Lighting is the basic requirement of the conference room. The camera has an automatic color equalization circuit, which can provide true and natural colors. The light incident from the window (color temperature about 5800K) is higher than that of fluorescent lamp (3500K) or tricolor lamp (3200K). If there are two kinds of light sources (natural light source and artificial light source) indoors, video images of blue projection and red shadow area will be produced. On the other hand, the meeting time is random, and the illumination and color temperature of natural light sources are different in the morning and afternoon. Therefore, the meeting room should avoid using natural light sources and use artificial light sources, and all windows should be covered with dark curtains. When using artificial light sources, cold light sources, such as "tricolor lights" (R, G, B), should be selected to obtain the best effect. Avoid using thermal light sources, such as iodine tungsten lamp with high illumination. The illumination of the meeting room should be 500LUX for the camera area, such as the human face. In order to prevent the uneven light of the face (eyes, nose and full shadow), the tricolor lamp should be rotated to a suitable position, which was determined when the conference TV was installed. For monitors and projection TVs, the illumination around them should not be higher than 80LUX, but should be between 50 and 80 lux, otherwise the viewing effect will be affected. In order to ensure the readability of documents and charts, the illumination in the chart area of documents should be no more than 700LUX, and the chairman area should be controlled at about 800LUX.