Minimally invasive surgery, developed during the last 15 years becomes a major field of surgical intervention. In comparison with the traditional open surgery, this minimally invasive procedure has much less adverse effects on the patient. Patients benefit from little damage around the focus of surgery. Video-guided remote surgery provides this minimally invasive treatment. In video-guided surgery, an imaging device, as such as a laparoscope, is inserted through an incision to visualize the surgical scene inside the patient’s body. Normally, the imaging device has a wide-angle lens to maximize the field of view and to minimize the incision/trauma. However, a significant geometric distortion is created in the image with the wide- angle lens. Furthermore, an ordinary imaging device does n...[ Read more ]

Minimally invasive surgery, developed during the last 15 years becomes a major field of surgical intervention. In comparison with the traditional open surgery, this minimally invasive procedure has much less adverse effects on the patient. Patients benefit from little damage around the focus of surgery. Video-guided remote surgery provides this minimally invasive treatment. In video-guided surgery, an imaging device, as such as a laparoscope, is inserted through an incision to visualize the surgical scene inside the patient’s body. Normally, the imaging device has a wide-angle lens to maximize the field of view and to minimize the incision/trauma. However, a significant geometric distortion is created in the image with the wide- angle lens. Furthermore, an ordinary imaging device does not provide accurate information on the lateral size and depth of the imaged object. These factors introduce the limitations of current video-guided surgical treatment.

In this work a miniaturized three-dimensional endoscopic imaging system is presented. The system consists of two imaging channels with 2 mm separation between their optical axes. One of the channels was used to obtain the image from the object of interest. The other channel was used to project a structured light and generate feature points on the imaged object for the measurement of surface profile. The structured light of dot matrix was generated with a collimated monochromatic light source and a holographic binary-phase grating. The imaging and projection channels were calibrated and the distortions of the two channels were corrected using a modified pinhole camera model. The surface profile was extracted using the triangulation between the projected feature points and the channels of the endoscope. The imaging system was evaluated in three-dimensional measurements of several typical objects. The experimental results show that spatial information of the objects with different shape and dimensions can be recovered with high accuracy. In vivo three-dimensional imaging at human skin and oral cavity were conducted. The results demonstrate the potential of the technology in clinical applications.