Abstract: The invention relates to a method for measuring a relative velocity between an object surface (O) and a sensor (1) having at least one light-sensitive element (2) according to the spatial frequency filtering method, wherein the light-sensitive element (2) is read out at time intervals, and wherein the spatial frequency filter is designed as at least one masking grating having a variable grating constant. The method according to the invention is characterized in that the relative velocity is firstly measured with a first grating constant k1 having a large period length and/or over a short observation time period t1 (rough measurement) and then the measurement of the relative velocity is repeated for an exact determination using a second grating constant k2 having a small period length and/or over a long observation time period t2 (fine measurement). The invention further relates to a sensor for velocity measurement.

Abstract: The invention relates to a device and a method for determining the vertical spacing of objects while carrying out positioning tasks with a vertical travel portion.

Abstract: A method for measuring a velocity of an object surface relative to a sensor having a plurality of light-sensitive elements arranged spaced apart from one another. Each light-sensitive element produces an element signal indicative of detected brightness. The method includes receiving element signals at intervals of time, producing a frequency signal according to a spatial frequency filter method, producing a correlation signal according to an image processing method, and monitoring the produced frequency signal regarding at least one of a frequency value and at least one quality feature of the frequency signal. The method also includes selecting a produced signal for determining the velocity of the object surface relative to the sensor, and selecting the correlation signal in the event that at least one of the frequency signal lies below a threshold frequency value and the frequency signal fails to achieve a threshold quality feature value.

Abstract: A monitoring device and method for monitoring machine movements, moving parts of machines, gates, doors and the like, includes controller means with at least a first receiver for wirelessly receiving monitoring signals and a first transmitter for wirelessly transmitting activation signals, and includes monitoring means with at least a second receiver for receiving the activation signals, a second transmitter for transmitting monitoring signals, and at least one monitoring sensor for monitoring an unwired signal path. In one embodiment, the monitoring sensor is an optical safety shut-off bar that monitors the transmission of transmission signals via the unwired signal path.