[android-developers] Re: Is it possible to reduce the variability of camera shutter lag time?

Thanks for the suggestions. Based on them I tried disabling all the camera auto parameters. There is still a range of about 0.2 s in the shutter lag time. In this application (and perhaps there are others), I'm more concerned about the variability and not the average duration of the lag time. I have posted a feature request to the Android issue tracker to add an optional minimum shutter time argument in Camera.takePicture() that would delay the shutter if it were ready before the specified minimum. If you think you might find that extra control helpful in a future application, "star" the feature request at http://code.google.com/p/android/issues/detail?id=35785

Thanks! --Greg

P.S., We have the same initials, and for a while a few years ago I used those same initials as an on-line signature. Our writing styles are similar enough that I sometimes read your posts and momentarily wonder, "Did I write that?" :*)

On Monday, July 30, 2012 9:02:37 PM UTC-4, gjs wrote:

Hi,

Set other camera parameter values to non-auto settings eg: set a specific white balance such as daylight, set flash to off etc.

Other than that ensure there is no other non essential app's / services running at the same time & examine your own app to minimise or eliminate any garbage collection, reduce sensor use / frequency.

Try a few different devices, dual cores, quad cores particularly those claiming zero shutter lag. Some devices let you vary the camera preview frame rate & preview size maybe try this as well, not sure if that would make a difference as I've have not tried this myself.

If that is still not good enough consider triggering a remote camera instead, such as an SLR via bluetooth or usb.

Regards 

On Tuesday, July 31, 2012 6:41:53 AM UTC+10, greg wrote:

Thanks Richard. Setting the focus to Camera.Parameters.FOCUS_MODE_INFINITY helped as shown in the added histogram at http://stackoverflow.com/questions/11727240/how-to-reduce-the-variability-in-android-camera-shutter-lag

At the risk of sounding like an ingrate, do you have any ideas on how to reduce the variability even more? (A range of 0.2 s still covers a large portion of the periodic motion.)

-- Greg

On Monday, July 30, 2012 3:05:50 PM UTC-4, RichardC wrote:

Could it be related to auto-focus? Try turning it off.

On Monday, July 30, 2012 7:55:52 PM UTC+1, greg wrote:

Given a known periodic motion (e.g., walking), I'd like to take a full resolution snapshot at the same point in the motion (i.e., the same time offset within different periods). However on the Nexus S (currently running OS 4.1.1 but the same was true of previous OS versions), I'm seeing so much variability in the shutter lag that I cannot accurately plan the timing of the snapshot. Is there anything I can do in the application to reduce this shutter lag variability? (In this application, the mean lag can be any duration but the standard deviation must be small ... much smaller than the 0.5 s standard deviation I am seeing.) I'm hoping someone has a clever suggestion. If I don't get any suggestions, I'll post a feature request in the Android bug tracker.

I've posted the same question (and showing a histogram of camera shutter lag times) at

http://stackoverflow.com/questions/11727240/how-to-reduce-the-variability-in-android-camera-shutter-lag

Thanks! -- Greg

--
You received this message because you are subscribed to the Google
Groups "Android Developers" group.
To post to this group, send email to android-developers@googlegroups.com
To unsubscribe from this group, send email to
android-developers+unsubscribe@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/android-developers?hl=en