|Stereomicroscopy for 3D
The stereomicroscopy means that the stereoscopy is incorporated in the optical microscopic technique to provide a three-dimensional view of the surgical field. Recently, the high-resolution three-dimensional stereoscopic images are reproduced in such a way that it allows a direct watching of microscopic imaging. Because of the perception of depth, the 3D stereoscopic imaging has various applications.
The industry has been trying to create a 3D display for more than 10 years by using a wide range of pure optical schemes. Glasses and helmets, microlens screens, and a parallax barrier, did not satisfy customers and had insignificant commercial success. There are a number of reasons for this: poor quality of 3D images, physiological and psychological problems including the "fatigue" effect, high price of the end unit, and dramatic changes needed for adoption to entertainment, and monitor manufacturing industries. Recently, there has been significant development in the field of stereoscopic imaging devices because of technology improvements, and all the research on stereoscopic devices has focused on the new 3D display technology. Hence, there is a need to develop an image acquisition, recording, and playback device and search for a stable display method in the operating microscope field.
The earlier studies show that in medical education, the depth perception can be enhanced by displaying stereoscopic video content to medical students on personal stereoscopic displays. Although multimedia teaching cannot replace hands-on experience or direct contact with patients, in many cases physical presence in a theatre is no longer necessary to understand the idea of surgical concepts that are designed to remove pathology and preserve intact structures plus restore function. From these earlier results it can be concluded that a stereoscopic image displayed in high resolution on one large screen could facilitate orientation for the junior surgeon so that the right surgical plane is found and maintained while image resolution is still comparable to the original optical image. The study on a laparoscopic model shows that stereoscopy made no difference to the operation time of an experienced surgeon, although it facilitated orientation and reduced operation time for inexperienced surgeons compared to monoscopic vision. Although the system can require all viewers to wear polarized filter glasses, the stereoscopic viewing impression is robust against position changes and the number of viewers.
Stereoscopy devices have been used in the operation theatre before, either as a standalone solution or in combination with three-dimensional volume rendering from computer-assisted surgery. However, these devices have rarely served as the main source of visual information for the surgeon, as their resolution is limited. In modern techniques, stereoscopic video in high-definition resolution has been used to replace the direct microscopic view to perform surgical applications.
There are three steps involved in introducing 3 D in microscopy and they are:
b) Stereoimage processing
c) Stereorecording and display
The stereo microscope uses two separate optical paths with two objectives and two eyepieces to provide slightly different viewing angles to the left and right eyes. In this way it produces a 3D visualization of the sample being examined. There are two major types of magnification systems in the stereo microscopes. One is the Geenough type, which is fixed magnification in which primary magnification is achieved by a paired set of objective lenses with a set degree of magnification. The other is a center mounted object (CMO) type that has zooming or pan pancreatic magnification, which are capable of a continuously variable degree of magnification across a set range. In order to acquire the stereoscopic image we have to use the CMO type, which is easy to attach to the CCD camera or order device. Fig 2.2 shows a schematic diagram of the stereoscopic image acquisition system using the CMO type of the stereo microscope. By adding the beam splitters in the two optical paths of the stereo microscope we can acquire stereoscopic video images through the CCD cameras and the eyepieces are always the same. The system is a manufactured basic structure of the parallel stereo camera, which is two small HD CCD heads attached on a special camera base device.