Stereoscopic imaging platform with target locking automatic focusing mode

A method for imaging a target site with a stereoscopic imaging platform having a stereoscopic camera and a controller with a processor and tangible, non-transitory memory on which instructions are recorded, the method comprising:

• recording a left image and a right image of the target site, via the stereoscopic camera, to generate at least one stereoscopic image of the target site, the stereoscopic camera being movable relative to the target site;
• incorporating a lens assembly in the stereoscopic camera, the lens assembly having at least one lens and defining a working distance, the lens assembly having at least one focus motor adapted to move the at least one lens to selectively vary the working distance;
• connecting a robotic arm to the stereoscopic camera, the robotic arm being adapted to selectively move the stereoscopic camera relative to the target site;
• executing a target locking mode for maintaining a focus of the at least one stereoscopic image, execution of the target locking mode including:
• determining if the robotic arm is moving, via the controller, and restricting motion of the stereoscopic camera based on a current position of the at least one focus motor when movement of the robotic arm is detected;
• tracking a plurality of sharpness parameters when movement of the robotic arm is no longer detected, including a sharpness signal, a maximum sharpness signal and a derivative of maximum sharpness, wherein the sharpness signal is defined as a contrast between respective edges of an object in the at least one stereoscopic image, and the maximum sharpness signal is defined as a largest sharpness value observed during a scan period, the maximum sharpness signal being continually updated;
• and
• transmitting motor commands corresponding to at least one of the plurality of sharpness parameters when movement of the robotic arm is no longer detected.