Kozyrev, unfortunately, depended on human devices which have the limitations of our own human system. We can't take simple photos of our dreams dreamt every night during all our lives and that is so from the beginning of human history. We would be unreasonable denying the objectivity of our dream experience just because it's subjective for human devices provided by science!!!!!

So, the only thing they can do in this sense is detecting some light, colors, brain activity, measure waves indicating some parts of the brain are working, ordering the desktop at night when the body sleeps....