A connecting device is designed releasably to connect a control section of an endoscope and a catheter control portion in a manner such that a channel opening portion in the control section of the endoscope and the catheter control portion are located close to each other. The plurality of heating element plates are each independently controllable with respect to energization. An edge of an object is extracted in the acquired image data using a preset edge threshold, and the object is recognized based on the extracted edge. Related methods, devices, and structures are also discussed.