X Y Speed detection

OpenMV related project discussion.
riodda
Posts: 3
Joined: Sat Nov 11, 2017 2:46 am

X Y Speed detection

Postby riodda » Sat Nov 11, 2017 2:52 am

Hi all, i came accross open mvcam while doing some research for an optical flow sensor.
I would like to develop an XY speed sensor for high performance vechiles (like correvit datron on a budget) and i would like to know if the mv cam will suit the task, i need to know expecially how to understand if with the appropriate lens i can detect up to high speed ( i guess i need to know the max frame rate).
For first the Y/X speed ratio detetection will be enough but i need very high speed (up to 250 km/h).
I think i can put the camera no more than 30-40 cm from the ground.
Many thanks for any help !
riodda
Posts: 3
Joined: Sat Nov 11, 2017 2:46 am

Re: X Y Speed detection

Postby riodda » Sat Nov 11, 2017 4:18 am

I had a quick look to the specs and as far as i have understood i should be able to get maximum 120 fps from the sensor, and considering 50% overlap between the frames, 120° fov lens and 40cm from the ground i should have a max speed of detection of 86 m/s that is more than enough therfore i would like to know if:

1. Is it plausible to get 120 fps out from the

Code: Select all

 [delta_x, delta_y, response] = old.find_displacement(img)
function considering even a 32X32 resolution ?
2. Is it the tarmac grain the right surface to evalute displacement ?

As anoter option i was thinking about taking "long" exposure picture in this way the grain will be blurred lines and use the line or segments angle functions but i haven't found how to control exposure and sensitivity.

Many thanks for guidance.
User avatar
kwagyeman
Posts: 2202
Joined: Sun May 24, 2015 2:10 pm

Re: X Y Speed detection

Postby kwagyeman » Sat Nov 11, 2017 10:38 am

Hi, with the M7 processor you might be able to get about 56 FPS using find_displacement with a 32x32 image. The kind of application you are trying to do seems like something you'd need a really high end camera for. Can you describe your setup for the camera better?
Nyamekye,
riodda
Posts: 3
Joined: Sat Nov 11, 2017 2:46 am

Re: X Y Speed detection

Postby riodda » Wed Nov 15, 2017 2:47 am

Thanks kwagyeman for you answer, i will try to explain better what i would like to do:
The holygrail of the vehicle dynamics if the evaluation of the Beta angle (or setup angle) that gives you a direct measuremente of the amount of understeer or oversteer that the car is having during a corder.
Do do so you can do an indirect meaurement with an IMU and a GPS or you can make a direct measurement with radar o optical XY speed sensors, this is he sensor that is a de facto standard in the automotive
http://www.dynatech-jp.com/product/CORR ... -350_e.pdf

This thing is extremely expensive and i was thinking if with the OpenMV cam is possible to develop something simila at a fraction of the cost, with a 56 fps what is the minimum overlap between the frames i need to have a accurate measurement ? Is it the asphalt grain suitable for such measurement ?

Return to “Project Discussion”

Who is online

Users browsing this forum: No registered users and 5 guests