Franciscus C A Groen

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The estimation of protein secondary structure from circular dichroism spectra is described by a multivariate linear model with noise (Gauss-Markoff model). With this formalism the adequacy of the linear model is investigated, paying special attention to the estimation of the error in the secondary structure estimates. It is shown that the linear model is(More)
  • P Van Der Smagt, F Groen, F Van Het Groenewoud
  • 1994
| We present a method for accurate representation of high-dimensional unknown functions from random samples drawn from its input space. The method builds representations of the function by recursively splitting the input space in smaller subspaces, while in each of these subspaces a linear approximation is computed. The representations of the function at(More)
– In this paper a stereovision method is described developed for autonomous vehicle navigation in unstructured terrain. The disparity between the stereo image sequences is calculated with sub-pixel accuracy. Robust distance values are obtained by adding a continuity criterion term in the evaluation criterion and by using confidence measures for the found(More)
A pilot study is described on the practical application of artiicial neural networks. The limit cycle of the attitude control of a satellite is selected as the test case. One of the sources of the limit cycle is a position dependent error in the observed attitude. A Reinforcement Learning method is selected, which is able to adapt a controller such that a(More)
The control of lightweight compliant robot arms is cumbersome due to the fact that their Coriolis forces are large, and the forces exerted by the relatively weak actuators may change in time as the result of external (e.g. temperature) influences. We describe and analyse the behaviour of a lightweight robot arm, the SoftArm robot. It is found that the(More)
– In this paper we present an algorithm for tracking vehicles through an image sequence. The algorithm is based on matching a model in the image plane to each observed vehicle. The model is based on the characteristic edges of an intensity image of a vehicle. This model is applied to track vehicles through image sequences. We introduce three refinements to(More)
An ADS (Automatic Debiting System) is an electronic fee collection (EFC) system on a freeway, which interacts with a transponder in each car, and subtracts a fee from a credit card. Non-payers are to be photographed and ned. In requirements on such systems in The Netherlands, privacy laws demand separation between the nancial transaction and the(More)
Shadow detection is an important aspect of foreground/background classification. Many techniques exist, most of them assuming that only the intensity changes under shadow. In this paper we show that in most practical indoor and outdoor situations there will also be a color shift. We propose an algorithm for estimating this color shift from the images, and(More)