Abstract: A method for classifying an object in image data to one out of a set of classes using a classifier, said image data comprising an image of the object, each class indicating a property common to a group of objects, the method comprising the steps of obtaining said classifier used to estimate for an input feature vector a probability for each of the set of classes, one probability indicating whether the input feature vector belongs to one class; extracting a feature vector from said image data; using the obtained classifier to estimate the probabilities for the extracted feature vector; and evaluating the estimated probabilities for determining whether the object does not belong to any one of the set of classes based using a quality indicator.

Abstract: A hand-held device for authenticating a marking on an object, said marking exhibiting a viewing-angle dependent light reflection spectrum. The device includes an imager for receiving light from said object and generating image data that include spectrum information, a marking detector for detecting marking image data associated with said marking in said image data, a parameter evaluator for determining a value of a predetermined spectrum parameter based on spectrum information of at least a part of said marking image data, an angle estimator for determining a value of a viewing angle between said imager and said marking associated with a determined value of said spectrum parameter, and an authenticator arranged for making an authentication decision based on at least two spectrum parameter values and their associated viewing angle values.

Abstract: A hand-held device is described for authenticating a marking on an object, said marking exhibiting a viewing-angle dependent light reflection spectrum, said device comprising: —an imager for receiving light from said object and generating image data that include spectrum information, —a marking detector for detecting marking image data associated with said marking in said image data, —a parameter evaluator for determining a value of a predetermined spectrum parameter based on spectrum information of at least a part of said marking image data, —an angle estimator for determining a value of a viewing angle between said imager and said marking associated with a determined value of said spectrum parameter, and—an authenticator arranged for making an authentication decision based on at least two spectrum parameter values and their associated viewing angle values.

Abstract: A method for classifying an object in image data to one out of a set of classes using a classifier, said image data comprising an image of the object, each class indicating a property common to a group of objects, the method comprising the steps of obtaining said classifier used to estimate for an input feature vector a probability for each of the set of classes, one probability indicating whether the input feature vector belongs to one class; extracting a feature vector from said image data; using the obtained classifier to estimate the probabilities for the extracted feature vector; and evaluating the estimated probabilities for determining whether the object does not belong to any one of the set of classes based using a quality indicator.