USB Transfer failed causing latency

[larsjacquemetton]

We've been using this code for a sensor triggered USB IDS camera. It works well some of the time but randomly we get a USB transfer error which reads 'WARNING:ids:USB transfer failed (1 instance) with the number of instances, which can range from 1 to 10, basically being the latency in increments of ~ half a second before we can get a photo from the camera.

Unfortunately getting the timing of the photo correct is pretty important to this application. If anyone has any incite into how to help resolve this and get this working for USB ids please let me know.

[prattmic]

Unfortunately I have never used this module to control a USB camera, so I cannot provide a lot of insight.

If your application is sensitive only to capture timing, not receipt, you may be able to work around the issue by looking at the 'timestamp' element in the info dict returned by the next() method. This timestamp has the capture time, as reported by IDS' is_GetImageInfo() function. It was never clear to me whether that timestamp indicates the true time of capture or the time the uEye libraries received the image, but it may help.

[rhasqx]

The timestamp reported by is_GetImageInfo() depends... trigger mode or freerun, rolling/global shutter, etc.

[sur83]

I tryed to run it under virtualbox in linux, Ubuntu (host windows), and I have the same error. This error occur always and i am not able to capture any image, never. However, I can import the camera, set the exposure, etc correctly. The problem is when using: img,meta=cam.next()
Did you solve it? Can you share the solution, please?

[untaut]

For me the USB transfer failures stopped after I lowered pixel_clock from the default of 24 to 20. Your mileage may vary. A count of failures is displayed at the bottom of the main window in the ueyedemo program, and you can move the settings slider until they stop increasing.