Unsure behavior between exposure and fps for short exposure

rentogen

I am using the asi290.

After reviewing the SDK documentation and manual, I still couldn't quite understand the relationship between the set exposure and the observed fps, for example when the exposure is very short.

Example: exposure is set to 12500us. Expected fps is 80fps, but observed fps under some conditions is actually 25fps. The number of dropped frames is increasing, but not at 80fps. So the question is, are the frames that are actually captured exposed for 12500us or 40000us?

That is, are the pixels actually being reset at 80fps (every 12500us), but some of the frames are not being captured? Or is the driver lagging, and the frames are actually being exposed at 25fps (every 40000us)?

chad

Hi Sir,

The actual frame rate is influenced by many factors.

In general, not only exposure time, but also sensor speed and usb bandwidth.

For example：

A sensor‘s max framerate is 60fps in full size. And the full size is 15M.

If you set the exposure time to 0s, However you still can not get 60fps. Because 15M*60=900M, it is out of the USB bandwidth. For USB3.0, it 's max bandwidth is about 400M, so it should be 400/15=26fps.

If you set a ROI, and the size is 1M, exposure time is 0s, if then sensor only support 150fps, then you can not get the 400fps, it should be 150fps.

If you set a ROI, and the size is 1M, sensor support 150fps, however, the exposure time is 50ms, now the framerate is 1000/50=20fps.

di it solve your problem?

Thanks

Chad