Schematic illustration of experimental setup that found the human body, especially the face, emits visible light in small quantities that vary during the day. B is one fo the test subjects. The other images show the weak emissions of visible light during totally dark conditions. The chart corresponds to the images and shows how the emissions varied during the day. The last image (I) is an infrared image of the subject showing heat emissions. Credit: Kyoto University; Tohoku Institute of Technology; PLoS ONE
LiveScience cites some public release of the Kyoto University and Tohoku Inst. Technology but it sounds really strange. I don’t believe they do not say if the glass window was in-between – to assure that single photons are not just infrared light. It’s long known that CCD cameras are sensitive to the near infrared.