Abstract: A method for real video time size selection for objects represented as video images which are to be filtered out so as to be classified as to their shape, including the steps of: recording the video image with a scanning recording beam; digitalizing the video image; providing at least one selected mask representing a selected object image shape; examining the digitalized image, pixel by pixel, with the selected mask while displacing the selected mask over the video image in synchronism with the recording beam; and, upon the occurrence of a given degree of coincidence between a selected section of the image and the selected mask, indicating detection of the object as such.

Abstract: A method for reducing the background count rate in radioactivity measurements with a coincidence-anticoincidence evaluation, in which pulses from a detector and pulses from a shield counter device are amplified and compared based on a time relationship, reduces the zero sample counter rate of the detector by supplying the amplified pulses to analog/digital converters which convert the pulses to digital values at a predetermined clock frequency. When a detection pulse is identified, digital values are transferred to a PC system. In the PC system the height, shape, or slope of the detector pulses is compared to the height, shape, or slope of any contemporaneous pulse from the shield counter device. Circuitry for performing the method is also disclosed.