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jianshi
May 18, 2015, 16:04:05
Hi,

My question is concerning the time after calling LiveStart() until the image is stabilized. I am using USB camera DMK 72AUC02, with IC Imaging Control 3.2 and driver usbcam_2.7.9_tis.

When I modify camera settings with different ROI and frame rate, I use code similar to below:
class ContainerWindow
{
TIS.Imaging.ICImagingControl imagingControl;
ContainerWindow()
{
//initialize imagingControl
}

void ChangeSettings()
{
imagingControl.LiveStop();
modifySettings();
imagingControl.LiveStart();
}
}

The execution of ChangeSettings() typically takes less than 1 second, but the control takes a lot longer to generate a stable image. The behavior is that imagingControl first becomes black, then the camera image shows up and gradually stabilizes after several seconds.

My product manager is complaining about the time too long for camera to stabilize. While I understand the instrument needs time to generate a stable image, I would like to understand the expected time from the manufacturers point of view.

Is there a rule of thumb that gives the stabilization time based on the ROI size, frame rate and other settings?

Thank you very much for your kind attention!

-Jian

Stefan Geissler
May 18, 2015, 17:08:08
If the camera runs on automatics for gain, exposure and white balance, then a few frames are needed for self adjusting.
Also the image settings are valid after a frame has been delivered.
The process is faster the higher the frame rate is. If you use a low frame rate, e.g. 2 fps, then you need 5 seconds for 10 frames. If you have a small ROI and high frame rate, then this is much faster.

jianshi
May 19, 2015, 13:36:36
If the camera runs on automatics for gain, exposure and white balance, then a few frames are needed for self adjusting.
Also the image settings are valid after a frame has been delivered.
The process is faster the higher the frame rate is. If you use a low frame rate, e.g. 2 fps, then you need 5 seconds for 10 frames. If you have a small ROI and high frame rate, then this is much faster.

Hi Stefan,

For the setting that behaves slow, the settings are:

Frame rate 3
Rotation 0
FlipHorizontal TRUE
FlipVertical FALSE
Auto Exposure FALSE
Auto Gain FALSE
Filter FALSE

The gain / exposure / white balance are not dynamically adjusted.

The timing from LiveStop() to getting a stable image displayed takes approx. 2 seconds. The break down is 0.6 sec to execute code, 1.4 sec to get back a stable image.

Another thing I noticed is that if the ROI is slightly smaller than the full view, the execution time is actually longer (2.3 seconds).

Could you please give some suggestions on how to tweak the camera settings to get back image sooner? Is the current timing reasonable?

Thanks,
-Jian

Stefan Geissler
May 19, 2015, 15:10:50
Hi Jian

what do you mean by "stable image"?

jianshi
May 19, 2015, 16:54:24
Hi Jian

what do you mean by "stable image"?

The ICImagingControl was initially showing all black right after calling LiveStart(). Then the actual image shows up and "stays".
The "stable image" was meant that this actual image being displayed.

Thanks,
-Jian

Stefan Geissler
May 20, 2015, 10:00:31
I see.

If the control becomes black, then you got a black image, because the background of the control is white. After the first image, the camera properties must be effective in the sensor, so the second image should be brighter.

I do not understand, what
FILTER False

should be.

Which computer model do yo use?

Stefan Geissler
May 20, 2015, 10:00:31
I see.

If the control becomes black, then you got a black image, because the background of the control is white. After the first image, the camera properties must be effective in the sensor, so the second image should be brighter.

I do not understand, what
FILTER False

should be.

Which computer model do yo use?

jianshi
May 21, 2015, 04:54:22
I see.

If the control becomes black, then you got a black image, because the background of the control is white. After the first image, the camera properties must be effective in the sensor, so the second image should be brighter.

I do not understand, what
FILTER False

should be.

Which computer model do yo use?

Hi Stefan,

I captured a video to show you the transition timing. Please see attached zip file.
One picture is worth a thousand words, hope the video explains my concern for the slow refresh after calling LiveStart().

This video is captured when switching the camera setting between two settings

The one with slower transition is 3 FPS (the one with bright dot in the center)
The one with faster transition is 40 FPS

My concern is why the 3 FPS transition takes about 1 second to change from black to actual image.
My understanding so far is that the 1st frame is black, the second frame is a valid image. The transition time
should be 1/3 second (based on 3 frame per second).

Computer OS is Windows 7 64bit.

Thanks,
-Jian

jianshi
May 26, 2015, 15:13:24
Hi Stefan,

I captured a video to show you the transition timing. Please see attached zip file.
One picture is worth a thousand words, hope the video explains my concern for the slow refresh after calling LiveStart().

This video is captured when switching the camera setting between two settings

The one with slower transition is 3 FPS (the one with bright dot in the center)
The one with faster transition is 40 FPS

My concern is why the 3 FPS transition takes about 1 second to change from black to actual image.
My understanding so far is that the 1st frame is black, the second frame is a valid image. The transition time
should be 1/3 second (based on 3 frame per second).

Computer OS is Windows 7 64bit.

Thanks,
-Jian

Hi Stefan,

I apologize for persisting on this transition timing question, my goal is to understand if the instrument behavior is as expected or if there is any action I can take to make the transition faster.

Do you have any suggestions / comments on the behavior captured in the video? Many thanks for your help!

Regards,
-Jian