[Periodogram analysis for signal and noise evaluation in roentgen video signals]

Movements of the heart, the large vessels and the gastrointestinal tract can be evaluated for diagnostic purposes using fluoroscopic video systems. A new means of quantitatively evaluating the signal and noise components of the video signal is described. The signal and noise power components are determined from the periodogram after prior Fourier analysis. Variance is reduced by averaging and keeping the measuring conditions constant. For measurements of signal transfer properties, a radiological phantom capable of producing sinusoidal movements of the edge of the object was developed. An analysis of the performance of the theoretically derived evaluation parameters was carried out at a fluoroscopic unit under clinical conditions. Periodogram analysis makes possible objective image quality evaluation in clinical motion studies and in the technical quality assurance of fluoroscopic video systems. The use of a compact PC-based video measuring system renders application both practical and easy.