Xovis Ag

Markus Herrli

David Studer

Martin Wuethrich

Christian Studer

Benjamin Raphael Miesch

Adrian Pauli

Martin Wüthrich

The invention relates to a method and an arrangement for determining a group of persons to be considered staying in an observation region by considering exception markings for other persons, wherein the group of persons to be considered is a group of the persons staying in the observation region excluding the other persons who stay in the observation region and carry one of the exception markings. Thereby, the exception markings are graphic pattern with at least one characteristic length ratio. At least one image is recorded of the observation region, and in the at least one image, the persons staying in the observation region and optical signatures of the exception markings are detected, wherein the detected optical signatures are assigned to detected persons. Furthermore, a detected group of the detected persons to be considered in the observation region is determined excluding the detected persons with assigned detected optical signature.

Method and arrangement for determining a group of persons to be considered

In a method for calibration of a stereo camera () comprising two cameras () arranged in a distance along a first direction (x) and mechanically attached to a common structure, rectification functions mapping raw image coordinates to rectified coordinates are provided. Recalibration is based on images of a scene captured by the stereo camera () affixed in an observation position, the recalibration yielding correction functions mapping rectified coordinates to corrected coordinates. Recalibration is based on matching objects comprised in images of the captured scene obtained by the two cameras (). The stereo camera () is affixed in a fixed relationship with a planar surface (), with a known distance and angle between the stereo camera () and the surface (), and objects are matched in the recalibration that belong to the surface (), wherein a disparity caused by the known distance is exploited when determining the correction functions. Exploiting the additional information with respect to the surface (), the determination of the correction functions may be greatly improved. In particular, the inventive method allows for employing general correction functions, and no modelling of the calibration errors is required.

Method for calibration of a stereo camera

Method for determining the length of a queue of objects in a predefined region having at least one entrance and at least one exit, in the course of which errors in the acquisition of objects entering or exiting the region are corrected during the determination of the length of the queue. In a first step, a specific entry signature E of each object entering the predefined region through the at least one entrance is determined with the aid of at least one first image sensor. Thereafter, the specific entry signature E is stored in an entry list of a calculation unit, each entry signature E being provided with an index value i reflecting the temporal sequence of the entries. In addition, a value L reflecting the length of the queue of the objects is increased by one. Furthermore, a specific exit signature A of an object exiting the predefined region through the at least one exit is determined with the aid of at least one second image sensor, the specific exit signature A being stored in an exit list of a calculation unit as exit signature Awith index value j=0. The index value of exit signatures Aalready present in the exit list is respectively increased by one, and exit signatures Awhich have an index value j that is greater than a predeterminable value M are deleted from the exit list. Subsequently, similarity values Cfor &#x2212;N&#x2266;n&#x2266;+N are calculated with the aid of the calculation unit, N being a predeterminable value which defines a specific number N of entry signatures of objects which, before or after the object with the entry signature Ewhich next exits the predefined region on the basis of the length of the queue L, will exit or have already exited the predefined region. In the process, similarity metrics Uare respectively calculated between an exit signature Aand an entry signature E, M running from 0 to M, and added to C. The value L is decremented by the value one. Subsequently, the similarity values Care compared with the similarity value C. The value L is corrected by adding the index value x given the presence of a value Cwith index value n=x that indicates a higher similarity than the similarity value C.

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Allmendingen, Switzerland

Markus Herrli