PS3 Eye frame rate
wongfeirang from Malaysia  [26 posts]
6 years
Hi. I had used PS3 Eye for RR application. When I not RUN the RR program, the camera frame rate becomes 60Fps. However, when I run it with only single line of program (Mean Filter), it frame rate becomes half of actual frame rate (29Fps). I had tested it with another window machine with higher processor but the same problem happened. How this behavior happened and how to solve it?
Steven from United States  [1425 posts] 6 years
Any module requires CPU time ... the more CPU time (ie the more complex a module) the slower the effective fps will be. The system will snap a picture, process the image using all modules in sequence and then snap the next picture. Thus the effective fps will get slower as you add more modules. It just takes time to process images.

Hopefully this helps explain why things slow down!

Note, you will have experienced this before when running many applications on your PC ... it slows down right? Well, each module can be thought of as another application which also requires CPU processing.

wongfeirang from Malaysia  [26 posts] 6 years
I understand your explanation but when I am using the built in webcam on the Lenovo PC, the frame rate maintained at 30fps during Stop and Running the RR module. How this small webcam capable to maintain the frame rate that is not able on PS3 Eye?
Steven from United States  [1425 posts] 6 years
Again, its not the camera. Most likely you are running at a lower resolution on the built in webcam or something about the image is different enough to allow the modules to run faster. The issue with speed comparisons is that the modules must process exactly the same image from each camera in order to determine a correct fps. Image content WILL change processing time.

You can also post your robofile here if you'd like us to have a look at it and perhaps why you are getting such different times. If you can save an image from the PS3 and one from the webcam we can better tell you why you are getting different times.

Note that the PS3 is capable of running at 60fps while most webcams will only get 30fps so the hardware capability will dictate that when running on the same pipeline the PS3 will perform better than your webcam given the same image size.

wongfeirang from Malaysia  [26 posts] 6 years
I have attached the RR program file and sample image. The following are the setting frame rate result that appeared on Camera:

1. PS3 Eye

Resolution : 640 X 480 @ 75fps
Stop Module Frame Rate : 75fps
Run Module Frame Rate  : 27fps

2. Lenovo USB 2.0 UVC Camera (Built in on Lenovo PC)

Resolution : 640 X 480 @ 30fps
Color Space : YUY2
Stop Module Frame Rate : 30fps
Run Module Frame Rate  : 29fps


Steven from United States  [1425 posts] 6 years
On just about any machine the fps can easily slip between 27 and 29 depending on what other applications are active. Running the above on the static image at a max of 200fps I also get between 27 and 29 fps depending on what the machine is doing elsewhere.

To really prove this, start disabling the modules starting from the first and compare the speed between the two cameras. You will see the PS3 creep above 30 whereas the webcam will remain at or below 30.

Its just a question on how many modules you are using ... you have enough to reduce the speed from 75fps down to below 30.

An alternative is to reduce the resolution to 320x240 which will easily show the PS3 above 30 fps too. That's the easiest way to reduce CPU load.


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