- Research Article
- Open Access
High-Definition 3D Stereoscopic Microscope Display System for Biomedical Applications
© The Author(s). 2010
- Received: 1 August 2009
- Accepted: 3 December 2009
- Published: 19 January 2010
Biomedical research has been performed by using advanced information techniques, and micro-high-quality stereo images have been used by researchers and/or doctors for various aims in biomedical research and surgery. To visualize the stereo images, many related devices have been developed. However, the devices are difficult to learn for junior doctors and demanding to supervise for experienced surgeons. In this paper, we describe the development of a high-definition (HD) three-dimensional (3D) stereoscopic imaging display system for operating a microscope or experimenting on animals. The system consists of a stereoscopic camera part, image processing device for stereoscopic video recording, and stereoscopic display. In order to reduce eyestrain and viewer fatigue, we use a preexisting stereo microscope structure and polarized-light stereoscopic display method that does not reduce the quality of the stereo images. The developed system can overcome the discomfort of the eye piece and eyestrain caused by use over a long period of time.
- Stereo Microscope
- Stereoscopic Image
- Stereoscopic Display
- Stereoscopic Video
- Microscope Eyepiece
Humans receive a great deal of information through the five senses and receive about 70% by the visual sense. Video techniques based on the visual sense are extending to television broadcasting, machine, and image processing applications as well as to other applications. Video techniques have developed rapidly with the realization of HDTV broadcasting. Recently, we have tried to reproduce high-resolution three-dimensional stereoscopic images in a way that allows a direct watching of microscopic imaging. Because of the perception of depth, the 3D stereoscopic imaging has various applications [1–3].
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, which are all well known, 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, we saw a need to develop an image acquisition, recording, and playback device and search for a stable display method in the operating microscope field.
Two earlier studies [4–7] show that in medical education 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 we 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.
There have been few reports on the evaluation of stereoscopy in surgery. Von Pichler and coworkers noted in their study on a laparoscopic model 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 our study, stereoscopic video in high-definition resolution has been used to replace the direct microscopic view to perform surgical applications.
Our work focused on the development of a full HD stereoscopic imaging device with acquisition, display, recording, and playback technology for the operating microscope, experiments on animals, HD stereoscopic content development in biomedical applications, and so on.
The stereoscopic image acquisition device consists of a 3D camera using a stereo microscope with two small HD cameras. The recording system consists of a 3D Multiplexer/DeMultiplexer device for making one channel image from two channels images of the left and right channel, and vice versa . Last, the assessment of a wide number of display types has led to the choice of well-matched conventional television displays with images separated by polarized light filters for our medical applications. The goal of our approach is to develop a system which allows a full HD stereoscopic imaging system for the surgeon or for experiments on animals through stereo microscope optics.
This paper is organized as follows. Section 2 illustrates our proposed full HD 3D stereoscopic microscope imaging system which can be applied to biomedical applications. Section 3 describes the evaluation results obtained from real animal surgeon test by using the developed system, and finally, the results of this paper are summarized and future research directions will be presented.
2.1. Overview of the HD Stereoscopic Microscope Imaging System
Many problems of using a microscope relate to the fact that the surgeon's eyes must remain fixed on the microscope eyepieces. In this case, eye flicker affects eye fatigue very much. If an observer's eyes flicker, it is difficult to focus on the object. It also cannot be observed by the other surgeons at once. In the case of a 2D image display using a microscope, a wrong diagnosis or mistake in a surgical operation can occur because of the lack of depth information and difference between the 2D image and the human visual system. Using an SD (640 480 pixel) quality image can be difficult to precisely recognize.
2.2. Stereoscopic Image Acquisition of the Stereo Microscope
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 [11–13].
where is the focal distance of the cameras, and s is the distance between the left camera and the right camera. Like the simple equation (1), it is easy to calculate the depth or distance.
2.3. Stereoscopic Display System
Stereoscopic display methods.
Character (advantage or disadvantage)
Binocular stereoscopic (use of special glasses)
Simple but cannot display full color
Some time change from left to right image (unstable)
Bulkier than many alternatives, but does not reduce the information content of the picture
Uncomfortable for the special glasses
Do not use special glasses, but low or reduced resolution display, limited viewing angle or position, and difficult of the embodiment
2.4. Stereoscopic Image Processing Device for Recording and Playback
2.5. System Development
In this section, we describe the system development of the HD stereoscopic display system of the stereo microscope. The system consists of a stereo microscope (Olympus SZX model), 3D Mux/DeMux, and stereoscopic monitor. The stereoscopic image can be acquired by each of the two Full HD CCD camera ports of the Olympus SZX stereo microscope.
The 3D Mux/DeMux device plays an important role in the image recording and playback with a recording device like a tape recorder or semiconductor memory. The 3D Multiplexer input receives from the synchronized HD component signals of two HD CCD cameras. A full HD1080i analog image converts to a digital image through the ADC7403 (Analog Device Company), which can control the video mode or clock speed by I2C. The function of Multiplexing/De Multiplexing is realized by the process of the writing and reading in the frame buffer about the input image.
Specifications of the full HD microscope stereoscopic image display system.
Image acquisition part
ICONIX / HD-HR1
1/3 inch 3CCD Prism
1080i /50,60 Hz
Stereo microscope Ziess/Nikon/Olympus, and so forth
3D Image Display Part
3D Display Method
2Channel Analog or Digital Video
3D Image Recording Part
Spatial Compression/Frame Seq.
2Ch HD Video 1080i/60 Hz
1Ch HD Video 1080i/60 Hz
3D De Multiplexer
HD Multiplexed Video Signal
2Ch HD Video Signal
In general microscope magnification environment, it is difficult to display marks of sutures (11/0) appeared after surgical operations through SD images more clearly, but these marks can be confirmed in full HD vivid images. Since full HD video standards are established for highest resolution, we make design to full HD microscope stereoscopic display system which consists of the microscope stereoscopic image acquisition, recording/playback device, and stereoscopic display monitor. And also, the embodiment system proposed in this paper has been evaluated as the best device in the field of stereoscopic display system.
The evaluation results of the proposed system compared with existing optical microscope system.
Optical microscope system
Proposed HD video system
Accuracy (For image resolution or quality)
Very good (directly watching object through the eyepieces, just depend on optics)
Good (full HD image quality, depend on imaging system)
Eyestrain (Fatigue for work)
Much of eye fatigue (The more long time operate, the more raise eyestrain)
Little fatigue (have fatigue for watching display device)
Not good; just single or double working (Difficult to receive to assistance to help)
Good; working together several persons (Easy to receive to assistance to help)
- Discomfort for the single working
- Just need to time for adaption
-Useful at simple working
-Useful at many applications
Impossible (Cannot reuse information because the system is the device directly watching a scene)
Good (It is very useful because our system includes 3D Video record/playback device)
System configuration settings
Easy (Difficult to analysis or evaluate for work because depth information can't be recorded/playbacked)
Difficult (Difficult to configure, but because of including the 3D Video record/playback device that is very useful)
In the case of an optical microscope system, image quality is very good, but it is limited at the actions because of the fixed eyepieces, which is a major cause of eyestrain and a serious problem of the optical microscope system. Our proposed system on the other hand needs time to adapt for the display system but more effort can improve accuracy.
According to the evaluation test, an ideal microscope display system will have to improve or develop like as follows:
(i)microscope image acquisition device—wider of field of view (FOV), color quality like human vision, and low-impact illumination by changing of environment around;
(ii)stereoscopic video recording/playback device—minimum changing of resolution or image quality when 3D multiplexing or demultiplexing;
(iii)stereoscopic display device—problem of the display monitor size and wearing the special glasses.
The long hours of intensive work looking through an operating microscope have always been accepted as the price paid for working in this surgical subspecialty. Looking through microscope eyepieces, while performing a complex microsurgical reconstruction for hours sitting or standing relatively motionless often in uncomfortable positions, is not uncommon. It is not unreasonable to see how years of performing surgery under these strenuous physically demanding conditions could lead microsurgeons to prematurely retire from active practice, and in doing so, deprive the field of what could be their most fruitful years. The use of video technology in many surgical specialties is now considered routine. As an alternative to the operating microscope, advances in video technology can now permit the surgeon to view a microsurgical field on a video monitor in three dimensions without the necessity of physically looking through the microscope eyepieces. The conventional microscope magnifies the operative field and brings it mechanically and stereoscopically into the surgeon's view.
In conclusion, in the present study, we evaluated the use of the full HD stereoscopic display system of a stereo microscope and found that this technique provides several advantages over conventional microworking techniques. However, our evaluation of the technology showed less than optimal loss of illumination, inadequate par focal capability, and loss of depth and width. This study's preliminary data has guided the refinement of the stereoscopic display system for the stereo microscope.
Development of a full HD 3D stereoscopic microscope display system capable of providing a clear and accurate sense of depth perception has been a critical requirement in the rapidly evolving field of minimally invasive surgery and inspection. Our stereoscopic display system for the stereo microscope will be ready for widespread implementation and will positively affect the way microscopes work. The employment of surgical microscopy in the field of surgery has significantly contributed not only to the advancement of surgical technique but also to the operative outcome as well.
This work was supported by the grant of the Korean Ministry of Education, Science and Technology (Regional Core Research Program/Chungbuk BIT Research-Oriented University Consortium).
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