Point Grey Flea3 USB 3.0 Technical Reference 8 Troubleshooting
8.6 Rolling Shutter Artifacts
The rolling shutter used on the CMOS sensor of the camera may produce undesirable effects under certain
conditions.
Skew—Skew occurs if the camera is panning horizontally while the sensor is still exposing making vertical objects
appear to be leaning. Skew can be minimized by slowing the pan or increasing the frame rate (or both).
Wobble—Wobble is a stretching of objects due to vibration or sudden motion of the camera or the object. Wobble
can be minimized by increasing the frame rate or slowing the shutter speed; however, the wobble effect is then
masked by motion blur.
Partial Exposure—Partial Exposure occurs when a sudden change of lighting, such as a flash, significantly alters the
exposure, but only for a portion of the frame. This results in dark and bright horizontal bands. Partial Exposure can be
minimized by synching the light source to the exposure.
Title Article
Key differences between rolling shutter and frame (global) shutter
Knowledge Base Article 115
Related Knowledge Base Articles
For models with a global reset sensor, rolling shutter distortion may be minimized by capturing images in Trigger
Mode 0 , Trigger Mode 1 or Trigger Mode 15 (only when number of acquired images = 1). In these modes, exposure is
controlled by the global reset feature of the sensor. In global reset mode, all of the pixels on the sensor begin
collecting charge simultaneously, rather than row by row. The end of integration, however, is still delayed on the
sensor row by row from top to bottom as readout takes place. One result of this behavior is a partial reduction in
motion blur and other effects typical of rolling shutters. Another less desirable effect may be a gradual increase in
brightness from top to bottom of an image.
Unlike standard rolling shutter behavior, using a strobe flash in global reset mode may further reduce image
distortion, and in dark conditions may even eliminate it.
Revised 9/27/2012
Copyright ©2011-2012 Point Grey Research Inc.
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