This paper presents an efficient approach for a vision based localization of multiple mobile robots in an indoor environment by using a low cost vision sensor. The proposed vision sensor system that uses a single camera mounted over the mobile robots field takes advantages of small size, low energy consumption, and high flexibility to play an important role in the field of robotics. The nRF24L01 RF transceiver is connected to the vision system to enable wireless communication with multiple devices through 6 different data pipes. The downward-facing camera provides excellent performance that has the ability to identify a number of objects based on color codes, which form colored landmarks that provide mobile robots with useful image information for localization in the image view, which is then transformed to real world coordinates. Experimental results are given to show that the proposed method can obtain good localization performance in multi-mobile robots setting.