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>

>