Signage display device provided in interactive swimming pool

Claim 16. The method of claim 15, wherein the detecting of a user based on intensities of the extracted first and second RGB reflective lights comprises:

• determining, when an intensity of at least one of the extracted first and second reflective lights is above a first threshold and below a second threshold, that the user is located in a sensing area of the first and second sensors, and comparing intensities of the extracted first and second reflective lights to determine a first swimming pool area where the user is located;
• and
• determining, when an intensity of at least one of the extracted first and second reflective lights is above the second threshold, that there are a plurality of users in the sensing area of the first and second sensors, and calculating a user density of a swimming pool area formed above a signage display module disposed between the first and second sensors.