A method for verification of a video signal employs measurements of luminosity of video display monitors. A current consumption of the video display monitors is measured at a sampling rate. The measured current display consumption is used as a measure of the total luminosity of the display screen at the time of measurement. A special software module within a digital recording unit is used to calculate an aggregate luminosity of every recorded video frame. A central verification system generates subtle yet measurable changes in illumination of the surveyed scenes. The central verification system detects and analyses the correlated changes in display monitor's current consumption to verify that the assigned monitor is actually displaying its assigned scene. The software module produces an event notification along with a timestamp of the event whenever the frame luminosity changes between adjacent frames.