Biophoton emission is the ultraweak light emission originating from almost all of the living organisms in nature, regardless of various differences in biological hierarctry, in an effort to investigate the essential role in vivo and fundamental mechanisms of biophoton emission, we have developed a variety of methods and techniques to be used for noninvasive and nondestructive measurements and analyses of biophotonic information in terms of emission intensity, spectral distribution, spatial and temporal distributions, polarization and correlation. We describe, in this paper, the details on the techniques especially for ultra-sensitive measurement of spatio-temporal biophoton distribution, namely two-dimensional imaging, and several new findings on the living biophotonic systems.