Digital Shift - Smartek Vision Giganetix GC Series User Manual

4.3.4 Digital Shift

The DigitalShift property is part of the camera's analog controls and allows a data selection from the full bit
depth of the sensor (14 Bit) to 8 Bit. As shown in Figure 95, all cameras by default use the 8 Most Significant
Bits (MSB) of the 14 Bit Analog-to-Digital Converter (ADC) to create 8 Bit pixels, the Least Significant Bits
(LSB) are cut off.
The DigitalShift property of the camera allows to shift the selected bits into the direction of the LSBs. As
e.g. by default bits 6 to 13 are used, a DigitalShift value of 1 outputs bits 5 to 12 from the ADC. Table 51
shows the ADC bits outputted at each DigitalShift value.
Shifting the significant pixels to lowers has two main effects; similar to doubling the analog amplification of
the signal, the brightness in the image will double with each step. It thus enhances the maximum signal
raise possible by the analog gain. Further it makes the lower bits of the ADC accessible to detect very low
signals while transferring 8 bit pixels, without a further amplification of the signal.
Analog to Digital Converter
Output Bits (0 – 13)
Output Data (8Bit)
Shift by 1
Shift by 2
Figure 95: Digital Bit Shifting at Analog to Digital Converter
DigitalShift Value
0 (default)
1
2
3
4
5
6
Table 51: DigitalShift values and used ADC bits
Shift by 3
Bits at ADC
6 to 13
5 to 12
4 to 11
3 to 10
2 to 9
1 to 8
0 to 7
115
4 Image Acquisition
SMARTEK Vision Giganetix User Manual Version 2.1.4