Cameras are often good but they aren’t perfect. Many of them are set to ignore small targets like pedestrians which makes bicycle detection difficult.
Induction coils work fairly well if you follow the positioning that Darth Lefty details. If I can see where the wires are (often covered during repaving), I have a nearly 100% rate of tripping the light. Often, even after repaving jobs, cracks develop over the wires and those can be a clue as to where to place your wheel.
It doesn’t matter much how sensitive the coil is but it does matter where my wheels are. I roll the entire length of the wire line in the pavement. If I just cross the line, there isn’t enough disturbance in the induction loop to change the current in the loop. Rolling along the wire is enough to trip the system.