Abstract A method of restoring the color information in a black-and-white video camera is proposed in this paper. The method is demonstrated by an experiment. The experiment contains two steps. Firstly, an environmental coefficient matrix is calculated by taking pictures on a calibration plate. Then, a restored picture is estimated by Matlab. The experiments have been done in different settings and in another dual-mode camera. All restored pictures are compared with the original ones. The results indicate that this method has precision, repeatability and adaptability to environment. If the system can be put to practical use, it will give clues to the criminal investigation.