High-Speed Image Capture Of Three-Dimensional Medicinal Ultrasound System And The Research On Its Synchronous Controlling Method

According to the requirement of three-dimensional ultrasound medicinal diagnosis system, the author took on the manufacture of the three-dimensional ultrasonic system for real time image capture and the preprocess of the images, etc. With the aids of DC30 video capture card and electromagnetic orientation system of Bird, the author accomplished the software design of a bulk capacity ultrasonic images and three-dimensional orientation collecting system and introduced a plantar switch as the start signal of collection. The author designed an electrocardiograph for picking up the cardiogram signal while capturing the ultrasonic images, then accomplished the auto-detection of R wave by means of dynamic threshold and multi-standard. The detected R wave can be used to select the same time and phase of the two-dimensional ultrasonic images of the heart for the later three-dimensional reconstruction. The captured ultrasonic images are stored into the high-speed disk in AVI file format. The author realized the successive or frame- by-frame playback and some editing functions such as zoom out, zoom in, copy, delete, of the ultrasonic images. Besides, the author achieved the transformation of file format form AVI to BMP, and this will do a great convenience to the later process of edge enhancement and edge outlining and provide the original data for three-dimensional surface reconstruction. Furthermore, the author analyzed the reason why timing interrupt based on software can not meet the demands of real timer capturing and controlling system under the conditions of the multi-tasking operating system and illustrated the principles of kernel management and the hardware interruptions disposing mechanism in Windows 98 and described the method of acquiring real time clock interrupts, which is the key technology of real time controlling system design based on the hardware of PC and Windows 98. The author completed the design of the high precision real time clock in Ring0 layer by means of virtual device driver. In the design of the whole system software, the author used mixed programming method with VC++6.0 and inline assemble languages. This programming manner makes full use of the advancement of VC++ 6.0 and the lightweight of the assemble language and can greatly enhance the efficiency and the running rate of the program.