A light-conductive board and a rear light module using the light-conductive board is disclosed. The locating assembly includes a body. Accuracy and reliability is achievable by calculating three kinds of reliability based on the distribution of the image characteristic quantities and then judging whether additional learning is necessary, or selecting and adjusting image characteristic quantities and estimation engine based on the reliability. In addition, optical alignment structure is simple with increased freedom in arranging elements, and the number of parts required is sharply reduced. The compensation module is operable to compensate the electrical isolation between the first and second signals and the outbound wireless signal.