A method and a projector for projecting an image pixel by pixel includes a control unit controlling a light diode device for emitting visible light, pixel by pixel, in accordance with the image to be projected and controlling an infrared diode device for emitting infrared radiation pixel by pixel based on the image to be projected and on a back radiation model, in such a way that a setpoint back radiation intensity measuring signal to be expected pixel by pixel for the actual back radiation intensity measuring signal has a predetermined value for predetermined pixels; and a radiation intensity detection device detecting pixel by pixel a back radiation intensity of reflected visible light and reflected infrared radiation and generating pixel by pixel an actual back radiation intensity measuring signal based on the detected back radiation intensities.