I heard about a technique calculating the angles between two vectors;
say the object moves from point A to B, C and D. You calculate the
vectors AB, BC, CD, and then the angles between them; if it is a
straight line, the angles should be 180°. You could display all angles
in a histogram to draw conclusions. Maybe someone more into that kind of
analysis can comment on the usefulness of that?
More sophisticated are other approaches;
http://www.mosaic.ethz.ch/Downloads/ParticleTrackerCSourceAndClientIt is based on the moments of displacements from where you calculate MSS
slopes (moment scaling spectrum) and their values give you an idea about
the type of motion; bulletin-like (i.e. straight line) or confined
random brownian motion; have a look at the publication!
Johannes
Am 28.04.2011 18:18, schrieb Gluender:
> Dear Rodrigo,
>
> if it's really only "degree/amount of deviations from a straight
> line", i.e. if direction of the movement is unimportant, hence loops
> or circles need not recognized as such, then why not use linear
> regression of the points and specify the deviations by one of the
> common measures for the fit, such as R^2 ?
>
>> Dear ImageJ users,
>>
>> I analyzed a trajectory of a single moving object, extracted its
>> position at each slice, and now I have a list of (X,Y) points (which
>> is the integrated trajectory of the object in a given time).
>>
>> Are you aware of any tool to analyze (quantify) the degree of
>> tortuosity of this trajectory?
>>
>> The tortuosity would be some estimation of the degree/amount of
>> deviations from a straight line, a way of quantifying if the
>> trajectory is closer to a straight line or if it's full of twists and
>> curves. A first approach would to calculate the ratio of the actual
>> path length to the euclidean distance between start and endpoint.
>>
>> This may sound easy (like just dividing the accumulated traveled
>> distance by the distance between the 1st and last points), but there
>> are several ways to do it (for example how to consider a circle?):
>>
http://en.wikipedia.org/wiki/Tortuosity>>
>> I am looking for a general mechanism, which eventually I could use
>> for a 3D space (i.e., pool of points X,Y,Z).
>>
>> Any info will be welcome!
>> Respectfully,
>> Rodrigo
>>
>> ________________________
>> Rodrigo J. Gonçalves
>> ________________________
>
> Best
>
> Herbie
>
> ------------------------
> <
http://www.gluender.de>
>