from the vehicle dynamics or the surrounding and use
them for the prediction of the prospective motion. Ex-
amples for those concepts are (Gindele et al., 2013)
or (Tang et al., 2015). The prediction task in well
structured environments is not easy, but it is unlikely
harder in unstructured environments without lanes,
lane markers or any traffic guidance. In this paper,
we understand wide places, pedestrian areas or park-
ing lots as unstructured environment, for example.
Or to define it in a general way: As unstructured
environment, we consider places where no clear de-
fined infrastructure guides the movement of the traffic
participants, or they are not known by the autonomous
system. Without this context knowledge, the calcula-
tion of various features gets impossible and some ma-
neuvers, like changing the lane, are getting invalid if
there is no lane anymore.
For those depicted problems in the field of mo-
tion prediction, we present an approach which uses
heuristics to find possible target points of traffic par-
ticipants and thus narrowing the solution space for
future motions. Subsequently, a discriminating deci-
sion process decides the most probable aim of the ob-
ject. With the inference of target points we are able to
predict possible future motions of traffic participants
(e.g. pedestrians), bypassing the lack of context infor-
mation.
2 PROPOSED APPROACH
In the proposed approach, we model the intention
recognition task as a goal-driven process and predict
the dynamic objects towards those goals. A pseudo
algorithm is given in Algorithm 1. Trying to reduce
the complexity of the intention recognition task, we
apply appropriate heuristics to find a rough estimation
of possible goals, called target points. This happens
in line two in Algorithm 1. Subsequently, we are cal-
culating, in line three to six, target point related fea-
tures for every point and evaluate with a classifier, if it
could be the true goal. In the next step, we choose the
most probable result of our classification step, which
is now regarded as the future goal of the considered
object. For unknown objects, an initialization step
is executed, where a first shortest path trajectory is
planned to the calculated aim and the covariance ma-
trix is initialized. In the following step, we predict
the object towards its most probable target point. The
prediction step itself is divided into several steps and
described in detail in 2.4.
The mentioned steps of the presented algorithm
are now described in detail.
Algorithm 1: Target point intention recognition algorithm.
1: for all Obj do
2: T P = updateTargetPoint()
3: for all T P do
4: Feat = calcTargetPointFeatures()
5: doIn f erence()
6: end for
7: t p
best
= chooseBestTargetPoint()
8: if Obj != known then
9: initPrediction()
10: end if
11: [Pos,CoVar] = predictOb ject()
12: end for
2.1 Target Point Generation
The purpose of the generation of target points is the
reduction of the possible goals of a regarded object
using heuristics. In Algorithm 1, this task is done in
line two. Without reduction, the amount of possible
goals is infinite and the calculation of the most prob-
able one impossible. For the true target of the traf-
fic participant to be in the domain of possible targets,
their number and distribution is crucial, otherwise the
predictions will be misleading and counterproductive.
Is the distribution of target points too dense, more op-
tions are matching with the true aim and the calcu-
lation process is getting very costly. Therefore, our
target points have different origins. As a conservative
safety measure, we search for possible target points
(safety points T P
Sa f
) of traffic participants that dan-
gerously interfere with the motion of the ego vehicle.
Further, we consider possible midterm goals of traffic
participants and place the target points (motion points
T P
Mot
) in such a way that a natural motion pattern is
enabled. The last source of target points is the usage
of special points of interest (T P
PoI
) like crosswalks,
pedestrian lights or bus stations. This leads to a de-
fined set of target points
T P
sum
= T P
Saf
+ T P
Mot
+ T P
PoI
(1)
Further, the heuristics for finding appropriate
target points are explained in detail.
2.1.1 Target Points from Safety Relevant Motion
Hypothesis
To ensure safety we have to look for target points of
traffic participants that would dangerously interfere
with the ego motion. So we generate a target point in
such a way, the regarded object has to cross the future
trajectory of the ego vehicle. If an object is already
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