by a camera property AcquisitionFrameRateMax.
Readout dominated timing
The exposure time is smaller than the read out time in this timing (see Fig. 5.12). Exposure is
started during the sensor read out of the previous frame.
The maximal frame rate is in this case:
MaxFrameRate = (GigE Datarate)/(Width*Height*Bits per Pixel)
The number of bits per Pixel depends on the data output mode. Mono8 has 8 bit per Pixel,
Mono10Packed and Mono12Packed have 12 bit per Pixel.
The exact frame rate can vary with different camera settings.
6 r i g g e r
E x p o s u r e
R e a d o u t
Figure 5.12: Simultaneous read out timing 1: exposure time smaller than read out time. Not shown:
TExpDel
Exposure dominated timing
The exposure time is bigger than the read out time in this timing (see Fig. 5.13). Exposure is
started during the sensor read out of the previous frame.
The maximal frame rate is in this case:
MaxFrameRate = 1 / (ExposureTime + TReadoutDel)
TReadoutDel is fixed and lasts for 2.5 s. It is the time between the end of exposure and start
of readout.
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