A measuring device is used to increase a contrast of a plurality of measured values displayed in a spectrogram or spectral histogram and contains a data-acquisition unit, a computer unit and a statistic unit. The data-acquisition unit is embodied to detect a plurality of measured values to be displayed. The statistic unit is embodied to calculate a distribution which contains the frequency of occurrence for every level value of the measured values to be displayed. The computer unit is embodied to specify a dynamic range, over which the contrast extends. In this context, a specified proportion of the level values which image the noise are not used for the specification of the dynamic range.