Accurate indoor visible light positioning method using four LEDs and a smartphone camera

Indoor visible light location using a smartphone camera as a receiver has recently acquired popularity due to its advantages, particularly its high accuracy of localization when compared to other techniques. Even if it has been the object of several works, research on this topic is still going on, in order to meet the requirements of indoor positioning mobile applications. In this research, we propose a complete accurate positioning method based on a camera model and a minimization algorithm that uses four Light emitting diode (LEDs) to estimate the smartphone’s arbitrary position. The critical process of identifying the pictures of the LEDs in the image plane is also addressed. The proposed method has the advantage of achieving high positioning accuracy even when the smartphone is tilted, without the need of an additional sensor. Various experiments were carried out to evaluate the performance of the proposed method in various positions of the smartphone. The results reveal that even when the smartphone is tilted, this method achieves an excellent positioning mean accuracy, which is better than 2 cm.