It is of great value to understand the variation of the light field as viewed from different directions in the sea. Satlantic Inc. developed a radiance camera (RadCam) for imaging the visible light field over an entire hemisphere with a high dynamic range. In the current project, I propose a quantitative estimation of the radiance distribution in the lab and in different sea water environments with this new camera. I will design and carry out a series of advanced calibration procedures for the camera system so that the grayscale camera images are accurately converted to radiance values. Then I will apply the same procedures to radiance measurements in the seas. A general picture of the underwater radiance distribution and its variation is expected after this study, which makes a principal contribution to the academic knowledge base. This project solves the critical calibration problems facing the partner and enables the partner to leverage the cutting-edge research to further their development.