Method for controlling imaging device, and imaging device

A system comprising:

• an imaging device that has at least a first mode to perform imaging in a first imaging wavelength band and a second mode to perform imaging in a second imaging wavelength band different from the first imaging wavelength band, and that allows switching of an operation mode from the first mode to the second mode or from the second mode to the first mode;
• and
• a controller that controls the imaging device, wherein the controller
• causes the imaging device to perform imaging in either of the first mode and the second mode,
• determines, with a predetermined frequency or in response to a predetermined trigger, whether to maintain a current operation mode or switch the current operation mode on the basis of first image information in the first imaging wavelength band and second image information in the second imaging wavelength band, and
• in accordance with a result of the determination, selectively maintains the current operation mode or switches the current operation mode.