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ADC - Bit readout explained


Readout from sCMOS (Scientific CMOS) sensors used in XIMEA cameras is a bit more complicated which is why this simple explanation can help understand the final speed (frames per second) and output:

Rolling shutter

Sensor readout 2 x 12 bit means one High gain (HG) and one Low gain (LG) channel.
That is how these sensors work.

Transport depends on the output_bit_depth parameter.
It can be set to 8, 10, 12, 16 which means 2x8, 2x10 and so on.

Image formats:
RAW8, RAW16 - data are merged from HG and LG.
RAW8x2, RAW16x2 - RAW data from the sensor. Both HG and LG data for each pixel are present.

Global shutter

Sensor readout 4 x 10 bit means again High gain and Low gain data, but for Signal image and Reset image each.

Transport depends on output_bit_depth parameter.
It can be set to 8, 10, 12, 16 which means 4x8, 4x10 and so on.

Image formats:
RAW8, RAW16 - data are merged from HG and LG.
RAW8x4, RAW16x4 - RAW data from sensor. Both HG and LG data for a pixel for Signal image and Reset image are present.

Calculator

To calculate the frame rate and other parameters you can use this helpful TOOL.
Fill inputs (the orange values) and see the expected results.
Each input is connected to a xiApi parameter - e.g. Transport bit depth field is XI_PRM_OUTPUT_DATA_BIT_DEPTH xiapi parameter
Because of the processes mentioned above, in this case, if you change the Transport Bit Depth from 8 to 10 the Frame rate is still the same for example.

Note: 1300 MB limit was introduced into the Calculator because not all computer configurations were able to support higher speed, but now certain PCs could reach stable 1750 MB.