Imaging system, processing device and illumination control method

A processing device configured to be connected to an endoscope including an imager configured to read out an electric charge stored in a pixel by using a rolling shutter method, the processing device comprising:

• a frequency detector configured to detect a frequency of a predetermined site of a subject;
• and
• an illumination controller configured to control emission of the illumination light during a readout period of the signal value, wherein
• the illumination controller is configured to
• set a phrase for an emission timing of the illumination light in an exposure period during which the imager stores the electric charge to be an identical phase at the frequency in each exposure period, and
• refer to respective phases set in exposure periods of chronologically adjacent frames to set an emission timing of the illumination light in the readout period.

An illumination control method implemented by an imaging system including:

• a light source configured to emit illumination light;
• and an imager configured to store an electric charge corresponding to an amount of received light and read out the stored electric charge as a signal value by using a rolling shutter method, the illumination control method comprising:
• detecting a vibrational frequency of a predetermined site of a subject;
• setting a phrase for an emission timing of the illumination light in an exposure period during which the imager stores the electric charge to be an identical phase at the frequency in each frame;
• and
• referring to respective phases set in exposure periods of chronologically adjacent frames to set an emission timing of the illumination light in a readout period of the signal value.