Hi all, 

I worked on this project a while back - www.ben-dror.com/pinokio I want to 
get it running on a beagle bone. 
I have purchased a BBB and a ps3 eye. OpenCV face-tracking seems to run at 
a very low frame-rate. I guess I am looking for around 15fps.
Please any insights would be greatly appreciated. 

Adam


On Wednesday, February 19, 2014 9:03:43 AM UTC+13, Michael Darling wrote:
>
> Glad I could help.  =]   Let me know what you find out after looking into 
> it a little bit more!
>
>
> On Tue, Feb 18, 2014 at 11:31 AM, <[email protected] <javascript:>> wrote:
>
>> you are absolutely right. at 1280x720 it is limited to 10 fps in YUYV 
>> format and i do get about 26fps in 640x480, but that could be just how fps 
>> are calculated. so it could be 30 in reality. 
>>
>> thank you.
>>
>>
>> On Tuesday, February 18, 2014 2:12:16 PM UTC-5, Michael Darling wrote:
>>
>>> My first question for you would be which pixel format are you capturing 
>>> in?  If you do a "v4l2-ctl -d /dev/videoX --list-formats-ext" in the 
>>> command line (where X is 0, 1, ...  whatever your C920 is) you can see the 
>>> various pixel formats, resolutions, and frame rates supported by the camera.
>>>
>>> For YUYV, the maximum frame rate at 1280x720 is 10 fps.  If you are 
>>> using H.264 or MJPEG, the maximum frame rate is 30 fps.
>>>
>>> I'm doubtful that that's your problem since you are still only getting 
>>> 15 fps at lower resolutions.  (Can you get 30 fps at 640x480?  That is the 
>>> resolution I am using for my own project and might serve as a good baseline 
>>> measurement.)
>>>
>>> My only other thought for now is that your actual measurement of the 
>>> frame rate could be wrong.  I don't have much experience with pthreads, but 
>>> I know that some of the "clock" functions in the <ctime> header have to be 
>>> handled differently when you are multi-threading.
>>>
>>> Those are my only ideas for now.  I'll keep racking my brain and let you 
>>> know if I come up with something else.
>>>
>>> - Mike
>>>
>>>
>>>  On Sun, Feb 16, 2014 at 10:57 AM, <[email protected]> wrote:
>>>
>>>> Hello, ive been reading through the group and found i have found it 
>>>> very helpful. i am running an odroid u2 with ubuntu 12.11 and opencv 
>>>> 2.4.6.1.
>>>> i used the code i found in git 
>>>> :/mdarling39/<https://github.com/mdarling39/LinuxVision/blob/master/OCVCapture.cpp>to
>>>>  capture from a logitech c920. i ran into an issue when i set the 
>>>> resolution to 1280*720 the fps would not go past 10. however for any 
>>>> smaller resolution i am able to get 15 fps no problem. the custom capture 
>>>> code certainly does use less resources than the built in opencv function. 
>>>> i 
>>>> have 2 threads, the main for capturing and the second for processing both 
>>>> of which do not max out their cpu so i cant figure out why im getting this 
>>>> fps drop.
>>>>
>>>>
>>>> any help would be appreciated.
>>>>
>>>> Thanks
>>>>
>>>> On Thursday, January 30, 2014 3:17:40 PM UTC-5, Matthew Witherwax wrote:
>>>>
>>>>> If you bypass OpenCV and capture directly like we did, you should test 
>>>>> to see if you can capture successfully in YUYV format.  OpenCV can 
>>>>> convert 
>>>>> YUYV to a Mat with less than 3% cpu use.  If you capture in MJPEG, you 
>>>>> will 
>>>>> see cpu use of 90% or more to convert the image to a Mat.  This isn't so 
>>>>> bad on the Wandboard because it only consumes one core, but can be 
>>>>> intense 
>>>>> on the single core BBB.  I can tell you from testing with the Wandboard 
>>>>> Quad, it can push 30 fps in YUYV over USB.  However, it is only possible 
>>>>> to 
>>>>> stream from one camera at 30 fps in YUYV.  In short it is a tradeoff.  
>>>>> You 
>>>>> can either saturate the USB and save processing or save bandwidth and 
>>>>> increase processing. Something to consider depending on your needs.
>>>>>
>>>>>
>>>>> On Thu, Jan 30, 2014 at 12:53 PM, Michael Darling <[email protected]
>>>>> > wrote:
>>>>>
>>>>>> Okay, so the problem you're having has to do with bugs in OpenCV, 
>>>>>> itself.  Unfortunately, the capture methods in OpenCV do not set the 
>>>>>> camera 
>>>>>> properties correctly for video4linux devices.  In other words, you may 
>>>>>> write the line of code to set the frame rate to 30 fps, but the camera 
>>>>>> isn't actually getting the instruction to change the frame rate.
>>>>>>
>>>>>> The fix Matthew and I have used is to just use our own video4linux 
>>>>>> capture code.  You might be able to modify the OpenCV source code, but 
>>>>>> the 
>>>>>> capture code is difficult to follow since there are so many layers of 
>>>>>> abstraction. (There are a lot of wrapper classes used to handle v4l2 
>>>>>> devices, v4l1 devices, Mac, Windows so that the programmer doesn't have 
>>>>>> to 
>>>>>> handle each camera differently depending on his/her system.)
>>>>>>
>>>>>> Hope that explains some things for you  :)
>>>>>> - Mike
>>>>>>
>>>>>> -- 
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