The present invention relates to an apparatus for determining an intensity and/or a phase of intensity modulation of an intensity-modulated electromagnetic radiation signal, having a detector and imaging optics for imaging an intensity-modulated radiation signal onto the detector. In comparison with this, the present invention addresses the problem of providing an apparatus for reducing scattered light influences on an intensity and/or phase determination of the intensity modulation of an intensity-modulated electromagnetic radiation signal. In order to solve this problem, the invention proposes configuring the apparatus of the type mentioned at the outset in such a manner that said apparatus has at least one scattered light reference pixel, which is arranged outside an imaging section of the imaging optics and is set up in such a manner that said pixel records measured values for an intensity-modulated scattered light signal during operation, and a determination device which is set up in such a manner that said determination device processes measured values from at least one pixel in a pixel matrix of the detector inside the imaging section as a first data input and measured values from at least one scattered light reference pixel as a second data input during operation in such a manner that said determination device determines a corrected intensity of the intensity-modulated radiation signal and/or a corrected relative phase between the intensity modulation of the intensity-modulated radiation signal and a reference signal at least for the pixel inside the imaging section and provides said intensity and/or phase as a data output.