This paper describes a n approach t o the extraction of articulated objects which will be used f o r gait analysis. In most medical applications markers are used t o determine trajectories of different body parts. This approach works without any markers. Monotony operators which compute the displacement vector field are used t o initialize a contour based tracking algorithmcalled active rays -f o r several body parts which are important f o r gait analysis. T h e contours of differe n t parts of the h u m a n body are extracted and tracked. These parts are approached by simple 3 0 geometric objects (blocks), which 3 0 position and m o t i o n are estimated f o r the each image of the image sequence. Then, the trajectories of the moving parts represented b y the 3D blocks can be determined and used f o r classification of different gait disorders.

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An important aspect in machine strength grading of timber is the direction of the grain and deviations from the main axis, which can cause a dramatic loss of strength. Therefore, an essential requirement of the wood industry is to find the direction of wood fibres in a fast and noninvasive way. For three decades now the use of polarised microwave radiation has been investigated, revealing the main direction of wood fibres in a non-contact and non-destructive way. The development of new small sized patch antennas now allows the detection of grain deviations on a local scale using a free microwave transmission method. This paper presents experimental results on accuracy and resolution for spruce specimens of different dimensions. Local signal variations, as well as boundary effects are discussed, particularly in view of possible industrial implementation.

The possibility for pre-grading of logs throughout the year has been evaluated based on dynamic modulus of elasticity (MOEdyn or simplified Edyn) by means of frequency-based nondestructive testing (NDTfreq). The challenge is that Edyn is variable in the frozen, partly frozen, and unfrozen states of logs (state of matter). In the unfrozen state, NDTfreq is reliable if the moisture content does not fall below fiber saturation. The state of the matter was tested via temperature measurements of air and log by means of an infrared technique and sensors, and information was evaluated from NDTfreq. The temperature measurements proved to be inefficient for industrial application because of unreliable data and long measurement times, whereas the NDTfreq measurements allowed the determination of meaningful damping factors. A sufficient level of predictability for more than 60% of the measurements was found. The log measurements in the partly frozen state are inconclusive because Edyn data fluctuate in the presence of both liquid and frozen water. For the completely frozen logs, a correction is introduced as a precaution that avoids an overestimation of Edyn in the unfrozen state.

Prediction of basic timber properties like moisture content and density is an important factor for quality control in timber industry. This paper deals with the detection of moisture content and density of spruce (Picea abies). It describes the calibration and validation of the newly developed microwave prototype on the basis of 480 measurements for moisture contents between 8 and 19% and densities between 340 and 600 kg m -3 . The calibration and first validation set lead to R 2 §92% in both cases. The prediction for a second and third validation decreases as especially the range of moisture content for these pieces was limited. Compared to other moisture and density measurement systems, the prototype showed good performance. With this technology it is possible to detect moisture and density of a piece of timber contact free and non-destructive with high prediction accuracy for both parameters in one pass.