Estimation of vehicle speed

[a2moosh]

If for example two lines are defined with a distance of x meters from one to the other it would be great if there could be a speed estimation added to objects.

[vsaw]

You are right that should give you an approximate speed. However it is currently not part of OpenDataCam and would either have to be implemented (feel free to give it a go 🙂) or you will have to do the post-processing outside of OpenDataCam.

See also #254

[vsaw]

@tdurand Ive renamed to issue and will leave it open for people to see and measure interest. (I get the feeling it pops up every couple of months)

[haviduck]

well, i think this is doable with the current api. last time i played with odc i remember seeing drawable areas for counting. that plus counterhistory where you get entry and exit timestamps is enough along with a certainty of fps and knowing the realworld box distance.

from there on out its just math. but accurate estimations are really sketchy.. youd have to place your roi in a head on view. imagine doing this in a roundabout. youd have to calculate curvature etc.. that being said, api is enough unless i read the docs completely wrong here.

kinda like this (which is also a reasonable alternative to areas)
https://github.com/ronitsinha/speed-detector/blob/master/demo.gif

object enters view - > timestamp
object reaches line - > timestamp
pixels per meter = get to measuring

def estimateSpeed(location1, location2,ppm=8.8,fps=24):
	d_pixels = math.sqrt(math.pow(location2[0] - location1[0], 2) + 
			     math.pow(location2[1] - location1[1], 2))
	d_meters = d_pixels / ppm
	fps = 18
	speed = d_meters * fps * 3.6
	return speed

in javascript something like
function estimateSpeed(location1, location2,ppm=8.8,fps=24){ var d_pixels = Math.sqrt(Math.pow(location2[0] - location1[0], 2) + Math.pow(location2[1] - location1[1], 2)) var d_meters = d_pixels / ppm fps = 18 speed = d_meters * fps * 3.6 return speed