On Vision Navigation Technology For An Endoscope

The research on intelligent medical devices and medical robots is currently an important area. Among its applications is the minimal invasive surgery (MIS), which has improved levels of traditional diagnosis and treatments. More and more forbidden zones of surgery could be reached and many kinds of diseases could be cured effectively. Endoscopy, an important technology of MIS, mainly uses endoscope as a diagnosis device. While colonoscopic diagnosis has become an effective therapy to cure colon illness, there exist some problems as perforation. Therefore, it is worthwhile to do research on intelligent modification for endoscopes.This dissertation is mainly about the visual navigation technology of the endosope. The main contents of the dissertation are as follows:(1) The particularity and complexity of the endoscopy diagnosis is introduced. By references and interviews with doctors, the manipulation strategy of doctors is analyzed and main steps for vision navigation in endoscopy diagnosis are proposed. The real-time images are picked up by CCD camera and sent to a computer. By analyzing these images, the computer automatically controls the pose of the tip of endoscope or gives suggestions to the doctor who pushes the endoscope into the colon successfully and safely.(2) As a basis for detailed research on visual navigation, a series of techniques are investgated including endoscope images acquisition, pretreatment of endoscope images, feature extraction of image and so on. Several algorithms of these techniques are introduced as well.(3) Dark region analysis: The principle of endoscope navigation based on dark region is introduced firstly. Three algorithms of auto-thresholding are presented which are used to find the path in the colon. These three auto-thresholding algorithms, known as the method of simple thresholding, the auto-thresholding algorithm based on Ostu's method and the histogram segmentation algorithm based on wavelet, are used to extract the lumen from colon images. The comparison among three algorithms is carried out.(4) Contour analysis: At first, the limitation of dark region method is presented. According to the fact that there are many close muscle lines in colon surfaces, the method of contour analysis is introduced. Two algorithms, based on contour grouping and edge energe detecting respectively, are described to detecting path of the endoscope. The comparison between these algorithms is carried out.(5) Navigation strategy: The application of multi-sensor navigation is introduced...