Rolling Shutter - Basler A400K User Manual

Basic Operation and Features

3.4 Rolling Shutter

A rolling shutter is used to control the start and stop of exposure. A rolling shutter requires less in-
pixel transistors than a nonrolling shutter. This allows a larger photosensitive area per pixel, that
is, a higher fill factor and thus, a higher sensitivity.
The rolling shutter resets, exposes and reads out the pixel lines with a temporal offset of 4.56 µs
from one line to the next.
When exposure is triggered, the rolling shutter first resets the top line of pixels, then the second
line, then the third line, and so on. The reset progresses down the image from one line to the next
until the bottom line of pixels is reached (see Figure 3-8).
The time interval between a pixel line being reset and the pixel line being read out is the exposure
time. Exposure time is the same for all lines and determined by the exposure time setting. Due to
the pixel lines being reset and read out with an offset of 4.56 µs, the start of exposure has an offset
of 4.56 µs from one line to next.
The sequence of pixel readout is timed identically to the reset, starting from the top line and
moving down the image until readout of the bottom line is complete.
Reset
(Start of Exposure)
Column 1
Line 1
4.56 µs
Reset
Runtime
Figure 3-8: Rolling Shutter
3-8
DRAFT
Exposure Time
Line 1726
Readout
(End of Exposure)
Column 2352
Total Runtime
Readout
Runtime
4.56 µs
Basler A400k