Help required regarding frame capture from video

[Burke46]

I am an engineer and know very little about cameras so I was hoping someone could enlighten me. I am studying the flow of a liquid and I want to record it and break the video down into it's sperate frames so the flow can be examined frame by frame.

I know I need a progressive frame rate to avoid bluring in the individual frames. I have tried using the 1080p camera on my phone, which I am assuming is a 30p camera, however the frames of a moving object are still very blur.

As I don't have any other camera I was wondering will this happen with any comercial camera or is it just the poor quality camera on my phone?

If this will happen to any comercial camera can anyone suggestion a solution

Thanks for the help

Burke46

 

[KmH]

Be careful about assuming.

You need a frame rate that is faster than the flow of the liquid.

What is the frame rate of your unidentified phone camera?W

What is the flow speed of the liquid?

Is the flow of the liquid laminar or turbulent?

 

[Burke46]

The camera on the phone records at 1080p at 30 fps
The flow is a wave followed and preceded by a turbulent flow
The speed is unknown and that is the purpose of the test
When you say "You need a frame rate that is faster than the flow of the liquid" what do you mean by this exactly.

Thanks for the help

 

[KmH]

Each frame is a shutter release, or a still image. The length of time the shutter is open determines if motion can or cannot be stopped during each exposure.

If the subject moves while while each still image exposure is made, the resulting image will have recorded motion blur.

You may need to use high speed strobe lighting. The short duration of the flash of strobed light then stops the motion, so you likely need more than 30 fps. Way more.

Harold Edgerton pioneered high speed strobe lighting - Harold Eugene Edgerton - Wikipedia, the free encyclopedia.

Here is 6000 fps.............

 

[Burke46]

Thanks for all your help KmH. I just have one last question. In your opinion for a high speed recording what level of blur would be acceptable in the measuring of the flow?

Thanks

 

[KmH]

What property(s) of the flow are you wanting to measure ?

 

[Burke46]

The fluid will be sloshing around in varying angle a tank 1 meter long. The test is being carried out to examine the flow inside the tank so very few properties are known. I am assuming that the velocity will be no more than 7 m/s.

I have done some calculations on a frame rate, taking a camera with a sensor width of 15.36 mm, a frame of focus of 2 m and object velocity as 7 m/s. I am getting a reduced velocity of 0.05376 m/s.

Through research i have found two sources which give to different acceptable level of blur

1) twice the size of a pixel => acceptable blur for a 1280 pixel camera works out to be 0.000012 m
and a frame rate = 320 fps

2) a acceptable level of blur is 0.0508 mm which gives a frame rate of 152 fps

Which would you suggest to be correct

Thanks

 

[KmH]

I can't venture a guess beyond that I think the frames rates you quoted, 320 fps/152 fps, won't come anywhere close to getting you any usable data.

Figure you're going to have to set up some gear, do some testing, and then do some refinement to get usable results.

At least now you know your phone camera isn't going to cut it.

 

[Burke46]

Sorry there was an error in my calculations. the frame rates for the option are
1) 4,480 fps
2)1028 fps
The first one seems a bit high but is the second on too small