Abstract: The invention relates to a method and device for determining the perfusion of blood in a body member. Furthermore, the invention relates to a computer program for determining the perfusion of blood in a body member. To provide a technique to ensure that the actual patient perfusion condition does correlate with the calculated perfusion index value over a broad variety of patient conditions, a new method of determining the perfusion of blood in a body member is suggested, the method comprising the steps of: producing electrical measuring signals from a non-invasive photometric measuring process, normalizing the electrical measuring signals and determining a perfusion index from the normalized signals, using an energy value of at least one signal pulse.

Abstract: A method of determining the concentration of a component from the intensity of electromagnetic waves with at least two selected wavelengths which are reflected by human tissue or transmitted through human tissue comprises the step of converting first intensities of the received electromagnetic waves into at least one first and one second electric signal. Following this, a continuous first temporal average value of the first signal and a continuous second temporal average value of the second signal are formed. A first alternating component is continuously determined from said first signal and said first average value, whereas a second alternating component is continuously determined from said second signal and said second average value. Subsequently, a continuous ratio is determined from said first and second signals as well as from said first and second continuous temporal average values, with the exception of regions lying close to the zero passages of the alternating components.

Abstract: A method is proposed for determining the perfusion by evaluation of the light emitted by at least one light source and influenced by the arterial blood, by use of optical measuring means which measure the intensity variation as a consequence of the variation in arterial blood volume. According to this method, the perfusion is either displayed as variation in thickness from the sum of the parallel tissue enlargements d or as normalized volume. The perfusion is derived by one or more measurements of light intensity. According to the invention, for the first time a method for determining perfusion as a quantitative value is provided.

Abstract: A welder utilizes a focussed electron beam which is deflected along the processing path required to weld two pieces together and is also oscillated about the processing path in accordance with a modulation curve. The modulation curve is approximated by a sequence of points. The coordinates of the points in a predetermined coordinate system are read out sequentially from a digital storage and converted to analog signals. The analog signals are subjected to low pass filtering and then applied to the deflection system for the electron beam. The cut-off frequency of the low pass filter is a predetermined multiple of the readout frequency of the digital data. When the velocity of the beam along the modulation curve changes, the cut-off frequency and the readout frequency are adjusted simultaneously. Additionally, the position of the focus and/or the intensity of the electron beam can be varied as the beam traces out the modulation curve.